ECOLOGY - MS. MCCRINDLE
Grade 10 PB Science
Unit 3 - Ecology
Favourite Organism Activity What is your favourite organism?
|Provide a complete scientific classification for your organism: |Where is your organism native to? (i.e. where does it live naturally?) |
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|Kingdom: | |
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|Phylum: | |
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|Order: | |
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|Family: | |
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|Genus & species: | |
| |In what type of ecosystem(s) does you organism live? |
|List two physical and two behavioural adaptations your organism has to help it |What organism(s) prey on your organism? |
|survive in its environment | |
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|What is your organism’s primary source of nutrients? (i.e. what does it eat?) |Choose one physical adaptation and describe how it helps your organism survive |
|What is your organism’s role in the ecosystem in which it lives? |What would happen if your organism was removed from the ecosystem (be specific). |
Ecosystem People Search
Directions: Find someone who can give you an answer for each of the items below. A classmate may only sign for one item, so you will need 18 different signatures. Sign only if you know the answer!
My signature means that I….
1. ____JAKOB___________________________ can name a scavenger.
2. ____ANHELINA___________________________ can define biodiversity.
3. ____JACK___________________________ have heard the call of a loon in the wild.
4. ____DAWSON___________________________ can identify an omnivore.
5. ____HANNAH___________________________ went canoeing last summer.
6. ____LINDSAY___________________________ can name an endangered species.
7. ____JILL___________________________ have dip-netted for pond organisms.
8. ____BENECIA___________________________ bring my lunch to school in a reusable lunch bag.
9. ____EMILY___________________________ have a bird feeder in my backyard.
10. ____FEBEN___________________________ have been to Oak Hammock Marsh or Fort Whyte Alive.
11. ____ANHELINA___________________________ can describe a forest food chain.
12. ____BRANDON___________________________ can name the gas that plants give off during respiration.
13. ____JAKOB___________________________ can identify the source of energy for ecosystems.
14. ____MS MCCRINDLE___________________________ can explain what a niche is.
15. ____BENECIA___________________________ compost organic waste materials in my home.
16. ____CARLOS___________________________ have picked up litter in my community.
17. ____ANDREA___________________________ have planted a tree.
18. _______________________________ can explain photosynthesis.
After the class discussion, write down two new things that you learned by doing the people search.
a. _________________________________________________________________________________________________
b. _________________________________________________________________________________________________
INTRODUCTION TO ECOLOGY
Hierarchy in Biology
Scientists have observed that living things have their place in a distinct hierarchy. This hierarchy starts with the simplest living things, cells. It goes up to the most complicated systems of organisms, which interact with and within their environment.
Examples:
Biosphere: Earth and the atmosphere
Biome: Boreal forest
Ecosystem: Forest
Community: Inhabitants of soil/grass where geese live
Population: Flock of geese
Organism: Goose
Organ system: Circulatory system
Organ: Heart
Tissue: Muscle tissue
Cell: Muscle cell
Your example: (it may be easier to start at the bottom)
|Biosphere | |
|Biome | |
|Ecosystem | |
|Community | |
|Population | |
|Organism | |
|Organ system | |
|Organ | |
|Tissue | |
|Cell | |
What is Ecology?
• The study of the __________________________________________________________
Ecology-related terms:
Biology - ___________________________________________________
Ecosystem - all the parts that make up a ___________________ and its ________________
• All living things require some form of energy to survive
o Life forms use energy to create the materials (______________________) and food that they need
o If the energy source runs out ( can’t make/get the food it needs ( _____________________________
• Virtually all life on Earth gets its energy from the _________________________
o The sun burns Hydrogen in a process called __________________
o Some life forms on Earth can use this energy directly to make food (ie. Plants)
o Some life forms on Earth can use this energy indirectly by eating other organisms (ie. Animals)
• The relationships between the organisms that harness the suns energy is analyzed when studying trophic levels
TROPHIC LEVELS
• A trophic level represents a specific level of a _______________________
o a series of organisms that show predator – prey relationships
• We will look at 4 distinct levels
__________ ______/ (1st level)
• ‘bottom’ of the food chain
• Most can use energy from the sun directly
• they can make the food they need
________________ (Levels 2-4):
• get energy from what it eats
• Fall into 1 of 3 levels:
|__________________ consumers - eat plants |__________________ consumers - eat small |__________________ consumers - eat larger |
|Ex. Herbivores |animals |animals, ‘top’ of the food chain |
| |Ex. Small carnivores |Ex. Large carnivores |
‘Kinds’ Of Consumers/Heterotrophs:
|Herbivore: |Carnivore: |
|an organism that eats only plants |an organism that eats only animals |
|Ex. _______________________ |Ex. _______________________ |
|Omnivore: |Detritivore/Saprotroph: |
|an organism that eats both plants and animals |an organism that eats the bodies of smaller dead animals, dead plant matter and |
| |animal dung |
|Ex. _______________________ |Ex. _______________________ |
|Decomposer: |[pic] |
|an organism that consumes any remaining dead plant and animal matter | |
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|Ex. _______________________ | |
Trophic cascades occur when predators in a food web suppress the abundance or alter the behavior of their prey, thereby releasing the next lower trophic level from predation (or herbivory if the intermediate trophic level is a herbivore).
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Ecological Pyramids
Pyramid of ________________
• A simple idea that describes why some organisms are rare while others are very common
• Can be explained looking at trophic levels:
o Big animals eat small animals
o ____________________________________________________________________________________________________________________________________________________________
o Small animals eat herbivores
o ____________________________________________________________________________________________________________________________________________________________
There are (usually) more organisms at lower levels of the food chain than the higher up.
*Question: Can you think of an example when this isn’t the case? How could this be?
Pyramid of ________________
• Refers to how much (mass) of a particular species or trophic level is present in an area
• In a defined area the biomass of producers is (usually) ___________________ than the biomass of primary consumers
• The biomass of primary consumers is (usually) __________________ than the biomass of the secondary consumers
o This trend continues as you move up the food chain
Pyramid of _____________________
• Energy can be stored in an organism
Ex. ___________________________________________
• Most of the energy that is stored in an organism is located in _______________________
• When an organism (higher on the food chain) eats another organism (lower on the food chain) the amount of energy transferred to the next trophic level is between ______________%
o This means that _______________% of the stored energy is lost
o Most is lost as ______________
o Some is lost as ______________
• When you eat something, only around _______________% of the energy available is used by your body
• This fact reveals the pyramid of energy flow
o The chemical energy available _______________ as the trophic level increases
o Explains why most food chains have only 4 links
Summary and Review
Please re-read the pages we just covered (4 – 8) and summarize the main idea(s) in a few sentences.
Use the space below to create questions that address the main ideas presented in these pages. You should answer these questions for homework tonight.
E.g. What is a trophic level? What are the names for specific trophic levels?
Favourite Organism Activity – Part 2 What was your favourite organism?_____________
|Referring to your favourite organism from the beginning of the unit, what are some things that might limit how many individuals of that organism can live in one |
|location? |
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|______________________________________________________________________ |
| Look at your responses to the previous question. Try to come up with a method to categorize your responses (sort them into categories). Describe your categories|
|below and indicate which of your factors from question 1 fall under each category. |
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|Category 1 __________________________ |Category 2 __________________________ |
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Populations
1. Definition = the _________________ of individuals of a species that live in a defined area
2. In nature, the population of any species reaches a maximum
3. The maximum population that can be supported by an environment is called the ______________________________
4 factors that determine carrying capacity
| Materials and Energy |Food Chains | Competition for Food: |
| | |Intraspecific |
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| | |Interspecific |
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| Population Density |
|Different organisms require different amounts of space |
|( __________________________________________________________________________________ |
|___________________________________________________________________________________) |
|The number of individuals of a species that live in an area at any one time is called population density |
|If the population density of a region gets too high overcrowding occurs. This leads to stresses that limit further growth. |
|Ex. ____________________________________ |
|Maximum Population Density: |
|Density-dependent factors: |
|Will increase or decrease the carrying capacity based on the SIZE of a population |
|Ex. ____________________________________ |
|Come up with 3 other density-dependent factors: |
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|Density-independent factors: |
|Will increase or decrease the carrying capacity _______________________________________ |
|_____________________________________________________________________________ |
|Ex. A forest fire |
|Come up with 3 other density-dependent factors: |
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Group Activity: Limiting Factors
Your group will choose one ecosystem and one organism that inhabits that ecosystem. Each group member will choose one of the four factors that determine carrying capacity and research how that factor affects your organism in your environment. You will then summarize and share your information with the rest of your group.
Ecosystem:
Organism:
|The factor you researched: | |
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Population Growth Curves
• A population growth curve displays the growth of a population over time.
• Most populations exhibit a sigmoidal (S-shaped) growth curve.
• This kind of curve has 3 distinct regions; A, B, and C
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Region A
• ______________________________________________
• Only a small number of organisms are sexually mature and able to reproduce
• The organisms may be adjusting to a new environment.
Region B
• Many organisms have reached sexual maturity and are reproducing
• The organisms have adjusted to their environment
• ______________________________________________
Region C
• ______________________________________________
• Population growth becomes constant.
• The number of deaths equals the number of births
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Summary and Review
Please re-read the pages we just covered (8 – 23) and summarize the main idea(s) in a few sentences.
Use the space below to create questions that address the main ideas presented in these pages. You should answer these questions for homework tonight.
INTRODUCED SPECIES
Biological invasion:
• occurs when ________________________________________________________
Exotic species:
• an organism that has invaded an ecosystem in which _________________________
• throughout the course of history, human beings have introduced many species to new ecosystems
• in some regions a large number of the species present are not indigenous
Examples:
New Zealand: ____% of species have been introduced
Canada: ____% of species have been introduced
Hawaii: ____% of species have been introduced
• not all species that were introduced survived
• if 100 new species are placed in a new ecosystem:
____ will die off
____ will successfully colonize
____ will become pests
• species can be introduced:
1. Intentionally: _________________
_________________
_________________
_________________
2. Accidentally: _________________
_________________
_________________
• introduced species have a huge impact on the balance of an ecosystem
Ecological impacts:
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
Economic impacts:
Russian wheat aphid $____ million/year
Mediterranean fruit fly $____ million/year
Zebra mussel $____ billion/year
Boll weevil $____ billion (since 1890's)
• introduction of species to new environments can be prevented in a number of ways
1. Inspections at travel centres
2. Ballast regulations
3. Control of established exotics
shooting & trapping
mechanical removal (plants)
pesticides
biological control
ASSIGNMENT: INVADERS!
PART 1: Invasive species, why should you care?
According to scientists, invasive species are a big problem, something we should all be concerned about. You might be asking yourself, "Why haven't I felt any impact from these organisms? I don't think they've affected my life." Go to and read the five reasons why should you care?
In your assignment: in your own words, write a short paragraph explaining EACH of these reasons
PART 2: Invasive species, how do you measure up?
Find out how your actions in and around your own home can impact invasive species introduction. Go to , click on interactive house: invaders, read the instructions and play the game.
A. In your assignment: write down the correct choice for each of the 10 clues and explain why?
B. Write down your total score!
PART 3: Help stop the spread of Invasive Species in Canada.
Task: Create a poster, pamphlet, or video educating the public on one chosen invasive species in Canada.
What your project must include:
• Description of the non-native ecosystem in Canada where the species is thriving. You should include information about the climate, landform, soil, native flora and fauna.
• Description of HOW the species was introduced.
• An overview of the known impact the invader has had on the native ecosystem. (You should include the conditions that allow the invader to thrive – see appendix for examples)
• Steps to eliminate this species and allow the ecosystem to return to a native balance.
• Pictures or other visuals and attempted creativity!
A Works Cited page with all information sources used. (Please use APA referencing)
How Invaders Thrive[1]
Aliens that are successful invaders are species that have some advantage over native species. These advantages are often enhanced when aliens move into ecological niches and thrive because, outside their natural environments, they are not held back by natural predators, parasites, disease, or competition in the way that native species are. Here are some Canadian examples of how alien species affect the species around them:
Competition: In many cases, invasive aliens out-compete native species for space, water, food, and other essential resources. For example, non-native starlings eliminate native Canadian birds like bluebirds, Red-headed Woodpeckers, and Tree Swallows by taking over their nesting sites. In addition, often aliens reproduce more successfully than indigenous species, quickly outnumbering the natives.
Predation: Some invasive aliens cause native populations to decline by being aggressive herbivores or predators – defoliating or overgrazing native plants or preying on native animals. Introduced rats and raccoons eat the eggs and nestlings of Ancient Murrelets and other seabirds living on the coast of the Queen Charlotte Islands. By depleting this population, the aliens may also be affecting the vulnerable Peale’s Peregrine Falcon, for which Ancient Murrelets are a food source
Disease: Sometimes, invasive alien species are diseases. Chestnut blight, a fungal disease that came to North America on nursery stock from Asia around 1900, has devastated the population of American chestnut trees in eastern Canada and the United States.
Parasitism: At times, invasive alien species feed on, or parasitize, native species, severely weakening them but not necessarily killing them.
Hybridization: Sometimes invasive aliens weaken the gene pool of native species by interbreeding with them, a process called hybridization.
Habitat alteration: When they change the structure or composition of a habitat, invasive alien species make it unsuitable for other species. This process is called habitat alteration. Careful management of the introduced moose is required to prevent overgrazing of forests and wetlands on the island of Newfoundland. Foresters in areas that are overpopulated by moose find that the animals’ grazing harms the regrowth of forest trees. This may seriously reduce future timber crops as well as the breeding habitat of songbirds that nest in deciduous shrubs. Overgrazing can also expose low-nesting birds and leave them vulnerable to predation.
Alien species can also seriously affect the environmental processes that all species, including humans, depend on. For example, the alien aquatic plant Eurasian water milfoil forms dense mats along shorelines and in slow-moving rivers. These mats sometimes interfere with the local nutrient cycle. When they die and decay, large amounts of phosphorus are added to the water, making it too rich in nutrients.
Summary and Review
Please re-read the pages we just covered (24 – 28) and summarize the main idea(s) in a few sentences.
Use the space below to create questions that address the main ideas presented in these pages. You should answer these questions for homework tonight.
Biodiversity and Sustainability
Productivity
• Refers to the ______________________________________________________
Ex: Ever heard of a garden being “productive”?
• Affected by _______________________________________________________
Food and Population
• The type and amount of food available in any given area affects the population that can be supported by it.
• Grain feeds more people than meat. (__________________________________________________________________________)
Food and Competitors
• If there is an increase in the type of food eaten by a particular animal, that population will increase. This is very apparent when we look at monocultures.
• ________________________________________________________________________________________________________________________________________________
• ________________________________________________________________________________________________________________________________________________
• ________________________________________________________________________________________________________________________________________________
Ex. A potato field has an abundance of potato plants. Potato bugs now have lots of food to eat and reproduce. We now have a huge number of potato bugs eating the crop. The farmer then needs to spray the field to stop the bugs from eating up his entire crop.
• The natural trend is to have a _____________________________________
• Many different kinds of plants and animals in a given area.
Pesticides
• Used to ___________________________________________________________
• Accumulate in an ecosystem
o Especially in the higher levels of the food chain
• This is called __________________________
Ex. The pesticide, DDT is a good example of how biomagnification works. Animals that are lower of the food chain (primary consumers) have less DDT in them. As you get higher in the food chain (secondary and tertiary consumers) the DDT increases.
Human consumption
• Humans use and affect more than ______% of the earth’s productivity
• This has a dramatic affect on other species
o ___________________________________________________________
• Which has led to an alarming _____________________________ (this trend can’t continue much longer)
Photosynthesis
• Plants take the sun’s energy along with carbon dioxide (CO2) and water to make food (carbohydrates) and oxygen.
____________________________________ ___________________
• Photosynthesis takes place in chlorophyll, which is found in the cell’s chloroplasts.
Cellular respiration
• Organisms breakdown food (carbohydrates) with the help of oxygen to produce carbon dioxide, water and energy.
_____________________ ______________________________
• Cellular respiration takes place in the cell’s mitochondrion
• _________________________ is pleural
NOTE:
• Cellular respiration is simply _____________________________________
• Only ____________________ practice photosynthesis, but all organisms (including producers) carry out _____________________________.
Bioaccumulation Assignment
Bioaccumulation is a process resulting in the concentration of substances in living tissues. It can be a natural healthy process or a toxic one. The U.S. Environmental Protection Agency uses the term persistent, bioaccumulative and toxic pollutants (PBTs) to categorize substances that raise human health and environmental health concerns.
In this assignment you will choose a topic, read a database article and fill in the worksheet. You will learn how to evaluate a scientific claim made in the article based on the quality of the source and evidence provided to back up the argument.
Go to:
Select one of the following topics, read the article and complete the worksheet.
1. Why is it dangerous to eat oysters and other shellfish in some months? What is red tide?
2. Through mercury contamination, Inuit Communities are experiencing higher levels of health problems. Why and what have the effects been on the health of the Inuit?
3. “A new study shows the typical pregnant woman has dozens of potentially toxic …chemicals in her body -- including ingredients found in flame retardants and rocket fuel.” What are the implications of this?
4. According to this article, the government needs to do more to regulate a common chemical found in electronics and home furnishings that make it difficult for them to burn. Should we follow the lead of Sweden in banning the chemical?
5. High levels of toxins such as mercury and DDT are found in polar bears and other animals in the Arctic north, thousands of miles away from pollution sources. Find out how they got there according to the following article.
6. Birds in Alaska are also being affected by bioaccumulation. Find out what is happening to them as a result of PCB’s and other chemicals.
7. Why are some of our becoming fish sad – according to this article?
To log in to EBSCOHost:
User ID: mmc
Password: buckeyes
Answer the questions on the following page on looseleaf.
Bioaccumulation assignment: Evaluating a scientific claim based on supporting evidence
1. What is the title of your article? What are two questions you predict the article will answer?
2. Who is the author of your article and what are his/ her/ their qualifications? (This might be found at the end of the article) If it is not listed, why might this be a problem?
3. When was this article published? Is it a recent date? If not, would it affect the findings of the article?
4. What is the title of the publication from which the article comes? Do you think it is a reliable source? Why or why not? Explain your answer. You might have to do some research here.
5. Read the article and make brief notes. Include at least 6 facts or ideas in point form (no sentences).
6. Write a 2 or 3 sentence SUMMARY of the article in your own words. This is called a PARAPHRASE.
If you use any of the author's exact words, you must enclose them in quotation marks, and put her/his name in brackets.
Example:
Original - "And before contemplating actual attempts to clone humans, there are severe technical hurdles that must be overcome." - David Suzuki
Paraphrase including quote - Cloning is presently difficult because of "technical hurdles." (Suzuki)
7. Find another website or article that either supports or contradicts the claim of your article.
What is the title of the article or page of the website?
What is the name of the magazine, newspaper, or website?
When was it published? If not listed, what are the implications of this?
Who is the author? If not listed, what are the implications of this?
List three main ideas of this article.
8. Based on your articles, make a simple comic strip (6 panels minimum) that shows the effects of bioaccumulation.
NITROGEN CYCLE
HONC
The most common elements found in living things are H_____________, O_____________, N________________, and C_______________.
Nitrogen is a main component of ______________ and ___________.
Nitrogen (N) along with potassium (K) and phosphorus (P) are the main ingredients of ___________________________.
While fertilizer is good for a plant, too much can _____________ or __________________ the plant.
• Nitrogen (N) helps plants turn ______________
• Phosphorus (P) helps plants to ______________
• Potassium (K) is important for ___________________________
Too much nitrogen can “burn” or kill a crop as in the case when an animal ______________________________________________
*Organisms can’t absorb nitrogen gas (N2) directly*
1) Nitrogen atoms must first be pulled out of the air and “fixed” (bonded) to other elements to form new compounds (such as ammonia) with the help of ___________________________________________________. This process is called ___________________________________.
2) __________________________ convert this ammonia into ______________________. Nitrates can be then used by plants for a source of nitrogen. They can also do this from the ammonia from decomposing organisms.
3) ___________________________________ convert nitrates back into nitrogen gas by a process called ________________________________.
NOTE: Animals can only obtain nitrogen from eating other organisms!
DISTURBANCES AND SUCCESSION
• Definition: Succession: ____________________________________________________
________________________________________________________________________
PRIMARY SUCCESSION:
• involves the series of changes that begins with a ___________________________
ex) ______________________________
• ends with ecosystem reaching maximum productivity for the environmental conditions
o called a ____________________________
Example:
1. pioneer organisms such as lichens are carried to the area by wind or birds
________________________________________________________________________________________________________________________________________________
2. plants that can grow in very thin soil (mosses) join the lichens
___________________________________________________
3. this causes more rock to break down, more decay and therefore more soil
___________________________________________________
4. a climax community is created
SECONDARY SUCCESSION:
• occurs when an __________________________________________________________
ex) ______________________
• process does not have to start with bare rock
_________________________________________________________________
• the new climax community is ______________________________________________
IMPORTANT POINTS:
• succession can usually change disturbed ecosystems back into productive ones
o severe disturbances can produce irreversible changes
o this is especially true if soil or a species is poisoned over a large area
____________________________________________________________________________________________________________________________________
ex) _____________________________
ORGANIC FARMING
• organic farming involves using agricultural practices that are environmentally friendly
• source of nitrates is ____________ and ______________ with nitrogen-fixing bacteria within the roots
• crops grown are very diverse and mature at different times of the year
• this ensures that different nutrients are released from the different plants on a continual basis
o relies on ____________ to control pests and weeds
• crop diversity reduces the need for pesticides
• due to susceptibility of crops to pests, smaller yields are produced resulting in higher prices
o many ______________ benefits are realized
Ecological Footprints
• The environment of a city cannot support the population of humans that live there. One reason is that a city is a place where large quantities of resources are consumed but few resources are produced.
o Nearly all the food that the citizens need to survive must be transported to the city from somewhere else.
o __________________________________________________________________________________________________________________________________________________________________
o The geographic location of a city population is not the same as its ecological location (the places where the population obtains its needs).
o __________________________________________________________________________________________________________________________________________________________________
o We are able to use resources that originate far from where we live because we have technology.
o __________________________________________________________________________________________________________________________________________________________________
• Dr. William Rees and his students proposed that population size should be combined with resource consumption and waste production, then converted into equivalent units of productive land and water area. He used the metaphor of an ecological footprint to describe his idea. It is summarized in the following equation.
• This equation reminds us that we depend on land and water ecosystems for our survival.
• ____________________________________________________________________________________________________________________________________________________________________________
• The concept of the ecological footprint helps us to see the "big picture" — the relationships between people and resources.
• ______________________________________________________________________________________
• ______________________________________________________________________________________
Introduction to Evolution Date:
Remember that science is based on the idea that the ; that there are a series of rules or “laws” that determine how the universe works and that these laws can be understood. If you keep an open mind (like a good scientist) you will more often than not be surprised how much about our world you can understand and explain. Resorting to to explain how and why things work is not scientific
Few ideas in science have caused more controversy than the idea that all living things are related to one another – the idea of evolution. Many people “disagree” with the idea of evolution, but as we will see – it can be (and has been) observed many, many times. The current theory about how evolution works is called . This theory was first described by and ; soon after, in 1859, Darwin published in one of the most famous books ever written: On the Origin of Species by Means of Natural Selection (it is often called just or The Origin).
At the beginning of the year we discussed the meaning of the term “theory” in science. Remember that a scientific theory is very different from the regular use of the term “theory”. In science, a theory is “an established scientific model that and ”[2]. In other words, theories only come into existence when many, many facts have been gathered – a theory explains why those facts happen. Here are some commonly accepted scientific theories (which are all based on facts gathered by observation):
|Atomic theory |Theory of plate tectonics |Quantum mechanics |
|Cell theory |Big bang theory |Theory of special relativity (Einstein) |
|Germ theory of disease |Chaos theory |Theory of molecular bonds |
In our unit on evolution we will focus on three primary questions:
1. ?
2. ?
3. ?
Each of these questions will require some background information and it will take us more than a week to answer each of these questions. You should anticipate a quiz at the end of each of these mini-units.
What is Evolution and How Does it Work? Date:
A formal definition of evolution is surprisingly easy: “a change in the of a over multiple ”. This statement brings up several other questions:
– What does “genetic make-up” mean?
– What is a “population”?
– What is a “generation” and how many generations do we need?
What does “genetic make-up mean?”
All living things that we know about have in their cells. DNA is the . Inside every one of the trillions of cells in your body is the information needed to make an exact copy of you. All living things are made using a code stored in their DNA. Every tree, every bird, every bacteria uses DNA to store the information necessary to build them. stored in an organism’s DNA is called its genome. Most living things have genomes that are quite long – if the DNA from one of your cells was stretched out it would be about 2 metres long (about 6 feet) and that’s in everyone of your cells!
DNA recipes are written is a special language that has only four letters: (these letters stand for different nitrogen bases: adenine, thymine, guanine and cytosine). These letters store the information used to (which are the building blocks of all living tissue). from material called amino acids, of which only 20 different types are known. The of amino acids and the in which they are put together determines the type of protein that is made. For example, one protein may help build a red blood cell, one may build a tooth, one may cause your eyes to be blue and another may cause your skin to be dark. Each is called a gene. in an organism put together are called its genome.
Every individual organism (except twins and clones) has a unique genome. Your genome is different from my genome; each fly’s genome is different from every other fly’s, and so on. However each , called a species, has many genes in common, this is called that organism’s . For example, all humans have many genes that are the same – these together are called the human genome. The human genome is surprisingly short – only are needed to make a human.
DNA is an amazing substance, it is capable of making many copies of itself with very few mistakes, but every once in a while there is a – for example an A instead of a T or a G instead of a C. These changes are called mutations. Most of the time a mutation does not result in a change to the protein, sometimes the result is a new protein which may or may not be a good thing for the organism.
It is mutations in an organism’s genome that cause different individuals of a species to look different. Some human examples: , , , etc.
What is a population?
A population is a group of who live in the same . This definition brings up several new words that must be understood as well:
• : the ability for two organisms to mate and produce offspring.
• Species: a group of organisms that can and produce . Species are different from populations because species can have multiple populations. As long as members of the population could mate and produce viable offspring, they are .
For example, the tiger (Pantera tigris) is a single species, but has several different populations:
Tigers in the same geographic area may breed with tigers from that area – these are populations.
Even though members of different populations do not usually breed with each other, they could breed with each other and produce viable offspring – therefore they are all the same species.
What is a generation?
A generation is a large group of living things that were . In organisms that give birth at approximately the same time of year, . An example is the reindeer (also called the ); these animals give birth in May and June every year. A generation is more difficult to define in organisms that reproduce year-round, like humans.
Review
Evolution is a in a population over time. In other words, if the in a population with a certain gene , the population has evolved. In our aardvark example, if the percentage of dark aardvarks compared to light aardvarks changes over time, the population is evolving.
How does evolution work?
There are several different ways that evolution can happen. The most common cause of evolution is called natural selection. The idea of natural selection was discovered by two people at almost the same time: Charles Darwin and Alfred Russell Wallace. Their idea was this:
In all living things…
More individuals are .
The that organisms need to survive (e.g. etc.)
There is a lot of (i.e. individuals are different from each other). A lot of the variation is based on genes.
If we combine these three ideas, we get another idea: there will be a amongst those individuals that are born – those individuals to compete for those resources will .
Over time the that cause organisms to be best suited to the environment will .
| |Example |
|More individuals are born than can survive | |
|Resources are limited | |
|There is variation in populations | |
| |Example |
|More individuals are born than can survive | |
|Resources are limited | |
|There is variation in populations | |
If enough time passes, the gene(s) that make living things best suited to their environment will become . How well an organism is adapted to its environment is called fitness. The will be more likely to survive and to the next generation.
For a long time people thought the Earth was than it actually is. Some religious texts imply that the Earth is . If the Earth was actually this old, there would not be nearly enough time for evolution to happen. However, from a number of different sources indicates that the Earth is . Current estimates of the Earth’s age are about (or about 4.6 billion years old), this number comes from the following evidence:
• The have been dated to about (found in Australia)
• Comparing the to other stars indicates that it is just over years old
• that have landed on Earth have been dated to 4.56 billion years (these meteorites, and the Earth, are part of the solar system)
Review
An easy way to remember the above the above steps is by the acronym VIST.
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Examples of Evolution Date:
Review: The acronym VIST is a way of remembering how populations evolve:
• Not all members of a population are ; i.e. there are variations in populations.
• Many of these differences are , which are inherited.
• Some members of the population have that allow them to , those without these genes do not; i.e. the ones with the gene(s) are selected.
• As time passes, the in the population changes.
Today we will look at 3 examples of evolution and see how VIST applies to each situation.
Example 1: Peppered moths in England
The peppered moth (Biston betularia) has been living in Great Britain for thousands years. Most moths are (sleep during the day, are active at night) and need to be while they sleep during the day. Most peppered moths have that allow them to be camouflaged on the trunks of trees; however some moths have a different that causes them to be . Most of these black-coloured moths would be while sleeping on trees, but enough of them survived to pass on the gene for black colour that there were always a few black-coloured moths.
The 1800s in England were a tough time – the age of industry was just beginning; up until this time there were no . However, as the industrial revolution began, large factories began to appear all over England, particularly in northern England around Manchester. These factories produced – so much that soot literally covered the landscape – trees were covered by so much soot that their .
In this ‘new’ environment, moths now had an advantage over the : predators could easily spot white moths on a black tree trunk, but the black moths were now much better camouflaged. Over a very short time the percentage of moths that were white and the percentage of moths that were black . Interestingly, the percentage of dark moths only increased , in other parts of England, the black moths remained relatively rare.
This is an excellent example of natural selection. Complete the VIST chart below for the peppered moth example.
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Example 2: Antibiotic-resistant microorganisms
Since the discovery of penicillin in 1928 by , antibiotics have been used to fight diseases caused by . Natural populations of bacteria contain, among their large number of individual members, in their genetic material, mostly as a result of mutations. When exposed to antibiotics, , but some have mutations that make them less susceptible (i.e. less likely to die). If the bacteria are exposed to the antibiotics for a short time (i.e. if you take your antibiotics for a short time) these individual bacteria will survive the treatment.
The surviving bacteria will reproduce again, the resistance to the antibiotics to their offspring. At the same time, , adding new genetic variation to the population. Spontaneous mutations are very rare, and advantageous mutations (i.e. mutations that are beneficial/good) are even rarer. However, populations of bacteria are that a few individuals will have beneficial mutations. If a new mutation makes them more resistant to an antibiotic, these individuals are more likely to survive when next confronted with that antibiotic.
Complete the VIST table below for the bacteria example:
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Example 3: Blackcaps in Europe
In a new research paper[3] authors have demonstrated that within the last thirty years, blackcaps (Sylvia atricapilla), which formerly overwintered in Spain and returned to central Europe in spring for breeding, have now divided into two groups that use different overwintering sites. One group continues its winter journey to Spain, but the other now overwinters in England. The authors speculate that a few decades ago some blackcaps found a rich feeding site in the UK, where the bird-loving public puts out plenty of food for the native species.
Since then, blackcaps in Europe go to either Spain or to England. Back at the breeding grounds, you can identify which bird went where by looking at the ratio of different isotopes in a small piece of the bird’s claws. (These isotope ratios identify what a bird has been eating: those overwintering in Spain eat mostly fruit, while the UK migrants live on seeds provided by aviphilic (bird-loving) Brits.)
The authors examined both genetic markers and anatomy of these two groups of migrating birds when they co-mingled on their common breeding grounds in Germany. There are two main findings:
1) There was a very slight but significant difference between the groups in their genetic markers, showing that they were not completely mixing their DNA on the breeding grounds each year. In other words, the two groups showed genetic evidence for weak reproductive isolation, which is how new species arise. (Two groups become separate species when they diverge (separate) so much that there is no mixing of genes between them.) This isolation probably stems from differences in mating of the two types: birds returning to Germany from the UK have to travel less distance, and show up on the breeding grounds earlier than their Spanish counterparts. That means that individuals who migrate to a given place tend to pair up with others from that place, simply because that’s who is around at mating time.
2) The two groups also differed in five anatomical traits: wing shape, head colour, body colour, bill colour, and beak shape. These differences may reflect strong natural selection that differentiated the birds since they began overwintering at different sites. (Selection for beak shape differences, for example, may reflect the different types of foods that each group has to handle in winter.) If these differences are genetic, then this also confirms some reproductive isolation between the two groups of birds.
So what does it mean? Well, it seems to show that in a very short period — only a few dozen blackcap generations — the gene pool of the birds has undergone some separation, although that splitting is by no means complete. Moreover, this division has happened without any geographic barriers keeping the two types apart. Both overwintering groups breed in the same place, and the “barrier” leading to genetic difference was caused by a behavioural change in the birds themselves, a change that may be genetic.
Complete the VIST table and questions for the Blackcap
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Questions
1. Where do blackcaps spend their summer?
2. Where did they all originally spend their winters?
3. How did researchers determine genetic differences between the two groups of blackcaps?
4. What two reasons are considered possibilities for why some blackcaps are now spending their winter in Britain?
5. Reproductive isolation is the most important requirement for a new species to arise, how might the two populations of blackcaps become reproductively isolated?
6. Can you think of another way new species could arise?
7. Many birds in Manitoba fly south for the winter. Think of a set of circumstances that could result in a similar event to the blackcap speciation happening here in Manitoba.
VIST Examples
Example:
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Glossary
|Term |Definition |
|Species | |
|Habitat | |
|Population | |
|Community | |
|Ecosystem | |
|Ecology | |
|Autotroph | |
|Heterotroph | |
|Detritivore | |
|Saprothrophs | |
|Consumer | |
|Trophic Level | |
|Food Chain | |
|Food Web | |
|Density-Dependent | |
|Density-Independent | |
|Bioaccumulation | |
|Interspecific Competition | |
|Intraspecific Competition | |
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Ecology Outcomes
|Code |Outcome description |Understanding Level |
| | |Level 1 |Level 2 |Level 3 |
| |Introductory |Demonstrate complete knowledge of 3 of the following: |Demonstrate complete knowledge of all the following: | |
| |material |Biological classification (KPCOFGS) |Biological classification (KPCOFGS) | |
| | |Hierarchy in biology |Hierarchy in biology | |
| | |Source of energy in ecosystems |Source of energy in ecosystems | |
| | |Definitions: |Definitions: | |
| | |Biology |Biology | |
| | |Ecology |Ecology | |
| | |Ecosystem |Ecosystem | |
| |Trophic levels |Describe 2 of the following: |Describe 3 of the following: |Describe all of the following: |
| | |Difference between consumers and producers |Difference between consumers and producers |Difference between consumers and producers |
| | |Kinds of consumers (e.g. herbivores) |Kinds of consumers (e.g. herbivores) |Kinds of consumers (e.g. herbivores) |
| | |Why food chains/webs have finite number of levels |Why food chains/webs have finite number of levels |Why food chains/webs have finite number of levels |
| | |Level of consumers (e.g. primary) |Level of consumers (e.g. primary) |Level of consumers (e.g. primary) |
| |Ecological pyramids |Describe the three “types of pyramids” |Describe the three “types of pyramids” |Explain differences and similarities in the three “types of|
| | |OR |Define and use the concept of “biomass” |pyramids” |
| | |Define and use the concept of “biomass” | |Define and use the concept of “biomass” |
| |Carrying capacity |Define the term “carrying capacity” and how it is useful |Define the term “carrying capacity” and how it is useful |Define the term “carrying capacity” and how it is useful |
| | |Explain TWO of the four factors that affect carrying |Explain THREE of the four factors that affect carrying |Explain the four factors that affect carrying capacity |
| | |capacity: |capacity |interspecific and intraspecific competition; |
| | |interspecific and intraspecific competition; |interspecific and intraspecific competition; |density-dependent and density-independent factors |
| | |density-dependent and density-independent factors |density-dependent and density-independent factors |Apply these concepts to real-life and hypothetical examples|
| | | |Apply these concepts to real-life and hypothetical examples | |
| |Population graphs |Be able to identify the three regions of a standard |Be able to identify the three regions of a standard |Be able to identify the three regions of a standard |
| | |population graph |population graph |population graph |
| | |Be able to make a population graph given sample data |Be able to make a population graph given sample data |Be able to make a population graph given sample data |
| | | |Be able to interpret population graphs (i.e. suggest |Be able to interpret population graphs (i.e. suggest |
| | | |possible reasons for trends shown on a graph) |possible reasons for trends shown on a graph) |
| | | | |Discuss the differences between open and closed populations|
| |Introduced species |Explain the impact of introduced species using specific |Explain the impact of introduced species using specific | |
| | |examples |examples | |
| | | |Discuss factors that explain why introduced species are | |
| | | |often so detrimental | |
| |Biodiversity |Explain the connection between biodiversity and |Explain the connection between biodiversity and | |
| | |sustainability |sustainability | |
| | |Explain the impact of human actions on biodiversity (present|Explain the impact of human actions on biodiversity (present| |
| | |and historical) |and historical) | |
| | | |Explain the phenomenon of biological accumulation (use a | |
| | | |real-life example) | |
| |Biogeochemical |Accurately describe the carbon cycle |Accurately describe the carbon cycle |Accurately describe the carbon cycle |
| |cycles |OR |Accurately describe the nitrogen cycle |Accurately describe the nitrogen cycle |
| | |Accurately describe the nitrogen cycle | |Discuss the impact of human activities on biogeochemical |
| | | | |cycles |
| |Ecological |Explain the phenomenon of ecological succession |Explain the phenomenon of ecological succession | |
| |succession |Explain the differences between primary and secondary |Explain the differences between primary and secondary | |
| | |biological communities |biological communities | |
| | | |Explain the importance of disturbance in many ecosystems | |
| | | |(with an example) | |
| |Introduction to |Complete 2 of the following 4: |Complete 3 of the following 4: |Explain the use of the term “theory” in science |
| |evolution |Explain the use of the term “theory” in science |Explain the use of the term “theory” in science |Include examples of other scientific theories |
| | |Include examples of other scientific theories |Include examples of other scientific theories |Define terms: “genetic make-up”, “population”, and |
| | |Define terms: “genetic make-up”, “population”, and |Define terms: “genetic make-up”, “population”, and |“generation” |
| | |“generation” |“generation” |Explain the relationship between “evolution” and “natural |
| | |Explain the relationship between “evolution” and “natural |Explain the relationship between “evolution” and “natural |selection” |
| | |selection” |selection” | |
| |Evolution part II |Explain the role of mutations in evolution |Explain the role of mutations in evolution |Explain the role of mutations in evolution |
| | |Use the “VIST” idea to explain how evolution works through |Use the “VIST” idea to explain how evolution works through |Use the “VIST” idea to explain how evolution works through |
| | |natural selection |natural selection |natural selection |
| | | |Use the peppered moth or antibiotic resistance examples to |Use the peppered moth or antibiotic resistance examples to |
| | | |explain natural selection |explain natural selection |
| | | | |Use a VIST table to explain a novel example |
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[1] source:
[2] From Wikipedia article “Evolution as theory and fact”. Accessed November 29th 2010.
[3]
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Cell
Organism
Organ System
Organ
Tissue
Biome
Ecosystem
Community
Population
Biosphere
A
B
C
=
+
+
Figure 2: The summer and winter habitats of the European Blackcap
Figure 1: A male European Blackcap
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