Science 10AP: Nutrient Cycles in Ecosystems



Science 10 Enriched: (3.1) How Changes Occur Naturally in Ecosystems

Name:

Date:

HOW ORGANISMS ADAPT TO CHANGE

• How do living organisms change?

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▪ Why is change important?

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Ex. _____________________________________________________________________

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• Natural selection: ________________________________________________________________________________________________________________________________________________________________________________________________________________________

◆ Those with unfavourable characteristics: ______________________________________

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▪ Ex._______________________________________________________________

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▪ Complete Activity 3-1A Adaptations to Aquatic Environments.

Complete the ‘what to do’ section of this activity.

|Structure |Adaptation |Advantages to the organism |

|Body |1. | |

| |2. | |

| |3. | |

| |4. | |

|Mouth |1. | |

| |2. | |

| |3. | |

| |4. | |

| |5. | |

| |6. | |

|Eyes |1. | |

| |2. | |

| |3. | |

|What did you find out? |

|Use this page with Find Out Activity 3-1A, Adaptations to Aquatic Environments, on page 109 of your student book. |

[pic]

| |Feeding Behaviour? |Fast or Slow Swimmer? |Deep Water, Shallow Water, or Bottom Dweller?|

| |How Do You Know? |How Do You Know? |Why? |

|1 | | | |

|2 | | | |

|3 | | | |

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|6 | | | |

|7 | | | |

Adaptive radiation: __________________________________________________________________________________________________________________________________________________.

◆ The new species are adapted to inhabit _____________ niches.

▪ Example 1: ________________________________________________________________

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◆ How are the finches different? Why are they different? _____________________________

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◆ There are _____ species of finch on the Galapagos Islands.

◆ It is believed that each is descended from ________________________________________

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▪ Example 2: _________________________________________________________

◆ The more than ______ species of cichlid fish that once inhabited Lake Victoria in Africa are believed to have originated from a single species.

▪ Example 3: _________________________________________________________________

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How Ecosystems Change Over TimE

• Ecosystems are continually ___________________.

• The types of species that live in an ecosystem change as the ___________ factors in the ecosystem change.

Ecological succession: ____________________________________________________________________________________________________________________________________________________.

There are two types of ecological succession:

1. ______________________________________

2. ______________________________________

1. Primary succession - ____________________________

◆ Occurs after natural events such as when ____________________________________________________________________________________________________________________________________________________

◆ Wind carries spores of ____________ and organisms that can survive and eventually, combined with the weathering of rock, help form ________.

◆ pioneer species: __________________________________________________________________________

▪ Pioneer species alter the abiotic and biotic environment in a variety of ways: ____________________________________________________________________________________________________________________________________________________

General model of primary succession (Fig. 3.8):

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▪ ____________________________________________________________________________________________________________________________________________________

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▪ ______________________________________________________________________________________________________________________________________________________________________________________________________________________________

▪ ______________________________________________________________________________________________________________________________________________________________________________________________________________________________

▪ __________________________________________________________________________

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Mature communities

• aka _________________________________________

• Examples include:

◆ _________________ forest form in the northern latitudes.

◆ ________________ forest form in temperate zones.

◆ ______________ forest form in tropical zones.

• _____________ and _______________ are also examples of climax communities.

• Mature communities may appear to be stable and unchanging over long periods of time but they are always changing due to _________ ___________________.

◆ scientists prefer the term mature community because it reflects that the forest is _________________ _____________.

2. Secondary succession - _______________________________________________________________________________________________________________.

◆ ____________ _________ are the most common reason for secondary succession.

◆ The soil remains for plant growth, and contains seeds, micro-organisms, earthworms and insects.

◆ Secondary succession is much ___________ than primary succession.

◆ There is already soil, seeds and insects, so it only lasts _____________.

Do activity 3-1B Modelling succession in ecosystems.

◆ Use the table below to complete part 1, number 1.

|Pond Succession |Ocean Sand Dune Succession |

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How Natural Events Affect Ecosystems

Many other large disturbances can affect mature communities.

Flooding

◆ Occurs when _______________________________________________________________ ____________________________.

◆ Generally occurs in locations where water levels can change _______________.

◆ It can result in __________________________, and ___________________________and _______________________________ from harmful bacteria associated with wastes.

◆ ___________________________ may be increasing incidents of flooding.

Tsunami

◆ ________________________________________________________.

◆ Caused by ____________________________________________________________

◆ Plants and animals are _____________________ or ________________, or cannot survive in the resulting ___________ soil.

Drought

◆ Occurs when _______________________________________________________________ __________________________________________________________________________.

◆ Prolonged drought can destroy ________________, result in ________________________ and ___________________________.

Insect infestations

◆ Insects: ___________________________________________________________________

_________________________________________________________________________.

◆ Even insects that appear destructive, such as the ____________________________, actually play a role in the renewal of the forest.

▪ How so? ___________________________________________________________________

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◆ However, when normal conditions are changed, _________________ can occur.

▪ How so? ______________________________________________________________________

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▪ A ____________ climate, and lack of ________________, allows the insects to spread much more effectively than in the past.

◆ What is affected? ____________________________________________________________

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