Hand-out 1: Ecology for Benildeans



Hand-out 2: Ecosystem Ecology (Part 2)

Support Mechanisms: Energy Flow, Food Chain, Food Web, 10% Law, The Law of Thermodynamics.

Chemical Recycling: Water, Carbon, Nitrogen, Phosphorus

Human Intrusions: Biomagnification, Cycle Disruption, Water Depletion, Eutrophication, Deforestation

Lecturer: Mr. Jose Mari Balines Gonzales

M.Sc. in I.T for Natural Resources Management

Objectives:

• To illustrate the correlationships of selected functional components that supports the ecosystem.

• To examine the varying benefits that can be derived from chemical recycling.

• To assess and refine existing human activities that involves tampering with essential support mechanisms of the Philippines ecosystems.

Introduction

As development of the natural landscape proceeds, arguments over land use emerge. Change in land use will bring benefits. However, changing one facet brings repercussions throughout the ecosystem.

The image on the right is a dipterocarp forest in West Kalimantan, Indonesia undergoing conversion to plantation. The tropical forests of Indonesia represent one of the most biologically diverse regions on earth, as well as a significant terrestrial reservoir for atmospheric carbon. However, the ability of dipterocarps to reproduce, sustain animal populations and absorb carbon in the atmosphere are now being disrupted by habitat fragmentation. (Curran, 2003) The same is occurring here in the Philippines.

Important Abiotic Factors

1. Temperature

• Important in controlling the rate of body processes in an organism.

▪ The higher the body temperature the faster the rate of body processes.

• 3 Sources of Heat:

1) Solar radiation.

2) Heat radiation from surroundings (underground and other organisms).

3) Metabolism

2. Moisture

• Important for biochemical processes in a species’ body.

3. Light

• Important for photosynthesis.

4. Soil

• Loose surface material of land in which plants grow.

• Important medium for plant growth.

5. Fire

• Important for removing plant cover, removing litters and enhances mineral availability in soil.

Energy Flow

• Energy comes to Earth in the form of light.

• Converted to chemical energy through photosynthesis.

• Complies with the Laws of Thermodynamics:

1. Energy can be transferred from one state to another; none is lost (or destroyed).

2. As energy is converted from one state to another, the quality of the energy deteriorates.

• Energy flow (Fig.5-2):

[pic]

Chemical Recycling

• Living things need the following atoms (or nutrients) for their cells:

Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Sulfur (S) and 20 other atoms.

• Because of the interaction of the lithosphere, hydrosphere and atmosphere, these atoms/nutrients are made available to every living organism in the biosphere.

• These atoms/nutrients flow in an ecosystem following this general pattern (Fig.5-3):

Biogeochemical Cycles

(See Appendix A for illustrations)

1. Carbon-Oxygen Cycle

• Carbon is needed to create amino acids, proteins, DNA (deoxyribonucleic acid), and cellulose.

• Present in the atmosphere as carbon dioxide (CO2), a gas.

• Carbon is present in the atmosphere and stored by plants.

• Respiration is a cell process that enables consumers and decomposers to return CO2 back to the atmosphere.

2. Nitrogen Cycle

• Although consumers need nitrogen, plants need it more for plant growth.

• However, plants cannot easily get nitrogen from the atmosphere.

o It has to be “fixed” (converted or prepared) by nitrogen-fixing bacteria found in the soil.

3. Phosphorus Cycle

• Phosphorus is important to make phosphate molecules (an important component of DNA).

• It is stored in rocks. Plants absorb it through water when washed phosphorus is washed away or released from the rocks through weathering.

4. Hydrologic Cycle

• Water is an essential medium for chemical processes for living and non-living components of the ecosystems.

• How much water does Earth have for living organisms (Fig.5-4)?

Human Intrusions

• Intrusion: the act of wrongfully entering upon

seizing

taking possession of the property of another

(Webster’s New Collegiate Dictionary, 1976)

• Human intrusions brought about by:

1) Changing lifestyles.

- Hunter ( Gatherer ( Urban Dweller

2) Perspective of the world.

- We always prioritize our needs over other species.

- No sense of accountability.

3) Rapid and expanding human population growth.

Biomagnification (See Appendix B)

• Chemicals (pesticides) and radioactive isotopes persist in an organism’s cell or tissue. Through the food chain, it accumulates to the succeeding consumers.

• Chemicals and radioactive isotopes persist because they are new to the body and could not be broken and excreted.

Cycle Disruption

• Interrupting certain portions of a biogeochemical cycle.

• Primarily results to pollution.

A. Water Depletion

• Will eventually affect sanitary requirements, availability of clean water, industrial needs, etc. among some of the human activities.

• Will affect water requirements of other species.

B. Eutrophication (See Appendix B)

• It is a process of fertilizing a body of water that affects growth rates and chemical cycles.

• It results from increasing the availability of N and P in the system.

• Lakes naturally undergo eutrophication as they age, which is slow and would take thousands of years.

• Humans can induce eutrophication overnight, which is already a form of pollution.

o Humans can induce this by:

a) Fertilizers on land washed by water to a body of water.

b) Fertilizers on land carried by soil erosion.

c) Human sewage.

d) Industrial activities.

C. Deforestation

• It is an act of clearing forest areas.

• Human beings resort to this act because of:

a) Expansion of human population.

b) Extreme poverty.

c) Changes in land management.

d) Demand for hard wood.

E N D

References:

Brewer, R. 1994. The Science of Ecology, 2nd Ed. Saunders College Publishing, USA.

Bush, M.B. 1997. Ecology of A Changing Planet. Prentice Hall, Upper Saddle River, New Jersey

Chambers 20th Century Dictionary. 1983. W & R Chambers Ltd. Edinburgh, Great Britain.

Curran, L. 2003. Land Cover and Land Use Change in West Kalimantan, Indonesia: Implications for Carbon Dynamics and Biodiversity. Department of Geography, University of Maryland, College Park, USA.

Enger, E. and Smith B. 2006. Environmental Science: A Study of Interrelationships, Tenth Edition. McGraw-Hill Companies, Inc. New York, USA.

Appendix A

Downloaded Diagrams of the Biogeochemical Cycles

(Diagrams are all downloaded using the Google search engine, 2006)

1. Carbon-Oxygen Cycle (2006, Science Clarified)



[pic]

2. Nitrogen Cycle (2006, US Environmental Protection Agency)



[pic]

3. Phosphorus Cycle (2006, free webpages)



[pic]

4. Hydrologic Cycle (2006, Biology Web Site References for Students and Teachers)



[pic]

Appendix B

Downloaded Illustrations of Some Human Intrusions

(Illustrations are all downloaded using the Google search engine)

1. Biomagnification: Polychlorinated Biphenyls (PCB) (2006, New York Dept. of Environmental Conservation)



[pic]

2. Eutrophication (2006, British Broadcasting Co.)



[pic][pic][pic][pic][pic][pic][pic][pic][pic]

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Figure 5-2. The energy that flows through an ecosystem come and start from the Sun, then flows through the food chain. How do you think can energy get out of the seemingly endless flow? What do you notice with the amount of energy that is transferred from one consumer to another?

Ecosystem mechanisms in the forests of West Kalimantan, Indonesia are being disrupted by habitat fragmentation through land use conversion. What do you think are the implications environmentally and socially? The same is happening here in the Philippines. (Image downloaded from Google search engine)

Figure 5-4. Most references estimate that we have this much fresh water in our planet- with only a few amounts readily accessible to humans and other species. Why should we be alarmed by this figure?

0.04% in lakes and rivers

2.6% as freshwater

20% in groundwater

Water

80% in ice caps

97.4% in oceans

Figure 5-3. Atoms, or nutrients, are constantly recycled in the biosphere to allow other organisms to exist and develop. Where do you think the atoms and molecules that make up your body come from?

Class Activity 2: What is a Food Chain?

Film Viewing: “What is A Food Chain?” This film will give you an idea on the kind of food chain that exists in marine ecosystems. While viewing the film take note of the following:

• How is the food chain in a terrestrial ecosystem different with that in a marine ecosystem?

• Why do you think is the food chain in marine ecosystems more fragile compared with that in terrestrial ecosystems?

Instructions:

1. Work individually.

2. Write an insight paper about the film.

3. Specs:

a. 1 short bond paper.

b. Font size: 12

c. Font type: Times New Roman

d. Spacing: single

4. Submit your paper next meeting.

➢

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Natural Science 13 DLS – College of Saint Benilde

Hand-out 2: Ecosystem Ecology (Part 2)

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