Unit 5: the Interdependence of Organisms

UNIT 5: THE INTERDEPENDENCE OF ORGANISMS

Benchmark 1.13 (SOL-BIO1 and BIO9)

Students investigate and understand that the atoms and molecules on Earth cycle among the living and nonliving

components of the biosphere.

Indicators

1.13.1 Illustrate the interdependence of living things using the concepts of matter and nutrient cycling.

1.13.2 Explain how photosynthesis and cellular respiration are complementary processes for cycling carbon

dioxide and oxygen within an ecosystem.

Benchmark 1.14 (SOL-BIO1 and BIO9)

Students investigate and understand that energy flows through ecosystems in one direction, from photosynthetic

organisms to herbivores, to carnivores, and to decomposers.

Indicators

1.14.1 Illustrate the interaction of producers and consumers in an ecosystem with food chains, food webs, and

energy pyramids.

1.14.2 Explain how photosynthesis and cellular respiration are complementary processes for the

transformation of energy within an ecosystem.

Benchmark 1.15 (SOL-BIO1, BIO5, BIO7, and BIO9)

Students investigate and understand that organisms both cooperate and compete in ecosystems. The

interrelationships and interdependence of these organisms may generate ecosystems that are stable for hundreds

or thousands of years.

Indicators

1.15.1 Relate the concepts of individuals, populations, communities, and ecosystems to each other.

1.15.2 Illustrate the interactions within and among populations, including carrying capacities, limiting factors,

and growth curves.

1.15.3 Cite several examples of predation, parasitism, commensalism, mutualism, and competition.

1.15.4 Compare biotic and abiotic features of various terrestrial and aquatic biomes.

1.15.5 Illustrate the various succession patterns in ecosystems.

Benchmark 1.16 (SOL-BIO1, BIO5, BIO8, and BIO9)

Students investigate and understand that human beings live within the world's ecosystems. Increasingly, humans

modify ecosystems as a result of population growth, technology, and consumption. Human destruction of habitats

by direct harvesting, pollution, atmospheric changes, and other factors may threaten global stability and could

result in irreversible damage to ecosystems.

Indicators

1.16.1 Formulate ways of dealing with environmental problems such as air pollution and overpopulation.

------

Associated Laboratory Activities

Students should complete activities which enable them to:

5a. Understand the effects of population growth in relation to the ecosystem.

5b. Understand how energy passes from one trophic level to another as it moves through the ecosystem.

Glencoe

Text p. 86 Mini Lab How Can

You Create a Closed

Ecosystem?

Text p. 150 Biolab Degrading

Time of Packing Material

LM p. 129 INV 23-2 Which

Foods Can Bread Mold Use

for Nutrition?

Text p. 66 Biolab How Can

One Population Affect

Another?

Text p. 116 Biolab Population

Growth in Paramecium

LM p. 15 INV 3-2 The Lesson

of the Kaibab.

5a Effects of

Population Growth

Endangered Species :

Population Bottlenecks in

Mauna Kea Silversword Book 1

p. 73

Population Sampling : A

Simulated Field Study Book 1 p.

115

Exp. 21 Physical Profile of a Lake p. 21-1

Exp. 13 Population Dynamics p. 13-1

Exp. 18 Acid Rain p. 18-1

Ecology

First Look

Explorations: Introduction; Observing

Population Growth; Modifying Population

Growth; Two Populations: What's the

Difference?; Two Competing Populations;

Enter Predator; Maintaining a Balance

Core Inquiries: S and J Curves; Introducing

a Virus; Effect of Food Supply; Carrying

Capacity and Grass; Competition; Changing

Environmental Conditions; Predation; Eating

Efficiently; Survival Strategies;

Environmental Changes; Maintaining

System Balance; Competition Pressure

Independent Investigations: Design an

Animal; Design an Ecosystem; Global

Warming

5b Energy Flow

Within

Ecosystems

Counting and Coverage: A

Simulated Field Study Over

Time Book 1 p. 63

Exp. 14 Interdependence of Plants and

Animals p. 14-1

Exp. 19 Dissolved Oxygen in Water p. 19-1

Exp. 20 Watershed Testing p. 20-1

Exp. 22 Five - Day BOD p. 22-1

Exp. 25 Primary Productivity p. 25-1

Relevant Virginia Standards of Learning (SOL)

BIO.8 The student will investigate and understand how

populations change through time. Key concepts include

* examining evidence found in fossil records;

* investigating how variation of traits, reproductive

strategies, and environmental pressures impact on the

survival of populations;

* recognizing how adaptations lead to natural selection; and

* exploring how new species emerge.

BIO.9 The student will investigate and understand dynamic

equilibria within populations, communities, and

ecosystems. Key concepts include

* interactions within and among populations including

carrying capacities, limiting factors, and growth curves;

* nutrient cycling with energy flow through ecosystems;

* succession patterns in ecosystems;

* the effects of natural events and human influences on

ecosystems; and

·  analysis of local ecosystems.

Relevant Virginia SOL Review Questions

1. The study of how living things relate to each other and to their environment is called:

a. ecology *

b. mutualism

c. food web

d. commensalism

2. A relationship between two organisms in which both benefit is called:

a. commensalism

b. mutualism *

c. autotrophism

d. parasitism

3. A network of interconnected food chains is called a:

a. decomposer

b. food web *

c. biosphere

d. food chain

4. A relationship between two organisms in which one benefits and the other neither benefits nor is harmed is

called:

a. mutualism

b. parasitism

c. decomposer

d. commensalism *

5. The layer of Earth that supports life is:

a. ecology

b. the habitat

c. the biosphere *

d. trophic levels

6. An organism that feeds on dead organisms is a:

a. scavenger *

b. parasite

c. herbivore

d. plant

7. A simple model for showing how matter and energy move through the ecosystem is a:

a. trophic level *

b. food web

c. habitat

d. food chain

8. An organism that manufactures food using energy from the sun or from chemical compounds is a:

a. heterotroph

b. decomposer

c. autotroph *

d. parasite

9. The role an organism has in the environment is called:

a. ecology

b. the biosphere

c. a habitat

d. a niche *

10. An organism that obtains energy from breaking down dead organisms is called a:

a. parasite

b. autotroph

c. carnivore

d. decomposer *

11. Which is not recycled in the biosphere?

a. water

b. energy *

c. oxygen

d. all of these are recycled

12. The largest biome is the:

a. tundra

b. coniferous forest

c. desert

d. ocean *

13. The greenhouse effect is due to a buildup of:

a. nitrates

b. water vapor

c. carbon monoxide

d. carbon dioxide *

14. A prey population usually decreases as the predator population:

a. increases *

b. decreases

c. immigrates

d. stays the same

15. All the possible food chains in a habitat are called:

a. a niche

b. a food web *

c. a trophic level

d. a community

16. Limiting factors keep populations from:

a. declining

b. emigrating

c. getting too large *

d. getting too small

17. Which of the following shows the correct order of a food chain?

a. primary consumer-> producer-> secondary consumer

b. secondary consumer-> producer-> primary consumer

c. producer-> primary consumer-> secondary consumer *

d. producer-> secondary consumer-> primary consumer

18. Which type of organism is not shown in the following representation of a food chain? grass--> mouse-->

snake--> hawk

a. herbivore

b. decomposer *

c. producer

d. carnivore

19. Phytoplankton --> Zooplankton --> Mussels --> Starfish

What effect would harvesting the mussels have on this food chain?

a. The carbon dioxide levels in the water would decrease.

b. The oxygen levels in the water would decrease.

c. The starfish population would increase.

d. The zooplankton population would increase. *

20. Aerobic organisms are dependent on autotrophs. One reason for this dependency is that most autotrophs

provide the aerobic organisms with:

a. oxygen *

b. carbon dioxide

c. nitrogen gas

d. hydrogen

21.The pictures show the results of allowing bread mold in a sealed jar for a week. Which of these best explains the

lack of change in mass in this demonstration?

a. Water evaporated from the bread at the same rate mold grew on it.

b. Materials are recycled in closed environmental systems. *

c. Populations in closed systems grow until the food supply is gone.

d. Some of the mold is dying.

Organisms, Ecosystems, and Population Growth: Interrelationsips

and Interdependencies

NSES Generalization

Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these

organisms may generate ecosystems that are stable for hundreds or thousands of years.

Living organisms have the capacity to produce populations of infinite size, but environments and resources

are finite. This fundamental tension has profound effects on the interactions between organisms.

Human beings live within the world’s ecosystems. Increasingly, humans modify ecosystems as a result of

population growth, technology, and consumption. Human destruction of habitats through direct harvesting,

pollution, atmospheric changes, and other factors is threatening current global stability, and if not addressed,

ecosystems will be irreversibly damaged.

Further Description

The organization of ecosystems is based upon populations interacting with each other and with abiotic

factors of the environment. The interaction of populations sets up a community. Populations may interact in

positive or negative ways. An example of a positive interaction is seen in the pollinating activities of

flowering plants. In this symbiosis, the flower is fertilized while the pollinator collects its food.

Predator-prey relationships show a positive as well as negative association. Competition for resources can

also cause negative interaction. In this case the population most affected by the competition is eliminated

from a niche. Because of these interactions, numerous adaptations have evolved that prevent elimination of

populations from a selected ecosystem. Species have adapted to be able to coexist with each other by

sharing resources, reducing competition, and entering into positive symbioses.

In any community, populations will tend to replace each other in an orderly process. This is due to the fact

that habitat populations change. Use of nutrients and other "abiotic" factors by resident populations causes

habitats to change, resulting in a replacement process, or succession. This process of community change results in a

series of transitory communities until a final or mature community is established. Given sufficient time and stability of

biotic and abiotic factors, a climax will be reached. The climax community can last for hundreds of years

uninterrupted.

All populations have an inherent tendency to increase in size. This potential increase is extremely high for most

species. This type of exponential growth begins slowly and then continues on a rapid incline as more reproductive

individuals are produced each generation. Control of population growth is based upon limiting factors and population

interactions in each ecosystem. Resources such as food, water, oxygen, and space availability, as well as predation,

competition, and parasitism, place environmental limits on population growth. These limits set the carrying capacity of

the ecosystem. Population size will oscillate around this carrying capacity. When a population exceeds carrying

capacity, a strain upon resources could result in a sharp decline in the population.

Human civilization has brought about dramatic changes in the ecosystems of the world. These changes have resulted

in major environmental problems, which in turn directly affect the survival of all species on Earth. Because of

agricultural practices, technological advances, and medical triumphs, world population growth has reached a size well

over 5 billion. This "population explosion," coupled with a lack of understanding of ecological principles, has

resulted in massive pollution of land and water, destruction of habitats and loss of bio-diversity, possible

climate changes that could result in global warming, and penetration of the protective ozone layer shielding all

life from harmful UV rays. Policy decisions facing planet Earth should focus on population control, recycling of

human waste, and development of alternative energy sources, and should develop a better understanding of the

human impact on ecosystem balance.

Concepts Needed

Grade 9

Population, community, niche, habitat, competition, ecosystem, limiting factors, exponential growth mortality

Grade 10

Succession, serial stages, ecotone, pioneer species, climax communities, associations, community

Grade 11

Symbiosis, predator-prey, mutualism, amensalism, commensalism, parasitism, succession, biotic potential,

agriculture, technology, human population growth form, biodiversity, layers of the atmosphere, waste disposal,

fossil fuels, recycling, pesticides, pollutants, endangered species, abiotic factors

Grade 12

Density-dependent and density-independent factors, carrying capacity, acid rain, ozone depletion, succession,

climax concept

Empirical Laws or Observed Relationships

Interdependence, population levels of species fluctuate with environmental conditions

Theories or Models

Competitive exclusion principle, equilibrium hypothesis of island biogeography, climax communities, facilitation

hypothesis, inhibition hypothesis, J-shaped and S-shaped growth form, age distribution pyramids, r and K

strategies, global warming, succession

Cycles in the biosphere and Energy Flow through Ecosystems

NSES Generalization

The atoms and molecules on the earth cycle among the living and nonliving components of the biosphere.

Energy flows through ecosystems in one direction, from photosynthetic organisms to herbivores to carnivores

and decomposers.

Further Description

The cycling of nutrients in any ecosystem is essential to maintain a balance in that ecosystem. Ecosystems

are dependent upon resources that are used by organisms and the recycling of wastes disposed by them.

Essentially the same atoms and molecules are being used over and over again. Nutrient cycling of organic

and inorganic substances takes place in all ecosystems. Nutrients critical for maintaining homeostasis in

any ecosystem are carbon, nitrogen, and phosphorus.

The carbon cycle begins with atmospheric CO2 , which is absorbed by plants. CO2 is fixed through

photosynthesis into glucose, which is used by all organisms in respiration to produce ATP. In respiration,

CO2 is released as a waste product and sent back to the atmosphere. This cycle sets up the basic food chain

for all ecosystems. CO2 is released into the atmosphere through decomposition and combustion as well,

adding to the reservoir of CO2 necessary to continue this cycle.

The nitrogen cycle is based upon the action of the decomposers in soil. Decomposers have the ability to

convert nitrogen wastes and dead organic matter into a usable form for plants. In addition, a special group