LEC. Biology EcosystemsBenchmark 1

Describe common ecological relationships betweenand among species and their environments.

“Ecology is the study of the interrelationships among all living organisms (biotic) and the nonliving elements (abiotic) in and affecting our world. Biotic components

live and die; most abiotic components are in a continuous cycle of building up and being reduced. These ebbs and

flows make life possible by seeking a balance among all components, living

and nonliving.”

http://www.windowsintowonderland.org/fire/teachers/fireecology.htm

CompetitionTerritory

Carrying capacityNatural balance

PopulationDependence

Survival

Biotic Factors

Abiotic factors

Key concepts

Each species is sensitive to changes in abiotic interactions which influence the development of the community and the

stability and persistence of community is influenced by biological interactions. The interactions between species

may be competition for space or as the result of survival, Migration. For example, species BZ may have a negative effect upon species LM. If species BZ is

parasitic, then it depends on the presence of other species as hosts or partners. Environmental changes

removing the host species will cause species BZ reliant on them to disappear.

http://www.ukmarinesac.org.uk/communities/intersand-mud/ism4_3.htm

Biotic Factors Abiotic Factors

Ecosystems consist of many factors.

Non-living componentsLiving components

water, sunlight, temperature, pH

plants, animals (including humans)bacteria

The Biotic and Abiotic Factors affect each other: for example an abiotic factor like pH in

soil affects the growth of plants in that soil.

A woman’s work is

…never done!

“The balance of nature is disturbed when even a single organism is removed

or added within a community because a community is a group of interacting species in a given area. Everything in the community is dependent on each

other; they are all connected. The relationships may be positive

or negative, but any alteration results in change.”

http://www-personal.umd.umich.edu/~jlcarlso/communityecology.htm

Populations and Carrying Capacity

http://www.dnr.state.wi.us/org/land/er/publications/wolfplan/figures/figure_7.htm

Animals that live in packs or herds andplant colonies, such as:

wolves, bison, lilies and other bulb plantsvarious forms of algae

Real-world contexts

http://www.autumnsongart.com/photography.htm

Question One

Question Two

Question Three

Which one(s) of the following would be considered an abiotic factor?

a) Elm tree

b) Water

c) Rock portion of soil

d) Rabbit

e) Temperature

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Any living organism or materials coming from

living things are considered biotic.

Abiotic factors are those that were never living…

Any living organism or materials coming from

living things are considered biotic.

Abiotic factors are those that were never living…

Identify which of the following factors would cause the carrying capacity to increase for a population and which would cause it to decrease.

1. Increasing food supply

2. Increasing drought

3. Increasing predators

4. Increasing pollution

5. Increasing sunlight

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1. Increase-more food would cause the population size to increase

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2. Decrease-decreasing rain would cause plants to die then animals

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3. Decrease-increasing predators would hunt and kill members of the population

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4. Decrease-pollutants will harm or kill members of the population

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5 Increase-more sunlight will promote plant growth which will increase the population size of other members.

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In an ecosystem, there are populations of bobcats, rabbits and grass. Bobcats eat rabbits and rabbits eat grass. Indicate what would happen to the other two populations given the following:

1) Decreasing grass populations due to drought

2) Disease kills all of the bobcats

3) Rabbits population begins to increase uncontrollably

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1. The population of rabbits would begin to starve then the bobcat population would have less food and their population would go down

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2. Without the bobcats, the rabbit population would increase. More rabbits would eat more grass causing the population to decrease

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3. With more rabbits, the grass population would go down but the bobcat population would go up.

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