Topic 6

Friday, June 6, 11:34:02 Friday, June 6, 11:34:02 AMAM

Topic 6Topic 6

EcologyEcology


The environment is every living and nonliving thing that surrounds an organism


Ecosystem describes any portion of

the environment


All the living things in an ecosystem are

called biotic


Non living influences are

called abiotic factors


The specific environment in which

organisms live is their habitat


All the organisms of a species that live in the same area make up a

population


All the different populations are combined to form a

community


Collectively all of the Earth’s ecosystems make up the

biosphere


The fundamental concept of ecology is that all living organisms are

interdependent, and they interact with one another and with the physical environment


Competition is the struggle for resources among organisms


Factors in the environment that limit the size of populations are known as

limiting factors


Predators kill and eat other organisms


Prey are killed for food


The number of organisms of any single species that an ecosystem can support is referred to as its

carrying capacity


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The role that each species plays in the

ecosystem is called its ecological niche


In predator – prey relationships food chains show what eats what


Photosynthetic organisms make their own food. They are

known as autotrophs or producers


Heterotrophs must acquire food by consuming other organisms. Heterotrophs are also called

consumers


Herbivores are heterotrophs that survive on plant tissues


Carnivores are heterotrophs that eat other animals


The wastes and dead bodies of all organisms are

consumed by decomposers


Scavengers are consumers that eat dead organisms they do not kill


Parasites are organisms that attack other live

organisms (called host organisms) but rarely kill them


Food webs are diagrams that show more complex feeding relationships


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Almost all organisms use

the solar energy (the sun) in food to power their life processes


1000 Calories

990 Calories lost to the environment

10 Calories of plant matter available as food

1 Calorie available as food

9 Calories lost to the environment

As energy is transferred, much of it is

lost to the

environment


An energy pyramid is a diagram that illustrates the transfer of energy through a food web or chain


Herbivores

Carnivores

Producers


Release of oxygen

(photosynthesis)

Release of carbon dioxide Dead animals

Decom

posit

ion

nutrients


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Biodiversity is a measurement of the degree to which species vary within an ecosystem


Many species may be lost when natural disasters cause large scale destruction to habitats


Species can also be lost when humans do not consider the environmental impact of their action


Endangered species


Biodiversity also represents one of the greatest resources known to

humans. Medicinal herbs and plants are one example


The series of changes by which one habitat changes

into another is called ecological succession


Climatic changes, natural disasters, and the activities of animals (including humans) can alter stable ecosystems


View the process of ecological succession as it occurs in coastal lowlands by clicking on the image

below

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Topic 6