ECOSYSTEMS

ECOSYSTEMS & ECOLOGY Ecology is the

study of the interactions of living organisms with one another and their physical environment.

ECOSYSTEMS & ECOLOGY

A population consists of all of the individuals of one species that live together in the same area.

A community is all of the different populations (different species) that live together in a defined area.

ECOSYSTEMS & ECOLOGY

An ecosystem is made up of a community plus all of the physical aspects of the environment (like soil, water, sun, etc.)

ECOSYSTEMS & ECOLOGY A biome is a

group of ecosystems that have the same climate & similar communities.

ECOSYSTEMS & ECOLOGY

The biosphere is the entire living earth, where life exists, including land, water & air.

ECOSYSTEMS & ECOLOGY The place where an organism lives is its

habitat. An organism’s niche is its place (role) in

the ecosystem, including how it fits into the food web, the environmental conditions it needs in order to live & how it reproduces.

No 2 species share exactly the same niche in the same habitat.

ECOSYSTEMS Abiotic factors – are all of the nonliving

parts of an ecosystem (like weather, soil, gases and water).

Biotic factors – are all of the living parts of an ecosystem (like bacteria, protists, fungi, plants and animals).

Energy Flow through Ecosystems

Energy flows through an ecosystem in one direction: SUN AUTOTROPHS HETEROTROPHS

Heterotrophs include animals such as carnivores, herbivores and omnivores.

Sunlight is the main source of energy for all life on Earth.

Energy Flow through Ecosystems

Producers (Autotrophs): Organisms that capture energy from the sun and turn it into food.

Energy Flow through Ecosystems

Consumers (Heterotrophs): All animals that obtain energy by eating producers.

Energy Flow through Ecosystems

Every organism in an ecosystem is assigned to a trophic level, which is determined by the organism’s source of energy (food sources).

Energy Flow through Ecosystems 1st trophic level:

Producers – plants, algae & bacteria 2nd trophic level:

Herbivores – All animals that eat plants 3rd trophic level:

Carnivores – All animals that eat herbivores (omnivores eat both plants & animals).

4th trophic level: Top carnivores – Carnivores that eat other carnivores

Energy Flow through Ecosystems

Decomposers: Organisms that break down organic matter (Example: fungi and bacteria)

Energy Flow through Ecosystems

A food chain shows one path of energy flow in an ecosystem. Most ecosystems support more than one food chain and they generally interweave into a food web.

Energy Flow through Ecosystems

Energy Flow through Ecosystems The amount of energy in an ecosystem

can be represented by an ecological pyramid.

Each trophic level contains less available energy than the level below it, so there are always fewer organisms in the higher levels of the food chain.

Energy Flow through Ecosystems

Only about 10% of the energy available is within one trophic level is passed on to the next trophic level.

Succession Natural changes in the physical

environment of ecosystems happen all the time.

EXAMPLE: When a volcano forms a new island or fire burns all of the vegetation in an area and a new habitat is created.

Succession As an ecosystem changes, older

inhabitants gradually die out and new organisms move in.

Succession These changes in plant and animal life

that occur in a community over time are called ecological succession.

Stages of Succession in a Pond

Succession When succession occurs on land where

nothing has grown before it is called primary succession (Example: The invasion of plants from water to land)

When succession occurs in areas where there has been previous growth it is called secondary succession (Example: A fire wipes out the entire plant & animal life in a forest and several years later new plants & animals are present.

Community Interactions Community interactions refers to the ways

that animals and plants relate to each other. Competition occurs when organisms

compete for resources such as water, food, light or space.

Usually competition results in a winner and a loser, often with the losing organism’s failure to survive.

Coevolving in Opposition

Predation: When one organism (the predator) feeds on another organism (the prey).

Symbiosis Symbiosis

occurs when two species live closely together in relative harmony.

MUTUALISM Mutualism is a type of symbiosis that

occurs when both organisms benefit from their association with each other.(Example: Lichens, Rhinos & tick bird)

COMMENSALISM Type of symbiosis

in which one species benefits from an association and the other species is neither helped nor harmed.

Example: Barnacles are organisms that attach themselves to whales to obtain a free ride to food sources, while the whale is unaffected by their presence.

Coevolving in Opposition Parasitism: A special type of

predation where one organism (the parasite) lives in or on another organism (a host) and causes the host harm.

Parasites usually do not intentionally kill their host since they depend on it for food, but often the host is fatally harmed by this association.

ECOSYSTEMS

Limiting factor:Any factor that restricts the existence or number of organisms. (See the examples at right:)

ECOSYSTEMS

Carrying capacity – The maximum number of individuals that an environment can support. As resources become less available, the growth of a population tends to slow or stop.

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