Levels of

Organization

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Organism

Organism

An individual living thing that is made

of cells, uses energy, reproduces,

responds, grows, and develops

Organisms compete for food, water,

shelter, and mates

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R-strategist

• Reproduce early in life, have many offspring, no parental care, short life span

• Examples: roaches, mosquitos, ants

4

K-strategists

• Reproduce later in life, have few offspring, show parental care, long life span

• Examples—humans, elephants, dogs, cats

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Population

A group of organisms, all of the same species, which live in the same place at the same time and interbreed

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Population vocabulary

• Population size: the number of individuals

• Population dispersal: how they are distributed

• Population density: the # of individuals in a given area

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Community

Collection of all populations of different species that live in the same place at the same time.

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Habitat & Niche

• Habitat is the place a plant or animal lives

• Niche is the role the organism plays in the community

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Fundamental niche

• All of the possible roles an organism could fill in a community

• All the resources it COULD use

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Realized niche • The part of the fundamental niche the

organism actually uses

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Ecosystem

• Populations of plants,

animals, and micro-

organisms that interact

with each other in a

given area and with

the abiotic

components of that

area.

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Ecosystem Components

• Biotic factors- all the living organisms that inhabit an environment

• Abiotic factors- the nonliving parts

of an organism’s environment Examples: air currents, temperature,

moisture, light, and soil.

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Biomes • Terrestrial (land based) include the 7

major biomes

–Tundra --Desert

–Taiga --Tropical forest

–Temperate grassland

–Temperate forest

–Savanna

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• Aquatic –Freshwater—streams, lakes,

ponds, rivers

–Wetlands-swamps, estuaries

–Marine-oceans (75% of the Earth’s surface)

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Biosphere

The portion

of Earth that

supports life.

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