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What is Ecology??•The study of interactions that take place between organisms and their environment.

•It explains how living organisms affect each other and the world they live in.

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Habitat & Niche•Habitat is the place a plant or animal lives

•Niche is an organism’s total way of life

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The Nonliving Environment

•Abiotic factors- the nonliving parts of an organism’s environment.

•Examples include air currents, temperature, moisture, light, and soil.

•Abiotic factors affect an organism’s life.

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The Living Environment•Biotic factors- all the living organisms that inhabit an environment.

•All organisms depend on others directly or indirectly for food, shelter, reproduction, or protection.

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Levels of Organization

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What are the Simplest Levels?

•Atom•Molecule•Organelle•Cell•Tissue•Organ•System

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1st Level of Organization•Organism:

An individual living thing that is made of cells, uses energy, reproduces, responds, grows, and develops

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2nd Level of Organization•Population:

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

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Populations• Population Size

– Number of individuals in a population

– Affects population’s ability to survive

– Ex. Smaller populations are more likely to be endangered by random events such as natural disasters.

• Population Density– Number of individuals that live

in a given area.

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Population Growth• Populations grow when more

individuals are born than die in a given period.

• Population growth can be plotted on a graph.– Exponential Growth Curve

•Rate of population growth staysthe same, as a result the population size increases steadily.

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3rd Level of Organization•Biological Community:All the populations of different species that live in the same place at the same time.

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Symbiosis• SYMBIOSIS

– Interactions between species can become so intimate that one or both become dependent on the other•PARASTISM•COMMENSALISM•MUTALISM

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Parasitism• One species

benefits at the expense of the other.

• Ex. Leech sucking your blood!!!

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Commensalism• One species

benefits while the other is unaffected

• Ex. Epiphytes are plants that grow on trees. They do not harm or help the trees that live on.

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Mutualism• Both species benefit

• Ex. Insects and birds often eat the nectar made by flowers and while doing so they will get pollen attached to their feet. When they fly away they spread the pollen onto nearby flowers which aides in the reproduction of the plant.

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4th Level of Organization•Ecosystem:

Populations of plants and animals that interact with each other in a given area with the abiotic components of that area. (terrestrial or aquatic)

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Biomes• A major biological community that occurs over a

large area of land.– Examples

• Tropical Rainforest• Savannas• Deserts• Taiga• Tundra• Temperate Grasslands• Temperate Deciduous Forest• Temperate Evergreen Forest• Freshwater Communities• Wetlands• Shallow Ocean Waters• Surface of the open Sea• Ocean Depths

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Cycles in Ecosystems• Elements are recycled through

the environment– Carbon– Water– Nitrogen

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Water Cycle

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Carbon Cycle

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Nitrogen Cycle

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5th Level of Organization•Biosphere:The portion of Earth that supports life.

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The Biosphere

•Life is found in air, on land, and in fresh and salt water.

•The BIOSPHERE is the portion of Earth that supports living things.