Ecology 1

Levels of Organization in Ecology Ecologists study individual organisms, but this only provides part of the story of its life cycle. An individual organism interacts with others of its species; it is also dependant on other organisms for food, shelter, reproduction and protection.

The distribution patterns of species If an animal survives for a long time in a particular community it must be able to reproduce there. A large number of biotic and abiotic factors influence how an animal or plant species may interact and change with time.

What is ecology? The word ecology comes from the Greek for “house”. Why do you think this is appropriate?

Levels of Organization 5

Levels of Organization in Ecology cont. Biome – a large region characterized by a specific climate and certain plants and animals Biosphere – the portion of Earth that supports life The biosphere extends from high in the atmosphere to the bottom of the ocean.

The volume of the earth’s surface where organisms can be found. It extends from the depths of the ocean (11km below sea level) to at least the highest plant communities (6.2km) Biosphere

Biome The biosphere is made up of several types of biome. These are classified due to their major vegetation types, for example TUNDRA or TROPICAL RAINFOREST.

An Ecosystem is a part of a biome. Biomes themselves are far too large to study so ecology work tends to be based around a particular ecosystem. Each ecosystem has a characteristic set of plants, animals and microbes. The organisms in an ecosystem form a self-sufficient unit in balance with their environment. Ecosystem

This is a group of species that occurs at the same place at the same time. The word is often used to refer to organisms of a particular kind, such as the plant community on a lawn. Community

Ecosystems and communities contain populations of species. A population is made up of all the members of a species living together in the same place at the same time. An example would be all the ash trees in a wood. Population

Finally each population is made up of many individuals. The genetic and physiological adaptations of an individual organism to its environment is an important aspect of ecology. Individual

Organisms in Ecosystems Habitat – the place where an organism lives out its life Niche – the role and position a species has in its environment – how it meets its needs for food and shelter, how it survives and how it reproduces.

Niche Several species may share a habitat, but the food, shelter, and other resources of that habitat are used in different ways. These differences lead to reduced competition. It is an advantage for a species to occupy a niche different from those of other species.

Food Web

Food Webs Divided into levels known as trophic levels (feeding levels) Composed of: Producers Make their own food (autotrophs) Consumers Must consume food (heterotroph) Decomposers Breaks down waste (dentritivore)

Producers

Consumers

Decomposers

Energy Flow FOOD CHAIN heterotroph Secondary consumer Photosynthesis Primary consumer Autotroph producer 20

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FOOD WEB 22

Energy Pyramid 23

Energy Exchange Energy is not transmitted evenly from our food Usually only 10% of the lower trophic level makes it to the next level (most is used by the organism)

Complex Food Webs Relationships between organisms are greatly intertwined Many organisms are dependent on others for survival