Ecology Levels of Organization in Ecology Ecologists study

Ecology

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.

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

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.

Biosphere • The volume of the earth’s surface where organisms can be found. • It extends from the depths of the ocean (11 km below sea level) to at least the highest plant communities (6. 2 km)

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.

Ecosystem • 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 selfsufficient unit in balance with their environment.

Community • 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.

Population • 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.

Individual • 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.

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 heterotroph Primary consumer Autotroph producer

FOOD WEB

Energy Pyramid

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