Principles of Ecology O’Connor/Chapter 2

Ecology The study of interactions that take place between organisms and their environments. Biosphere ~ the portion of Earth that supports living things. Extends from high in the atmosphere to the bottom of the oceans.

Living vs. Nonliving Abiotic Factors Nonliving parts parts of an organism’s environment. Ex. Air currents, temp., moisture, light, and soil. Biotic Factors All living organisms that inhabit an environment. Ex. Animals & plants.

Levels of Organisms To understand interactions of the biotic and abiotic parts of the world, ecologists have organized the living world into levels – The organism itself, populations, communities & ecosystems.

Populations A group of organisms, all of the same species, which interbreed and live in the same area at the same time. Map of populations by countrycountry

Biological Communities Interacting populations in a certain area at a certain time.

Ecosystems Interacting populations in a biological community and the community’s abiotic factors.

Types of Ecosystems Terrestrial Forrest Old farm field Meadow Yard Garden plot empty lot Compost heap Volcano site Rotting log Aquatic Freshwater –Pond –Lake –Stream –Estuary Marine (salt H2O) -ocean -estuary -aquarium

Other Ecosystems Human Body - ex. Skin Buildings - ex. Basement Food - moldy food

Habitat A place where an organism lives out its life.

Niche A role or position a species has in its environment- how it meets its specific needs for food & shelter, how & where it survives, and where it reproduces in its environment.

Symbiosis Relationship where there is a close and permanent association between organisms of different species. Three kinds: Mutualism Commensalism parasitism

Mutualism Both species benefit + + Ex. Ants & acacia trees- ants feed off it & protect it from damaging predators

Commensalism + o One species benefits and the other species is neither harmed nor benefited.

Parasitism + - When one species benefits at the expense of another species. Flea bites on human

How organisms Obtain Energy The producers – autotrophs The consumers – heterotrophs The decomposers

Energy Flow Through the Ecosystem

A food Chain - Web A model that scientists use to show how matter & energy move through an ecosystem. In a chain nutrients & energy move from autotrophs to heterotrophs & eventually to decomposers.

The arrow points to the mouth the eats it.

Which of these is an omnivore?

Levels of heterotrophs First –order (primary consumers)ex. Herbivores like deer, turtles & fish. Obtain food by eating photosynthetic organisms. Second-order (secondary consumers) Carnivores like owls. They eat first order heterotrphs like mice. Third-order -Carnivores that feed on second order heterotrophs. Ex. Bears, lions, humans

Biomass Foundation species (also known as primary producers) harvest an energy source such as sunlight and turn it into biomass. Primary production is generation of biomass through photosynthesis.

Biomass Production The highest producers of biomass are tropical rain forests, 2000 g/m²/yr of biomass swamps and marshes, 2500 g/m²/yr of biomass algal beds and reefs, 2000 g/m²/yr of biomass Lowest producers are deserts and frozen areas (less than 200 g/m²/yr of biomass)

Trophic Levels

Cycles in nature The water cycle The carbon cycle The nitrogen cycle The phosphorus cycle The materials of life, such as carbon & nitrogen, are used and reused as they cycle through the ecosystem.

Water Cycle

Carbon Cycle

Nitrogen Cycle

Phosphorus Cycle