Ecology

Ecology is the study of the interactions among organisms and their environment

What is the Biosphere? The portion of the earth in which all living things exist Only about 20Km of total diameter of earth From ocean floor to about 8Km above earths surface

Two types of factors in Biosphere Biotic: all things living –Examples? Abiotic: all things non-living –Examples?

Many subcategories Population: all individuals of a certain species within a certain area Community: all the populations of different species within an area

Many subcategories Ecosystem: includes a community and its physical environment –Includes both biotic and abiotic

Individuals have a habitat and a niche Habitat: where an individual organism lives; its home – where is yours? Niche: the role that organism plays in its ecosystem –What is yours?

Relationships between organisms Competition: if two individuals occupy the same niche they will compete –Limited resources like? –Only one will win

Relationships between organisms Symbiosis: two organisms living in close association –Three types: mutualism, commensalism and parasitism

Relationships between organisms Mutualism: both species benefit Example? Why?

Commensalism: one benefits; the other is neither hurt nor helped Relationships between organisms

Parasitism: one species benefits at the other’s expense Relationships between organisms

All organisms require Energy As one organism eats another energy moves through ecosystem Forms food chain Many food chains make food web

Food Chain

Food Web

Mother Nature Recycles All essential inorganic nutrients cycle between biotic and abiotic parts of ecosystem - Water - Oxygen - Carbon - Phosphorus - Nitrogen

Water Cycle

Organisms give off water Water evaporates into atmosphere Water condenses in cloud Falls back to earth in rain/snow Taken back in by Organisms

Carbon cycle

Nitrogen Cycle

Phosphorous Cycle

Oxygen Cycle

Energy Pyramid

Producers/Autotrophs: make food from sunlight or other inorganic molecules – examples: plants, algae and bacteria

Energy Pyramid Primary consumers: eat producers –Herbivores –Examples: rabbits, plankton

Energy Pyramid Secondary or High order consumers: eat primary consumers carnivores –Larger animals –Top consumers are not eaten by anyone

Where do they go then ? Decomposers: bacteria; break down dead organisms and return nutrients (nitrogen) back to the soil for producers to use

Biomes Large groups of ecosystems all with a similar climate Distributed across earth by large shifting blocks of land called – tectonic plates

Shifting Land Sea Floor Spreading

As land shifts so does sun exposure, temperature and rainfall Explains the different climates in different biomes

Succession the changes an ecosystem goes through over time –A kind of “evolution” (simple  complex!)

Primary Succession Begins with rocks Pioneer species: Moss and Lichens

Primary Succession Primary succession begins in barren areas, such as the bare rock exposed by a retreating glacier. First inhabitants are PIONEER SPECIES –lichens or mosses –grown on bare rock –convert the rock into soil that can support simple plants such as grasses. GRASSES : further modify the soil, which is then colonized by other types of plants. –Each successive stage modifies the habitat by altering the amount of shade and soil composition. CLIMAX COMMUNITY: Stable final stage that can endure for hundreds of years..

Secondary Succession Occurs after a disturbance

Secondary Succession After a major disturbance, –fire or flood. –Farmland that has been plowed Secondary succession is similar to primary succession –one important difference: primary succession always begins on a barren surface, –secondary succession begins in an area that already has soil.

–Climax community is the goal, but is rarely reached –Disturbances can set the ecosystem back Fires, logging, flood,etc.

Climax community

Limits to an Ecosystem

Thomas Malthus Plants and animals produce far more offspring than can survive, Man too is capable of overproducing if left unchecked. Unless family size was regulated, man's misery of famine would become globally epidemic and eventually consume Man.

Carrying Capacity An ecosystem has only enough resources to support a certain number of organisms –This number is the ecosystem’s Carrying Capacity – Non-renewable resources – Renewable resources

CC controlled by competition immigration emigration catastrophic events seasonal fluctuations in food, water (available resources) hiding places, and nesting sites (shelter and “family homes Population Densities

Stable or Not?

STABLE! There will always be “fluctuations” around the average

What happens as we approach the carrying capacity?

Competition Survival of the fittest –Numbers cannot go higher because there are limited resources. –If an invasive species is present, could result in extinction or severe lowering in the numbers of other species due to lack of predators for the invasive species!