Ecology

Organism Species Group of similar organisms that can breed and produce offspring. Group of similar organisms that can breed and produce offspring.

Population Population A population is all the members of a given species in a given area. Example - All the turtles in a lake.

Habitat The physical location where plants and animals live is called a habitat. A habitat is filled with different species, each of which depends on the habitat’s resources to meet its needs.

Niche Each of the organisms that lives in a habitat has a role to play in its habitat, a role which is referred to as its niche.

Community Community – All a given area constitute a community. Community – All the species that live and interact in a given area constitute a community.

Ecosystem All the living things along with their environment form the Ecosystem.

Biome R Regions of Earth that are similar in climate and have similar types of plants are called biomes.

Biosphere The part of the earth where life exists including land, water, air, and atmosphere

Levels of the environment: Biome Ecosystem Community Population Organism

Organism A single individual animal, plant, fungus, or other living thing.

Population A group of organisms of the same species that live in the same area.

Community All the living components of the ecosystem form a community. Different plants, animals, and other organisms interact with each other.

Ecosystem An ecosystem consists of the living things and their environment.

Biome The climate and types of plants that are found in similar places around the world.

Levels of Organization Ecologist study organisms ranging from the various levels of organization: Ecologist study organisms ranging from the various levels of organization: –Species –Population –Community –Ecosystem –Biome –Biosphere

Interactions Among Organisms - Organisms interact in different ways: Predator and Prey Predator and Prey Competition Competition Cooperation Cooperation Symbiosis - Symbiosis -MutualismCommensalismParasitism

Predator and Prey: The predator is an animal that eats another. The prey is an animal that is eaten by a predator.

Competition: Competition is the Competition is the struggle between individuals or different populations for a limited resource.

Cooperation Cooperation Cooperation is an interaction in which organisms work in a way that benefits them all.

Symbiosis Symbiosis The relationship between individuals of two different species who live together in a close relationship is called symbiosis. A symbiotic relationship may affect the partners in different ways : Mutualism - Both species benefit from the relationship. Commensalism - One species benefits while the other is not affected. Parasitism - One species benefits while the other is harmed.

Mutualism Mutualism is an interaction between two species that benefits both. Example -The relationship between a flower and a bee. The bees get food in the form of nectar, and the flowers get pollen from other flowers, which they need to make seeds.

Mutualism -

Mutualism The oxpecker gets food (ticks and insects) and a safe haven from the rhinoceros, and the rhinoceros has parasites (ticks) removed.

Commensalism Commensalis m Commensalis m is a relationship between two species in which one species benefits while the other is not affected.

Parasitism Parasitism Parasitism is a relationship between two species in which one species benefits while the species it depends on, its host, is harmed.

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Ecosystems are always changing - Populations change over time because of Growth or Decline – Birth Rate Predator-Prey Interactions Lack of Nutrients/Abiotic Factors Pollution

Limiting Factors - Limiting Factors - Any factor or condition that limits the growth of a population in an ecosystem is called a limiting factor. These could be biotic factors or abiotic factors.

Limiting Factors

Carrying Capacity - When a population reaches a state where it can no longer grow, the population has reached it’s carrying capacity, or the maximum number of individuals that an ecosystem can support. An ecosystem’s carrying capacity is different for each population.

Succession - Succession is the gradual change in an ecosystem in which one biological community is replaced by another. Over time the grasses of open farmland are slowly replaced by small plants and shrubs, then trees. This change from field to forest is an example of succession.

Succession

Primary Succession - Very few places on Earth are without some form of life. Even when a lava flow covers an area or a glacier retreats and leaves behind an empty and barren environment, plants will move into the area and bring it back to life. These are examples of primary succession, the establishment of a new biological community.

Primary Succession at Glacier Bay, Alaska A climax community is the stable community at the final stage of succession.

Primary Succession

Pioneer Species - The first plants that move into an empty and barren area and bring it back to life are called Pioneer Species. As the pioneers grow, they gradually weaken the rock surface. The rock breaks down and weathers over time. Decaying plant matter adds nutrients, forming soil. A variety of small plants and shrubs take root. These plants, in turn, support insects, birds, and small rodents. Eventually there is enough soil to support coniferous trees. Forests grow, providing a stable habitat for larger animals.

Secondary Succession - Secondary succession takes place after a major disturbance to the biological community in a stable ecosystem. A community can be disturbed by a natural event, like fire or flood, or by human activity. Despite the disturbance, the soil remains there. The damage, is surface damage only. Below the surface, seeds and plant roots survive. Gradually grasses and small shrubs grow up among the decaying remains of the original plants. Birds, insects, and rodents return. Alder trees take root and put nutrients into the soil. Over time, a variety of trees and plants grow, providing food for numerous animals.

Secondary Succession

Ecological succession is the set of changes in community composition that occur over time in a new or disturbed community. Ecological Succession Succession after the Yellowstone fires. Succession at Mt. St. Helens.

The final stable plant community may reach a point of stability that can last for hundreds or thousands of years.

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