Populations and Ecosystems Ecosystem includes all of the

Populations and Ecosystems

Ecosystem- includes all of the living things (plants, animals and organisms) in a given area, interacting with each other, and also with their non-living environments (weather, earth, sun, soil, climate, atmosphere). Ecology- the branch of biology dealing with the relations and interactions between organisms and their environment Biodiversity – the degree of variation of life. Variety of organisms present in different ecosystems.

Plants and animals need air, water, light (plants only), space, food and shelter… these things can be found in their environment. ● Population - all the individuals of a given species in a specific area or region at a certain time. ● Community - refers to all the populations in a specific area or region at a certain time. ● Environment – the surroundings or conditions in which an organism operates. ● Habitat – the natural surroundings or environment in which an organism lives

Biotic and abiotic factors make up an ecosystem… ● Biotic Factor – are all the living organisms within an ecosystem ● Abiotic Factor – are all of the non-living things in an ecosystem (ex: p. H, sunlight, turbidity, available nutrients, wind, etc. )

What is a niche? ● Niche - the status of an organism within its environment and community (affecting its survival as a species). It includes: ● The role a species has in its environment ● Its interactions with the biotic and abiotic factors of its environment

Coexistence and Competition ● Competition – occurs when a resource that is essential to growth and reproduction occurs in short supply. It is an interaction that has a mutually negative effect on the participants. ● Coexistence – occurs when populations of several species that utilize the same limiting resources manage to persist within the same area.

Population Density ● It is a measure of the number of organisms that make up a population in a defined area. ● What is its significance? ● Ecosystems function best when they have the correct number of organisms making up a population to utilize the resources available. ● Ideal number of a population = carrying capacity ● Population density = Population / Total land area

Limiting Factors ● Environmental factors that limit population sizes in a particular ecosystem. ● Examples: ● ● ● Food/nutrients Temperature Water Natural Resources Predation

Density Dependent Factors ● Any factor limiting the size of a population whose effect is dependent on the number of individuals in the population. ● Ex: Disease having a greater effect in limiting the growth of a large population, since overcrowding facilitates its spread.

Density Independent Factors ● Any factor limiting the size of a population whose effect is not dependent on the number of individuals in the population. ● Ex: Earthquake, impacts all members of a population regardless of whether the population is large or small.

8. L. 3. 2 Summarize the relationship among producers, consumers and decomposers, including the positive and negative consequences of such interactions including: Coexistence and cooperation Competition Parasitism Mutualism ● Three categorizes of the food chain: ● Producers ● Consumers ● Decomposers They are dependent on each other!!!

Producers ● Producers get their food and energy from the sun. ● Plants ● They make their food through a process called photosynthesis

Consumers ● Consumers need to eat their food to get energy ● Animals ● Three Types: ● Carnivores ● Herbivores ● Omnivores What type are humans?

Consumer: Carnivores ● Only eat meat (other animals)

Consumer: Herbivores ● Herbivores only eat plants

Consumer: Omnivores ● Omnivores eat both meat (animals) and plants

Decomposer ● Decomposers eat dead things and turn them back into dirt, or soil. ● Ex: Mushrooms, worms, bugs