Ecosystems

Ecosystems Biology 12E Investigate and explain the interactions in an ecosystem including food chains, food webs, and trophic pyramids. Ch

What is an Ecosystem? All living organisms & nonliving environment in a certain geographical location. – Has biotic and abiotic factors. Examples: pond, forest, grasslands, ocean

Terms to Know Ecology – study of the relationships of organisms to their physical environment and to each another. Habitat – place where a certain population of species lives. Community – the many different species that live together in a habitat. Biodiversity – the number of species living together in an ecosystem.

Biotic Factors -organisms in a habitat. Abiotic Factors – physical, nonliving things in habitat

Abiotic factors affect living organisms in an ecosystem. – How would these abiotic factors affect the living in an ecosystem? Fire Hurricanes Wind Frost Tornado

Biotic factors affect the abiotic factors in an ecosystem. – How would these biotic factors affect the abiotic factors in an ecosystem? Animal on side of road Algae and fungi on rocks

Niche Role of a species in an ecosystem. All the physical, chemical, and biological conditions a species needs to live & reproduce. – Keystone species – species that has large effect on other organisms.

Producers Organisms that use the sun to get energy and make their food through a process called photosynthesis. Also called autotrophs.

Types of Consumers (Heterotrophs) Herbivores - animals that only eat plants. Carnivores - animals that eat other animals (meat).

Omnivores - eat both plants and animals. Detritivores – organisms that break down dead organisms. Also called decomposers.

Energy flow in Ecosystems Everything organisms do in an ecosystem requires energy. All energy in an ecosystem starts with the sun. Energy transferred from one organism to another. – Some energy used by animal and some is lost.

Trophic Levels Energy pyramid-shows how energy moves. All organisms assigned category of producers or consumers. – Producers at bottom of the pyramid as they are eaten first. Amount of energy is lost, or decreases, as more organisms eat each other. 10% rule – only 10% of original energy is left to feed next level. Multiple by 10% to figure out how much is left over

Food Chain: A food chain shows one path of how energy moves through an ecosystem (who-eats-who).

Food Web: A food web is made up of many different food chains. A food web shows many paths of how energy moves through an ecosystem (who-eats-who).

Food chainFood web (just 1 path of energy) (all possible energy paths)

Limitations Food and water supply – Can increase or decrease population. Population size – Can have an affect on food and water supply. Carrying capacity - maximum population of a particular species that a given habitat can support over time.

Toxins in food chains- While energy decreases as it moves up the food chain, toxins increase in potency. This is called biological magnification or biomagnification Ex: DDT & Bald Eagles

Definition The process where plants & animals in a particular area are replaced by other more complex species over time. Succession

2 types Primary vs. Secondary Primary begins with a lifeless area where there is no soil (ex. bare rock). Soil formation begins with lichens or moss.

Secondary begins in an area where the natural community has been disturbed, removed, or destroyed, but soil or bottom sediments remain.

Pioneer Communities Beginning communities – Ex. Lichens and moss (simple plants).

Climax Communities The area dominated by a few, long-lived plant species. More complex

Stages Land – rock  lichen  small shrubs  large shrubs  small trees  large trees

Water – bare bottom  small/few underwater vegetation  temporary pond and prairie  forest and swamp

Activity Draw a food web. Should have at least one decomposer, 2 producers, 2 primary consumers, 2 secondary and 2 tertiary consumers. Must label each. Color, draw arrows correctly, and be neat.