Ecology

Ecology… The scientific study of interactions between organisms and their environment

Levels of Organization Biosphere = thin zone that contains ALL life of Earth

2. Ecosystem = a self supporting group of communities and their physical environment Biotic factors: all the LIVING organisms that inhabit an environment ‘bio-’ = life Abiotic factors: all the NONLIVING part of the environment ‘a-’ = without; ‘a’ ‘bio’tic = without life

rock, flower, sun, popcorn, grass, soil, water, animal, tree, carcass Living (biotic) Nonliving (abiotic) Dead

Living (biotic) Nonliving (abiotic) Dead Flower Grass Animal Tree

Living (biotic) Nonliving (abiotic) Dead Flower Grass Animal Tree Rock Sun Soil Water

Living (biotic) Nonliving (abiotic) Dead Flower Grass Animal Tree Rock Sun Soil Water Popcorn Carcass

Levels of organization (continued) 3. Community = all the living organisms in a specific area (Ex. Pond, forest)

4. Population: = all the individuals of the same species living in the same area at the same time 5. Organism = any living thing

BiosphereEcosystemCommunity PopulationOrganism Overview: (largest  smallest) BiosphereEcosystemCommunity PopulationOrganism How to remember order? Big Elephants Consume Peanuts Often

Habitat = the place an organism lives Niche = the role (job) an organism has in it’s community

Species = a group of like organisms that can reproduce AND have fertile offspring

NOT a species… Horse + Donkey = Mule A mule is not fertile. In order to make more mules, there must be more (horse + donkey)

Lion + tiger = liger Babies are sterile therefore NOT a species

Symbiotic Relationships Symbiosis = the relationship in which there is a close and permanent association between organisms of different species 3 types:

1. Mutualism Relationship in which both organisms benefit Organism 1 = = Benefit Organism 2 = = Benefit

Example of mutualism Ants and the acacia tree

2. Commensalism relationship in which one species benefits and the other is neither harmed nor benefited Organism 1 = = benefit Organism 2 = = no harm, no benefits

Example of commensalism Spanish moss growing on trees

3. Parasitism Relationship in which one species benefits and the other is harmed Organism 1 = = benefit Organism 2 = = harmed

Example of parasitism Tapeworms

Overview Relationship Organism 1 Organism 2 Mutualism Commensalism Benefit Commensalism No benefit, not harmed Parasitism Harmed

Ecological Niches 1. Producers: Also called autotrophs ‘auto-’ = self ‘troph’ = feeding These are organisms that make their own food Ex. green plants

2. Consumers: Also called heterotrophs ‘hetero-’ = different Organisms that can NOT make their own food Three categories: A. herbivores: eat plants (primary consumer)

B. carnivores: eat other consumers; eat meat (secondary/tertiary consumers) C. omnivores: eat both plants and animals (tertiary consumers)

3. Decomposers: break down organic matter and return it to the environment

Food Chains The flow of energy and organic molecules from organism to organism Energy for this system originates from the SUN Food chains ALWAYS begin with a PRODUCER

Food Webs Complex relationships formed by interconnecting and overlapping food chains

Food Pyramids 1. Pyramid of numbers The higher up the food chain the lower the number of organisms

2. Pyramid of energy 90% of the energy is lost to the environment at each level of the food chain 3. Pyramid of biomass The amount of biomass decreases at each level of the food chain

Community Distribution Limiting factor: any biotic or abiotic factor that restricts an organism’s ability to survive Ex. Food supply, water supply, living space Tolerance: the ability to withstand fluctuations in biotic and abiotic environmental factors

SUCCESSION the orderly, natural change in communities over time Primary succession: development of living communities from BARE ROCK NO soil present Ex. Rock lichens moss ferns shrubs trees mature trees

Pioneer organism: the first organism to inhabit a community (ex Pioneer organism: the first organism to inhabit a community (ex. lichens) Climax community: a stable, mature community that undergoes little or no succession Primary succession takes a relatively long time to reach this point

Secondary succession: the development of living communities that takes place when a community is disrupted by natural disasters or human impact Soil IS present Takes less time to reach climax community Ex. Abandoned farms, fires…

Population Growth Exponential growth: when the number of organisms increases by an ever-increasing rate. 248163264128256etc J-shaped curve

Carrying capacity: the number of organisms of a population a particular environment can support over an indefinite period of time S-shaped curve

Factors that affect the size of populations 1. Birth rate 2. Death rate 3. Growth rate = birth rate – death rate 4. Immigration: movement INTO an area 5. Emigration: movement OUT of an area