Ecology Unit

What is ecology? Ecology- the scientific study of interactions between organisms and their environments, focusing on energy transfer It is a science of relationships

What do you mean by environment? The environment is made up of two factors: Biotic factors- all living organisms inhabiting the Earth Abiotic factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, air currents)

Organism Population Community Biosphere Ecosystem

OrganismOrganism- any unicellular or multicellular form exhibiting all of the characteristics of life, an individual. The lowest level of organization

PopulationPopulation-a group of organisms of one species living in the same place at the same time that interbreed and compete with each other for resources (ex. food, mates, shelter)

CommunityCommunity- several interacting populations that inhabit a common environment and are interdependent on one another

EcosystemEcosystem- populations in a community and the abiotic factors with which they interact (ex. marine, terrestrial)

BiosphereBiosphere- life supporting portions of Earth composed of air, land, fresh water, and salt water The highest level of organization

“The ecological niche of an organism depends not only on where it lives but also on what it does. By analogy, it may be said that the habitat is the organism's ‘address’, and the niche is its ‘profession’, biologically speaking.” Odum - Fundamentals of Ecology

Habitat vs. Niche Niche - the role a species plays in a community, i.e. decomposer, predator, prey, scavenger, parasite Habitat- the place in which an organism lives out its life

Niche An organism’s niche is determined by it’s ability to get resources from the environment, avoid limiting factors, and avoid competition with similar and neighboring species Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment

Examples of limiting factors- Availability of water Availability of food Temperature Amount of living space Competition Predation Limiting Factors

Feeding Relationships There are 3 main types of feeding relationships 1. Producer- Consumer 2. Predator- Prey 3. Parasite- Host

Feeding Relationships Producer- all autotrophs (plants) that trap energy from the sun through the process of photosynthesis Base of most food chains

Feeding Relationships Consumer- all heterotrophs that “eat” other organisms as food for energy  Herbivores  Carnivores  Omnivores  Decomposers

Feeding Relationships CONSUMER Herbivores –Eat plants Primary consumers Tend to be prey animals

Feeding Relationships CONSUMER Carnivores - eat meat Secondary, Tertiary and Quaternary consumers Predators – hunt prey animals for food

Feeding Relationships CONSUMER Scavengers -feed on carrion and other dead animals Feed from many different levels of the ecosystem depending on what animal has died

Feeding Relationships Consumer- Omnivores -eat both plants and animals

Feeding Relationships CONSUMER Decomposers Breakdown the complex compounds of dead and decaying plants and animals into simpler molecules that can be recycled into the soil and reabsorbed by the roots of plants

Trophic Levels Each link in a food chain is known as a trophic level When an organism eats food, it is consuming both energy and matter (biomass) Trophic levels represent a feeding step in the transfer of energy and matter in an ecosystem

Total Biomass Biomass- the amount of organic (living) matter comprising a group of organisms in a habitat, i.e. literally, the total weight of all individuals of a particular type of organism As you move up a food chain, both available energy and biomass decrease Energy is transferred through a food chain but is diminished with each transfer

Trophic Levels Producers- Autotrophs Primary consumers- Herbivores Secondary consumers- small carnivores Tertiary consumers- top carnivores ENERGYTRANSFERENERGYTRANSFER

Trophic Levels Food chain- simple model that shows how matter and energy move through an ecosystem

Trophic Levels Food web- shows all possible feeding relationships in a community at each trophic level Represents a network of interconnected food chains

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