AP Bio Unit 8

Population

all the members of one species living and occupying the same niche in an organism

Fitness

measured by an organisms ability to survive and pass on their genes to their offspring

Carrying Capacity

• the total number of organisms in a population that the ecosystem has the resources to support

• determined by limiting factors

Density Dependent Limiting Factors

• become more restricting as the population size increases

• Ex: competition for resources, territorial nature of animals, disease, predation, etc.

Density Independent Factors

• affect the population randomly and do not depend on the size of the population

• EX: natural disaster, climate change, human impact on the ecosystem

Ecosystem Ecology

• study of the interactions between biological communities, including those with the abiotic factors and environmental conditions

• primarily focused on the flow of energy and matter through the environment

Food Chain

• represents a single pathway by which energy, matter and mass flows through an ecosystem

• simpler than what really happens in nature because most organisms are eaten by more than one species.

Food Web

• represents multiple pathways through which energy, matter, and mass flow through an ecosystem

• more accurate representation of which organism consume (or are consumed) by other species

Ecological Pyramid

• energy is passed up a food chain or web from lower to higher trophic levels

• only 10% of the energy is passed onto the next level

  • the remaining 90% of energy is lost as heat

Endotherm

• uses thermal energy generated by metabolism to maintain homeostatic body temperature

• temp will not drastically change with the ambient, environmental temp

Ectotherm

• lack efficient internal mechanisms for maintaining body temperature, though they may regulate their temperature behaviorally by moving into the sun or shade, or by aggregating with other individuals

• temp will change with the ambient, environmental temp

Keystone Species

• those that when removed from the food web/chain will cause a disproportionate and drastic change to the community structure that can lead to ecosystem collapse

Invasive Species

• any species that are introduced to an ecological area in which they are not native

• no natural predators in the ecosystem and thus outcompete the endemic species for resources

Endemic Species

• species that are natural to the area in which they live

Primary Succession

• succession that starts from bare rock and includes the colonization of a new area by a pioneer species

• pioneer species are responsible for making soil from the rock and introducing nutrients into the ecosystem

• result in formation of a stable climax community with high biodiversity

Secondary Succession

• succession that occurs after a climax community is disrupted

• does not start from bare rock

• requires less time to reach the climax community because soil and nutrients are present at the beginning

• result in formation of a stable climax community with high biodiversity

Ecological Community

• comprised of all the populations/species that live in an ecological area together and the niches they occupy

Competition

• characterized by competition for food between members of the same population or members of separate populations

• species that outcompete the other will survive better and pass on their traits, and are more likely to occupy a biological niche

• -/- interaction

Symbiotic Interactions

• long term biological interaction between members of different species/populations

  • predation (+ / -)

  • parasitism (+ / -)

  • mutualism (+/+)

  • commensalism (+/0)

Predation

• predators hunt and kill their prey in order to get energy and nutrients

• herbivores eat plants to obtain nutrients and energy

• (+ / -)

Parasitism

• one organism exploits the other for food and nutrients

• parasites benefit, host is harmed but not usually killed

• (+ / -)

Mutualism

• both species cooperate and gain and advantage from the relationships

• generally some lag time between prey and predator population growth

• (+/+)

Commensalism

• one organism being benefited by the relationship, and the other being completely unaffected (neither harmed nor helped)

• huge doubt as to whether or not commensalism actually exists in nature

• (+/0)