BIO 101, Ch 40, Interactions Within & Among Species

Interspecific Interaction

an interaction between individuals of different species that affect the per capita birth and/or death rate (or equivalently the fitness) of at least some of the individuals involved

Fitness

how successful an organism is at surviving and having offspring that carry its genes.

Interspecific Competition

(-/-) a mutually detrimental interaction between individuals of two different species that cause both to suffer reduced fitness fitness because they both require the same resource

Limiting Resource

A resource that constrains the fitness of individuals at a given time and place because it is in short supply relative to demand.

such resources include food, light, space, pollinator's attention

Consumption Interactions

(+/-) organisms obtain nutrition by consuming or harming other living organisms or are they themselves consumed or harmed

Predation

one individual (predator) gains fitness by killing and consuming the other individual (prey), which loses fitness as a consequence

Herbivory

individual (herbivore) consumes all or part of a plant

Parasitism

individual (parasite) consumes part of the host individual but usually does not kill it

Mutualism

(+/+) interaction that benefits both species

Commensalism

(+/0) influences only one individual who benefits, while the other individual is unaffected

Amensalism

(-/0) interaction that harms one individual but does not affect the other

Intraspecific Competition

a mutually detrimental interaction between individuals of the same species that causes both to suffer reduced fitness

causes a decrease in population growth

math equation used to show intraspecific competition

Growth = Maximum growth − competition from A − competition from B

density dependent

things that affect a population more when there are MORE organisms.

rarity advantage

When being rare or less common gives an organism a better chance of surviving or reproducing.

Resource Partitioning

When different species use different resources so they don't compete for exactly the same things.

Trophic

Referring to feeding

Primary Producers

photosynthetic or chemosynthetic organisms that synthesize complex organic molecules from simple inorganic ones, energy enters the community through them

also called autotrophs: photoautotrophs or chemoautotrophs

Heterotroph

An organism that gets energy and nutrients by eating other organisms instead of making its own food.

Primary Consumers

heterotrophs that consume primary producers (aka herbivores)

Secondary Consumers

those that eat herbivores (aka carnivores)

Tertiary Consumers

eat secondary consumers

Omnivores

feed on both plants and animals, feed from multiple trophic levels

Decomposers

feed on waste products or dead bodies of organisms

Trophic Levels

The feeding positions in a food chain or web, represents energy flow

Food Web

a diagrammatic representation of which organisms consume which organisms in an ecological community (diagram of trophic relationships)

The more complex, the more stable

Trophic Cascade

When one species increases or decreases, it can affect other species that eat it or are eaten by it.

Invasive Species

a species that increases in abundance and spreads wildly, often to the detriment of other species, when it is introduced to a new location

Altruism

An organism helps another organism, but it costs them something.(±/- )

Niche

range of conditions a species can tolerate and range of resources a species can use (role of an organism in its habitat)

Food Chain

A series of events in which one organism eats another and obtains energy; a section of a food web

Foundation Species

large contribution towards creating and maintaining habitats that support other species, usually found in higher numbers

ex: aspen trees

Intraspecific Interactions

between members of the same species

Keystone Species

A species that may not be the most common, but is very important to keeping the ecosystem balanced. If you remove it, the ecosystem can fall apart or change a lot.

Character Displacement

different traits selected for difference resource partitioning

ex: finch beak size for seed size

Niche

the role and position a species has in its environment, including all interactions with biotic and abiotic factors.

herbaviors

omnivores

organisms that eat both plants and animals

decomposers

organisms that break down dead organic material, recycling nutrients back into the ecosystem.

herbivores

organisms that primarily consume plants.

carnivores

An animal that eats other animals for food