Ecology Part 2 Flashcards
Attempts to show key growth characteristics of real populations, these characteristics include: immigration, emigration, birth rate, death rate
Population model
A group or organisms of the same species that live together in one place at one time
Population
The movement of individuals into a population
Immigration
The movement of individuals out of a population
Emigration
This occurs when numbers increase by a certain factor in each successive time period
Exponential growth
A factor that restrains the growth of a population
Ex: food, predators
Limiting factor
Begins with a minimum number of individuals and reaches a maximum depending on carrying capacity
Logistic growth
The number of individuals the environment can support over a long period of time
Carrying capacity
Reduce population regardless of the population’s size
Ex: floods, forest fires, global warming
Density-independent factors
Factors that affect populations due to their size, and always involve resource availability
Ex: number of nesting sites, food resources
Density-dependent factors
Species are currently disappearing faster than at any time since the last mass extinction (65 mya). It is estimated that about 1/5th of the species in the world may disappear this century
6th mass extinction
Narrows the gene pool and makes them less able to adapt to changing environmental conditions (mating with relatives)
Inbreeding
The act of one organisms killing another for food
Ex: camouflage, mimicry
Predation
The act of an organism living off another organism. The host is usually larger than the parasite and is harmed but not killed
Ex: ticks, fleas
Parasitism
The eating of plants, often without killing the plants.
Locust trees-thorns
Milkweeds-bad tasting chemicals
Herbivory
A relationship between two species that live in close association with each other. Two forms are mutualism and commensalism
Symbiosis
A relationship between two species in which both species benefit
Mutualism
A relationship between two organisms in which one organism benefits and the other is unaffected
Commensalism
The organism’s role in the community
Niche
The entire range of conditions where an organism or species could survive
Fundamental niche
The actual niche that a species occupies in a community
Realized niche
The exclusion of one species by another due to competition
Competitive exclusion
When some species avoid competition for resources with similar species by dividing the resources
Resource partitioning
Are critical to an ecosystem and affect the survival of many species in the community
Keystone species
