Chapter 4: Evolution, Biological Communities, and Speciec Interactions Flashcards
Acclimation
The ability of an organism to respond immediately to the changing environment.
Adaptation
The aquisition of traites that allow a species to survive in its environment.
Mutation
Changes in the DNA coding sequence that occur by chance.
Habitat
The place or set of environmental condtions in which a particular organism lives
Ecological niche
Describes the functional position of an organism in its envirnment
Resource partitioning
species co-exist in a habitat by utilizing different parts of a single resource
Ex: Swallows eat insects during the day and bats eat insects at night
Speciation
The developement of a new species
Allopatric Speciation
whereby a sub-population becomes
separated from the main population and can no longer
share genes with it.
Sympatric Speciation
Organisms continue to live in the same place but become isolated by some other means
Genetic drift
Chance events that casue genes to be lost from a population through generations of reproduction
Selection pressure
The selsetion pressures on the two populations are differentt if the populations are isolated
Intraspecific competition
competition among members of the same species whihc can be reduced
Interspecific competition
competition between members of different species
Predator-mediated compition
One species may be the top predator in a given location, but its population may be reduced as the number of prey decreases
Coevolution
Over time predator and prey evolve on response to one another
Batesian mimicry
Harmless species mimic the warning coloration of harmful species to gain protection
Mullerian mimicry
Two harmful species evolve to look alike
Symbiosis
2 or more species living intimately together with their fates linked
Mutualism
Both organisms benefit from their association
Commensalism
One species benefits while the other neither benefits nor is harmed
Parasitism
a form of preditation, also sometimes considered a symbiosis because of the dependency of the parasite on its host
Keystone Species
Has a large effect on biological community relative to its abundance
Primary Productivity
Rate of biomass production. Used as an indication of the rate of solar energy conversion to chemical energy
Net Primary Productivity
energy left after respiration
Abundance
Total number of organisms in a community
Diversity
Number of different species, ecological niches, or genetic variation
Ecological structure
pattern of spatial distribution of individuals and populations within a community
clustered/clumped ditribution
for protection, mutual assistance, reproduction, access to resources
uniform distribution
often the result of competition
complexity
number of species at each trophic level and the number of trophic levels in a community
3 kinds of resilience and stability
Constancy, Inertia, and Renewal
Edge Effects
an important aspect of community structure is the boundary between one habitat and adjacent ones
Ecotones
boundaries between adjacent communities
Primary Succession
a community begins to develop on a site previously unoccupied by living organisms
Ex: a lava flow creates a new land area that is colonized. The first colonists are termed pioneer species
Secondary Succession
An existing community is disrupted and a new one subsequently develops at the site
Climax Community
Community that develops last and remains the longest
