General Ecology Chapter 3 Flashcards
Balancing selection
type of natural selection that maintains genetic diversity in a population
Balanced polymorphism
where 2 or more alleles or morphs are maintained in a population
Disruptive selection
favors the survival of individuals at both extremes of a range rather than the intermediate
Biological Species Concept
defined species as groups of populations that can actually or potentially exchange genes with one another and that are reproductively isolated from other such groups
Phylogenetic species concept
advocates that members of a single species are identified by a unique combination of characters
Evolutionary species concept
species is distinct from other lineages if it has its own evolutionary tendencies and historical fate
Allopatric speciation
involves spatial separation of populations by a geographical barrier
Sympatric speciation
occurs when members of a species that initially occupied the same habitat within the same range diverge into two or more different species
Continental drift
the slow movement of the Earth’s surface plates
Convergent evolution
leads to emergence in each realm of herbivores and predators that have evolved from different taxonomic ancestors
Red Queen hypothesis
describes evolutionary history of life as a continual race with no winners, only losers
Gradualism
new species evolve continuously over time
Punctuated equilibrium
the tempo of evolution is more sporadic
The birth weights of human babies generally lie in the range of 3-4 kg (6-9 lbs). Mothers cannot deliver much bigger babies, and small babies tend to have increased mortality. This is an example of:
Stabilizing selection
The biological species concept is based on species’:
Reproductive isolation
In what geological period did most phyla on Earth arise?
Cambrian
The original supercontinental landmass present 280 million years ago was called:
Pangaea
The gradual movement of the Earth’s landmasses across the surface of the world is known as:
Continental drift
The biogeograhic realm that incorporates South America is known as:
Neotropical
Most recorded extinctions have been caused by:
Introduced species and Habitat destruction
Elimination of native species by introduced species has been commonly caused by:
Predation and Parasitism and disease
As a percentage of prescribed species, which taxa is currently threatened most with extinction?
Amphibians
Which of the following characteristics increase a species sensitivity to extinction
Increased rarity
