Unit 1 Test Flashcards
Homologous structures
structures in different species that are similar because of common ancestry
Under what condition will evolution NOT occur?
no genetic variation in the population
An organism’s fitness is measured by…?
its contribution to gene pool in the next generation
The biological species concept relies on disruption of….
Gene flow
Which species concept is difficult to apply to bacteria?
Biological species concept
Gene flow
the transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes
Genetic drift
a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next; most apparent in small populations; can cause harmful alleles to become fixed
Biological species concept
Definition of a species as a group of populations who members have the potential to interbreed in nature and produce viable offspring but do not produce viable offspring with members of other groups (species)
Ecological species concept
Definition of a species in terms of ecological niche; the sum of how members of a species interact with the nonliving and living parts of their environment
Morphological species concept
Definition of a species in terms of body shape and other structural features
Habitat isolation
Two species that occupy different habitats within the same area rarely, if at all, encounter each other because of obvious physical barriers
Temporal isolation
Species that breed during different times of the day, seasons, or years
Mechanical isolation
Mating is attempted, but morphological differences prevent its successful completion
Gametic isolation
Sperm of one species may not be able to fertilize the eggs of another
Behavioral isolation
Courtship rituals that attract mat and other behaviors unique to species are effective reproductive barriers, even between closely related species
Reduced hybrid viability
The genes of different parent species may interact in ways that impair the hybrid’s development or survival in its environment
Reduced hybrid fertility
If the chromosomes of the two parent species differ in number or structure, meiosis in the hybrids may fail to produce normal gametes
Hybrid breakdown
Even if the hybrid is viable and fertile, when they mate with another hybrid or one of the parent species, offspring of the next generation could be feeble or sterile
The largest unit in which gene flow can occur is…
A species
What is the order of events in allopatric speciation?
Genetic isolation –> drift –> divergence
What are the two types of extinction?
- Normal Background Extinction (“wedge”)
- Mass Extinction (“wheel”)
What is the “wedge” concept?
It’s when a new species either migrates or a new subspecies is created where at least two species already exist. With them “wedging” themselves into the new environment, one of the existing species will get pushed out or go extinct.
What is the “wheel” concept?
Like the show “Wheel of Fortune,” random, win or lose; a random species will be picked to go extinct; no matter how evolved a species is, they have no better chance of surviving than any other species.
Red Queen Hypothesis
As a species, you must keep evolving and maintaining your fitness to not go extinct.
Hardy Weinberg Equilibrium
In a population that’s not evolving, allele and genotype frequencies will remain constant from generation to generation
- p^2, q^2, 2pq
Law of Constant Extinction
The chance of going extinct in each time period does not change (Red Queen Hypothesis); log graph