Test One Flashcards
Population undergoing natural selection
- Individuals of a given age will differ predictably from the individuals which do not survive that age.
- The offspring of a given generation will differ predictably from their parents
Adaptive radiation: examples would be?
Two animals that are genetically related, but occupy different purposes.:
Ex: honeycreepers and Tasmanian wolf.
Bottleneck
Species do not very much. They pass through a funnel.
Three models of natural selection
Stabilizing, disruptive, and directional
Stabilizing selection
Outcome that is in favor of average values of the trait and to disfavor extreme traits
Disruptive selection
Disruptive selection in which two different extreme phenotypes are simultaneously favored, but their average is disfavored. This creates two very different phenotypes that dominate the environment
Directional selection
Favors a phenotype value either above or below the average and causes the population to shift toward the favored value over time.
Evolution
Any change in the genetic constitution of a population of organisms. Anything from small to large.
Evolutionary force
Any factor in the external environment or in the bodies of the organisms themselves that induces shifts in the frequency of genes within a population
Evolution to Darwin was
Descent with modification
Theory
A set if statements or principles devised to explain a group of facts or phenomena, eapecially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena
Inheritance
If a trait cannot be inherited, it cannot be passed on
Balenced polymorphism
A special type of genetic polymorphism I which two or more alleles persist in a population over many generations as a result of natural selection. Heterozygous traits maintain the recessive gene when dominant
Cline
Measurable gradual change over a geographic region in the average of some phenotype or genotype character such as color size and gene frequency.
Jean-Baptiste Lamarck
Soft Lamarckism
Lamarckism
Born 1 aug 1744-18 dec 1829
Came up with the theory of inheritance of acquired characteristics
Ex of NS malarial flies
Fly into huts Bite someone Land on wall to digest meal Walls then sprayed with DDT flies quit landing in wall Hit ad run mosquitoes
NS EXAMPLE Culex pipe a
Insect developed an antidote for insecticide which is digested by esterases
Carry 250 different alleles for resistance
Gradualism
Small differences are the raw material from which the different major forms of life evolved.
Phenotypic gradualism
New traits, even those that are strikingly different from ancestral ones, are produced in a series of small, incremental steps
Punctuate equilibrium
Phenotypic evolution is. Concentrated in relatively brief events of branching speciation, followed by much longer intervals of evolutionary stasis
Sexual selection
Used to denote the selection of traits that are advantageous for obtaining mates but may be harmful for survival
Fitness
The total number of an individuals direct and indirect fitness; includes the genes contributed directly to offspring and those contributed indirectly by kin selection
Adaptation
The condition of showing fitness for a particular environment as applied to the characteristics of a structure, function, physiology or the entire organism and the process by which fitness is acquired by an individual.
Genetic drift
The evolution of the genetic constitution of a population by chance processes alone.
Example of genetic drift
There is 50:50 chance that two Herero Aa will give a Aa or a homo allele AA/aa.
Founder effect
An extreme example of genetic drift: a small population colonizing a new area: bucket of marbles. Pronghorn
Hardy-Weinberg equilibrium assumptions
There is random genetic drift Random mating Mutations do not occur No migration No natural selection
Types of speciation
Allopatric, sympatric and stasipatric
Allopatric speciation
Lineage independence is achieved while two or more lineages are geographically separated. Eventually becoming two separate species
parapatric speciation
Lineage independence is achieved between geographically distinct lineages which maintain limited inter lineage mating across a contact zone. Form own species
Stasipatric speciation
Lineage independence is achieved by major chromosomal rearrangements which give rise to postmarking isolating mechanisms.
Sympatric speciation
LI is achieved w/o geog. Separation but by shifts in ecology, hosts, time of reproduction, or by hybridization: such as the same species in same environment but eat different types of plants leafs
An evidence of plate tectonics
Similar flightless birds all found on southern continents: rheas, ostrich, emu, cassowaries, elephant birds, moas, kiwis, tinamous
Pangea separated into to two
Laurasia and gondwana
Biogeographic realms
Nearctic- N. America
Neotropical- S. America
Palearctic- Russia and Europe+ small Africa
Ethiopian- most Africa
Oriental-Asia
Australian- Australia
Wallace’s line is between oriental and australian
Niche
Place occupied by a species in its ecosystem, where it eats, what it eats, foraging route.
Adaptive radiation
Term applied to the spread of species of common ancestry into different niches. Fishes African cichlids have minute differences dies to their niches. Also honeycreepers are another example(different beaks for insects or plants