Bis 2B Midterm 2

increased atmospheric concentration facilitated the evolution of larger and more active animals

the advent of recombination and independent assortment of chromosomes during meiosis provided the genetic variation necessary for diversity in body plans

evolution of genes that control the transcription of many other genes enabled animals to develop diverse and complex body plans

the advent of sight enabled animals to forage many different ways leading to different body plans

evolution of predators selected for adaptations in their prey that enabled them to escape predation

occurred 251 Myr ago, extinction of 96% of species

occurred 65 myrs ago, extinction of 76% of species (most famous)

What caused the mass extinctions?

form of mutation-single base pair substitution in DNA

no change in the amino acid translation

results in amino acid substitution on the polypeptide

caused by insertion or deletion of one or more base sequences which results in a series of amino acid substitution during translation

transfer of a segment from one homologous chromosome to the other

Hereditary determinants in the egg and sperms are irreversibly blended

hereditary determinants in the egg and sperm are passed from generation to generation through discrete particles.

an observable physical features

a particular form of a flower (purple)

a particular trait is the only form present when crossed over many generations; Mendel used only such parents

different forms of a gene

when an individual has the same copy of an allele

when an individual has different copies of an allele

when an allele is expressed in a heterozygous individual

when an allele is not expressed in a heterozygous individual

when an individual (with 2 copies of each allele) produced gametes, each contains only one copy

The site on a chromosome occupied by a specific gene

alleles of different genes assort independently of one another during gamete formation

association between genes on the same chromosome such that they do not show independent assortment

when heterozygotes show a phenotype intermediate between those of the two homozygotes

Pattern of inheritance characteristics caused by genes located on the sex chromosome

predation and abiotic disturbances are at an intermediate level in the tropics, allowing more species to coexist

study of the allele frequency distribution and change in a group of interbreeding organisms

characteristics displayed by an organism caused by its genetic constitution, environmental factors, and interactions between genetic and environmental factors

the genetic constitution of an organism at one or more specific loci

the proportion of a population that has a particular genotype

the proportion of all genes in the population present in a particular form

the assumptions of the hardy-weinberg model

a form of nonrandom mating in which individuals are more likely to mate with relatives than with nonrelatives

set of species living in a particular place

probability that a pair of genes are identical by descent

reduction in fitness of inbred organisms caused by increased frequency of deleterious recessive genes

random change in gene frequencies within populations caused by sampling error

when p=1.0, the allele is____
when p=0, the allele is _____

the proportion of the population that are heterozygous

The study of continuously measured traits (such as height or weight) and their mechanics

a phenotypic trait that varies continuously (rather than discretely) for different character states

Quantitative traits are typically ____

The proportion of the phenotypic variance that is made up of genetic variance

Two ways to measure heritability are?

variation in alleles within individuals and populations and between populations

accumulation of mutations that do not affect fitness

crossing over and independent assortment of chromosomes amplifies the number of possible genotypes

maintains genetic diversity when the fitness of rare genotypes in higher than common genotypes

when fitness is higher for heterozygotes than homozygotes

how does gene flow affect the populations?

movement of genotypes from one population to another

a process that occurs when individuals share resources that are in short supply

individuals deplete resources by consuming or using them

aggressive encounters among individuals

competition among individuals of the same species

Competition among individuals of different species

two species cannot coexist if they have the same niches

where a species lives and how it obtains resources

when species differ in the way they utilize their resources

the limit in the degree of overlap that will allow species to coexist

what are the three ways a species may partition their resources

when species differ more where they are together (sympatric) than where they are alone (allopatric)

when an animal eats another organism

when an animal eats another animal

when an animal eats a plant

when an animal eats an organism that it lives on or in

when two or more species affect one another's evolution

an example of coevolution which involves resource partitioning, character displacement

predators select for defensive traits in prey, which selects for traits in predators that weaken the defense of prey

species that are brightly colored to advertise that they are harmful

when two or more species (usually aposematic) resembles one another

when a non harmful species resembles a harmful species

when two or more harmful species resemble one another

the study of multiple species interactions and abiotic factors on the structure and dynamics of community

when predators reduce prey populations and thereby prevent competitive exclusion of prey species, increasing diversity

when abiotic disturbances reduce prey populations and thereby prevent competitive exclusion of prey species, increasing species diversity

4 known hypothesis on why there are more species in the tropics than in other areas on earth (4 total)

species are more specialized in the tropics allowing more species to coexist

temporal change in community composition

this type of succession begins on bare rock or sand (no soil)

this succession begins on soil

this theory states that communities are fundamental units of highly integrated species and succession proceeds towards a predetermined climax

in this theory, communities are collections of non-integrated species with similar physical requirements and succession doesn't proceed towards a predetermined climax

what are the 3 mechanisms of succession