7a slides Flashcards
what is the endosymbiont theory
-prokaryote engulfed other prokaryotes
-gave rise to animal/fungi lineage and plant/algae lineage
why do prokaryotes and eukaryotes regulate gene expression
in response to cellular and environmental cues
in multicellular eukaryotes what does gene expression regulate
development and is responsible for differentiation of cell types
what is phenotype product of
inherited genotype and many environmental infleunces
genetic variation
differences in composition of genes between individuals
phenotype
observable physical and physiological traits of an orgabism which are determined by its genetic makeup
genotype
genetic makeup or set of alleles of an organism
what makes evolution possible
genetic variation
why is genetic vriation within a population a prerequisite for evolution
within a population genetic idfferences among indiduals provde the raw material on which natural selection and other mechanismsi can act. Without such differences, traits could not change oer time- and hence the population could not evolve
what are two ways new genes and alleles can arise
mutation or gene diplication
how cna sexual reproduction add to the genetic variation among individuals
by recombiing existing alleles
which mutations are passed to offspring
mutations occurring in gametes
what can extend genome length
duplication of genes de to errors in meiosis
true or false
duplicated genes can take on new functions by further mutation
true
in organisms that reproduce sexually how does most genetic variation result
recombination of alleles
three mechanisms that can shiffle exisiting alleles into new combinations through three mechanisms
crossing over
-independent assortment
-random fertilization
average mutation rate in plants and animals is what
1 mutation in every 100,000 genes per generation
are mutation rates fast in eukaryotes or prokaryotes
eukaryotes
what allows prokaryotes to allow mutations to accumulate rapidle
short generation tmes
evolution
process by which species accumulate differences from their ancestors as they adapt to different environments over time
microevoltuion
evoltion at its finest level, is the change in allele frequencesies in a population over generations
macroevolution
evolutionry change above the species level
-origin of a new group of organisms through a series of speciation events
-impact of mass extinctons on the diversity of life and its subsequent recovery
population
group of individuals of the same species that live in the same area and interreed, producing fertile offspring
what is the only thing that evolves
populations
what is evolution at its finest level
chnage in allele frequencesies in a population over genrations
three main mechnsism tat cause allele frequency change are
-natural selection
-genetic drift
-gene flow
what is the only thing taht causes adaptive evolution
natural selection
adaptive evolution
a process in which traits that enhance surivial or reproduction tend to increase in frequency over time, resulting in a better match between organisms and their environment
natural selection
process in whihc individuals that have certain ingerited traits tend to survive and reproduce at higher artes than other indivuals because of those triats
genetic drift
process in which change events cause unpredictable fluntuations in allele frequencies from one genration to the next
gene flow
transfer of alleles from one population to another, resulting from movemnet of fertile individuals or their gametes
