Evolution
How do you study evolutionary process?
you focus on changes that occjt within populationa
what is microevolution?
the change in percentages or frequencies of alleles within populations
what are the five processes of microevolution
mutation, gene flow, non-random mating, genetic drift, natural selection
what are mutations
the more generic variation, the greater the chance of a selective advantage, and the greager genetic diversity
what is the source for generic variation?
mutations
what is gene flow?
the net movement of alleles from one population to another as a reault of the migration of individuals
what is non-random mating?
mating among individals on the basis of a particular phenotype or due to inbreeding
what is inbreeding?
closely related individuals breed. pure-breeding results in health problems.
what is genertic drift?
the change in frequencies of alleles due to random events in a small breddinf population. (the failure of a few individuals to reproduce intesifies the effects of generic drift)
what is the founder effect?
formed by a few individuals that carrh some alleles. The gene pool is reduced.
What is the bottleneck effect?
A populatkon ia reduced by disease, starvation, or natural catastrophe. gene pool loses lts diversity because of the loss of alleles.
what are the three types of natural selection?
stabilizing
directional
disruptive
what is natural selection?
gene traits that are selected for by the environment will end up surviving
what is stabilizing selection?
favours an intermediate phenotype and not extreme phenotypes.
what is directional selection?
favours the phenotypes at one extreme. (ie: girrafes with long necks)
what is disruptive selection?
favojrs two extremes.
what is sexual selection?
competiton between males through combag or vishal displags.
define sexual dismorphism
where males and females look verh different
define gene pool
all the alleles of all genes in a population
what is lactose tolerant?
thwu havw rhe switched tirned on and have the lactase gene
What are the 5 sources of evidence for evolution?
Fossil, Biogeography, Anatomy, Embryology, DNA
What is fossil evidence?
fossils that are younger are more similiar to present species (closer to surface)
what is biogeography evidence?
the study of the past and present geographical distribution of organisms. That species evolved in one location and spread
What is anatomy evidence?
homologous structures are thosr whi have similiar structure but has different functions or those who have similar functions bjt not a commkn structure
what is evidence from embryology?
study of pre-birth stages of development. related species share common embryological stages.
evidence from DNA?
soecies whi have similiar DNA share a common ancestor
what is selective pressure?
how certain traits can be favored and the enviornment exerts a pressure on those whodont have a favoured trait
what is natural selection?
organisms better adapted to their environment tend to survive and produce more offspring
what is artifical selection?
humans affect the pooulstion and alter to their liking
what is genetic diversity?
the range of different genetic traits within a species
how does genetic variation help?
genetic variation helps species survive due to the various traits they have
what is speciation?
formation of new species from existing species.
what is pre-sygotic barriers?
impede mating between species or prevenr fertilization if different species mate
what are the 5 pre-zygotic barriers?
behavioural, temporal, habitat, mechanical, gametic
what is post-zygotic?
two different species prodjce a zygote and prevent hybrids from being fertile
what are the three barriers of post-zygotic mechanisms?
hybrid inviability, hybrid breakdown, hybrid sterlitity
whatis divergent evolution?
a pattern of evolution in which species that were once similar become less and less alike
what is convergent evolution?
a pattern of evolution in which similar traits arise in diff species due to adaptikns to enviornment
what is sympatric speciation?
populations that live in the same habitat diverge and become reproductively isolated
what is allopatric speciation?
populations are seperated by a geographical barrier and diverge genetically
what are the two types of speciation?
sympatric, allopatric
adaptive radiation
the process in which species are rwpudly diversifyint from the ancestor species
what is gradualism?
evolutionary change as slow and steady
what famous islands did darwin study?
galapos
what is darwins famous evolution book?
On the origin of species
what is fitness?
the ability to survive and reproduce
whatjs survival of the fittest
being able to survive in yojr enviornment. the most fit will survive
what is descent with modification and how do fossils show it?
that species change and give life to new species. fossils show the evolution of soecies overtime. older fossils are less similar to modern day
what are fossils
the remains of plangs and animals in ehicj is buried
what are adaptations
the ability for a soecies ti adapt ti their surroundings
what is homologous structures and example?
similar features that have a common ancestor. Ex: wings of bat and flipper of whale
what are vestigial organs
organs that no lomger have any function ex: appendix
what are two examples of adaptstions?
mimicry (looks like a predator) and the english peppered moth
how does isolation relate to speciation
isolation allows for seperstion in the species group leading to the creation of new species
what are analogous structure
a strucure that has similar function but not from the same ancestor
what is gradualism?
the model for the slow changes of evolution overtime
what is extinction?
the dissaoearance of a species
what is micro snd mscro evolution
micro evolution is small changes over short periods while macro is large changes iver long periods
what is antibiotic resistance
when a bacteria is able to mutate and overcome the medication lesding to antibiotic resistance. happens if too overuse the drug
what is lactose intolerant
when your bodh doesnt produce lactase and cant break fown the protein in lactose
what is george cuviers theory
that species were extinct by catastroohic events like flooding
what is charles darwin theory?
believed in natural selection. biological evolution by natural selection. believed in gradualism as well. apecies adapt and change to their environment and some are favored ti survive
what is jean-baptiste theory?
that aquired traits are inheritable. its called lamarkism
what is thomas nalthus theory?
malthiusm. a theory that populations are greatee than accesible recourses
what is charles kyell theory?
the formation of Earth's crust took place through countless small changes occurring over vast periods of time, all according to known natural laws. His "uniformitarian"
whag are rhe three patterns of selection?
disruptive, directionsl, stabilizing