69 terms

Bio Exam 4

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Concepts that are fundamental to the theory of evolution.
charcteristics of living things change with time; the change is directed by natural selection
evolution
the change in the genetic makeup of a population over time.
genetic recombination
is the sum total of all the gene mixing that occurs during sexual reproduction
acquired characteristics
gained during lifetime -- are not passed on (learned behaviors)
Natural Selection
states that individuals with genes that make them better adapted to their surroundings are more likely to have higher survival rates and produce more offspring
differential reproduction
organisms with genes that make them more "fit" will reprodice more offspring = therefore the favorable genes will become more common in population
gene frequency
is a measure of how often a given gene turns up in the gametes of a population
Hardy-Weinberg Law
when the 4 conditions are met thus resulting stabilty in gene frequency
4 assumptions to constant gene frequency...
population is large enough so that change alone or accidental deaths will not change gene frequencies; mutations must not occur; there can be no immigration or emigration; reproduction must be totally random
1) population is large enough so taht change alone will not occur gene frequency
population has to be infinitely large to rule out chance, avoid genetic drift; result in indeterminate evolution
genetic drift
chance can cause evolutionary change in small population
indeterminate evolution
since genetic drift is not influenced by the relative adaptiveness of he change in allele frequency
2) mutations must not occur
never met; mutations are always occuring; not usually a major factor in changing gene frequency; don't determine the direction of evolutionary chagne
3) there can be no immigration or emigration
gene flow; sometimes not met in nature
gene flow
some gene migration between populations. increases genetic variability in population
4) reproduction must be totally random
more than mating process; includes many factors that contribute... selection of mate, physical efficency, feritily, surival
selection pressures
factors that act to disturb the HArdy-Weiberg equilibrium
range
the geographic distribution of a species
Species can move to a new geographic area by...
traveling under its own power; be carried by storms and winds; attached to other organisms or human-transported objects
colony
if the new area is suitable the species will establish here and its range will expand
exotic species
species introduced because of human activities
pests
exotic species -- there are no natural enemies or competitors in their new home.
geographic isolation
when a portion of the gene pool become seperated from the rest of the gene pool by some geographic change
geographic barriers
mountains, rivers, deserts, cause geographic isolation
selecting agents
enviroment differences; causes differences to arise between 2 gene pools.
subspecies
over a long period of time the genetic differences result in regional populations; different phenotype and genotype but still produce fertile offspring
specification
is the process of generating new species; occurs when gene flow between 2 isolated populations does not occur even after the geographic barriers are removed
Steps of specification
geographic isolation of part of poulation; differences in selecting agents; genetic differences so great
allopatric population
different ranges
sympatric population
same range
reproductive isolating mechanisms or genetic isolating mechanism
mechanisms that prevent interspecies mating
ecogeographic isolation
occurs when 2 populations become so specialized for different enviromental conditions -- can;t survive where other occurs
habitat isolation
occurs when 2 synpatric populations occupy different habitats within their common range
seasonal isolation
occurs when 2 closley related sympatric species breed during different season
behavioral isolation
occurs when behavioral cues are associated with successful courtship and mating
mechanical isolation
occurs when structural differences betwen 2 closely related species prevents matings (usually differences in spape of genitalia)
gametic isolation
occurs when 2 different species are able to mate but egg and sperm will not for a zygote
developmental isolation
occurs when mating and fertilization between 2 species are successful but the embryo does not develop properly
hybrid inviability
occurs when a hybrid resulting from interbreeding dies before reproducing or is so weak or malformed that it can't reproduce
hybrid sterillity
occurs when a hybrid is vigourous but sterile
selective hybrid elimination
occurs when a hybrid is capable of reproducing but they and their offspring are less fit and soon eliminated form the population
polypoidy
plants forming new species, is when the number of chromosomes present is increased
Gene Buffon
thought that animals might change over time. but dod not come up with a mechanism that would cause evolution
Lamarck
suggested a process by which evolution could occur; suggested taht acquired chacteristics could be passed down to offspring
Darwin and Wallace theory for natural selection
all organisms produce more offspring than can survive; no 2 organisms are exactly alike; among organisms there is a constant struggle for survival; individuals with favoriable characteristics are more likely to survive and produce; favorable characteristics become more common in teh species and unfavorable characteristics are lost.
evolutionary trees
trace evolutionary changes over time; with limited evidence; creationists
divergent evolution
the basic pattern of evolution; specification events cause branches in the evolution of a group of organisms.
adaptive radiation
characterized by a rapid increase in the number of kinds of closely related species
2 situations in adaptive radiation
an organism invades a previously unexploited enviroment; an organism evolves a new set of characteristcs that allows it to dispalce organisms taht previously occupied an eniroment niche
convergent evolution
occurs when organisms of widely different backgrounds develop similar characteristics
microevolution
is the type described by Darwin... slow, progressive change
macroevolution
whole groups of characteristcs change at same time; many new species appear and many old species become extict
punctuated equilibrium
pattern of slow change for millions of years followed by rapid cahnge
spontaneous generation
living organisms from nonliving material
biogenesis
lving organisms only from other living organisms
Francisco Redi
italian doctor who designed experiement to disprove spontaneous generation. used 2 jars with maggots
Louis Pasteur
french chemists, convinced msot people that spontaneous generation did not occur; used sugar in beakers
Alexander Oparin and JBS Haldane
russioan biochemists and british biologists; independtly proposed the idea of spontaneous generation in a new form.
reducing atmosphere
no oxygen
Stanley Miller
conducted experiment to see if organic material can be formed from inorganic material. able to synthesis amino acids and sugars
A portion of the early ocean was seperated from the rest and began to evaporate
as evaporation occurs the simple organic molecules become more concentrated; the water disappear macromolecules could have form by dehydration synthesis
simple organic molecules could have been concentrated by freezing
as the water was tied up due to freezing the simple organic molecules would have become more and more concentrated; as the water became frozen and unavailable, macromolecules could have formed by dehydration synthesis
clay particles could have attracted and concentrated the simepl organic compounds
dyhydration reaction to form macromolecules.
prebionts
nonliving structures led to the first living cells
coacervate
consists of organic macromolecules surrounded by a shell of water molecules.
protenoid mecrospheres
are droplets that form when hot aqeous mixtures of polypeptides are cooled
anaerobic
don't need oxygen to survive
oxidizing atmosphere
contains oxygen in atmosphere
basic building blocks
carbs, lipids, nucleic acids