Ch 8 evolution Flashcards
Microevolution
changes in one gene pool of a population over generations
macroevolution
speciation, formation of new species.
can populations change or evolve?
yes
can individuals change or evolve?
no
six areas of study that provide evidence of evolution
fossil record, comparative anatomy, comparative biochemistry, comparative embryology, molecular biology, and biogeography.
fossil record
reveals the existence of species that have become extinct or have evolved into other species.
___% of all organisms that ever lived on earth are now extinct
99
earth is ____ years old
4.6 billion
how is the age of the earth determined
through radioactive dating and half life
_____ were the oldest fossils and earths first organisms
prokaryotic cells
transistional fossils
link older extinct fossils to modern species
comparative anatomy
organisms that have similar anatomical structures are related to each other and have a common ancestor
homologous structures
function of common anatomical structure differs, but has the same interior bone structure. Ex: wing of bat, lateral fin of whale, and human arm
homologous structures are an example of _____ evolution
divergent. we diverged from a common ancestor millions of years ago
analogous structures
same function of not same underlying structure. Ex: bat’s wing and fly’s wing. reflects adaptation to a similar environment.
homologous and analogous structures are evidence of a common origin/ancenstry
no. analogous structures do not provide this evidence
analogous structures are evidence of _____ evolution
convergent.
vestigial structures
evidence that anatomy of animals have evolved. structures that are not used by the body anymore like the appendix, which shows human ancestors had a very different diet.
comparative biology
org’s that have common ancestor will have common biochemical pathways.
comparative embryology
closely related org’s go through similar stages in embryonic development.
molecular biology
since all aerobic org’s have cells that carry out respiration and require ETC’s, they also cojntain necessary protein, cytochrome c. comparison of amino acid sequences of cytochrome c show differences in evolution.
biogeography
theory of continental drift. Pangaea 250 million years ago. study of locations of fossils prove this.
Lamarcks theories
relied on ideas of inheritance of acquired characteristics and use/disuse. individual organisms change in response to environment. Giraffes stretch necks to reach tall trees and pass that on to child.
essence of darwin’s natural selection theory
pop’s tended to grow exponentially to overpopulate and exceed resources (Malthus). Overpop causes competition. There is variation in species as to who survives more easily. best fits survive.
difference between darwin and lamarck
lamarck thought individuals change according to environment and pass on those changes to offspring. Darwin though populations changed based on traits of the best fit org’s.
antibiotics mutated bacteria which then became drug resistant?
no. drugs killed off all the susceptible bacteria, leaving the ones that were resistant to antibiotics. these then reproduced a new generation of drug resistant bacteria.
Stabilizing selection
eliminates the numbers of extremes and favors the more common intermediate forms. weeds out mutants
disruptive selection
aka diversifying. increases the numbers of extreme types in a population at the expense of intermediates
directional selection
peppered moths, environmental changes,
a single point mutation can introduce a new ____ into a population
allele
genetic drift
change in gene pool due to chance EX: bootleneck and founder effect
bottleneck effect
natural disasters the reduce size of a pop nonselectively. loss in genetic variation. pop is smaller and not representative in old one.
founder effect
small population breaks off from original to colonize a new area. rare alleles may be overrepresented
gene flow
movement of alleles into or out of population
hardy weinberg equilibrium
describes stable, nonevolving population where allele frequency does not change
conditions for hardy weinberg
very large population, must be isolated, no mutations, random mating, no natural selection
hardy weinberg equations
p + q = 1
p^2 + 2pq + q^2
species
population whose members have the potential to interbreed in nature and produce viable offspring
anything that fragments a poplation and isolates small groups of individuals may foster a new species
true
horses and donkeys interbreed in nature, they produce a mule which is infertile. are horse and donkey same species?
no
geographic isolation
species are separated by like a lake, mountains, canyons, or glacier.
polyploidy causing isolation?
polyploid organisms cannot breed with others that are not polyploidy
habitat isolation
two organisms are in the same habitat but rarely encounter
behavorial isolation
two animals become isolated ffrom each other because of some change in behavior by one member. fireflies not blinking
temporal isolation
refers to time. some plants sexually mature eariler and flower in winter, whiile others flower in summer.
reproductive isolation
closely related species cant mate because of anatomical incompatability
divergent evolution
population becomes isolated and exposed to new selective pressures. evolves into a new species. evident through homologous structures
convergent evolution
two unrelated species occupy same area, and subjected to similar selective pressures and show similar adaptations. evident by analogous structures
parallel evolution
describes two related species that have made similar evolutionary adaptations after their divergence from common ancestor
coevolution
mutual evolutionary set of adaptations of two interacting species like pollinator-plant relationships
adapttive radiation
emergence of numerous species from a single common ancestor introduced into a new environment. variations of finches beaks on galapagos islands
gradualism
theory that organisms descend from a common ancestor gradually over a long period of time, in a linear or branching fashion. big changes occur by a number of small ones
punctuated equilibrium
becuase of fossil records showing lack or transition, scientists abandoned gradualism for this theory, which states that new species appear suddenly after long periods of no change.
spontaneous generation
theory that living things emerge from nonliving or inanimate objects. disproved with meat and maggot experiment
describe ancient earth’s atmosphere
CH4 (methane), NH3 (ammonia), H2O (vapor), and N2 but no free oxygen. intense haet, lightning, and UV radiation which produced first cell.
heterotroph hypothesis
states first cells on earth (3.5 billion years ago) were anaerobic heterotrophic prokaryotes who simply absorbed surrounding organic molecules
characteristics that enabled animals to move to land
lungs, skin, limbs, internal fertilization mechanisms, and shells for eggs
characteristics that enabled plants to move to land
roots, supporting cells, vascular tissue, cuticle, seeds
mammals appeared on earth about ____ years ago
210 million
humans evolved from apes
no. humans and apes both arose from a common ancestor 10 million years ago.
summary of evolution
it is not always slow (bacteria can take months), does not occur at same rate in every org, does not have to make org’s more complex, occurs in pops, and directed by changes in the enviro.
