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Explain why paleontology and the use of fossils support the idea that livingthings change over time.
This support the idea thatliving things change over time by having remains or traces of organisms from the past. Fossils, in particular strata (new sediment cover older ones andcompress them into superimposed layers of rock), provide glimpse of theorganisms that populated earth at the time the layer formed.
1. use and disuse- idea that body parts ofthe body that are used become stronger and larger and those that don’tdeteriorate.
2. Inheritance of acquiredcharacteristics- organism could pass these modifications to its offspring.
Histheory is rejected b/c today we understand genetics, experiments show thattraits acquired by use during individuals life are not inherited.
Variation: members of a population oftenvary greatly in their traits. Inheritance-traits are inherited by offspring from parents.
Selection: species produce more offspring than cansurvive, many do not survive. Time- overtime inherited traits give offspring a better chance tosurvive and reproduce. Adaption-accumulation of favorable traits in the population over generations(individuals do not evolve, population does)
biogeography: geographic distribution of species, plants& animals drifted apart, adapted to new environments, landmasses haveevolved.
ex. Theory- Pangaea was one large mass 250 mill yrs ago but broke apart200 mill yrs ago.
direct observation of evolutionary change: observed livingthings evolve in the last 200 yrs.
Fossil show past organisms differed form living organismsthat many species become extinct and that species have evolved over longperiods of time.
Ex. trace the evolution of new groups, as in the origin of whales from land mammals
Describe the differenttypes of homology comparisons usedto support evolutionary theory.
Anatomical homology- having shared or alike features orresemblance that can be seen. ex. forelimbs of all mammals (humans, cats, whales,and bats) show same arrangement of bones from the shoulder to the tips ofdigits.
Molecular homology- similarities among organisms at the molecularlevel, all forms of life use the same genetic language of DNA and RNA= likely that allspecies descended from common ancestors.
Describe how biogeography supports evolutionarytheory.
It is the geographic distributionof species and it has been influenced by continental drift, the slow movementsof the Earth’s continents.
Explain examples of direct observations of evolutionary changementioned in class (HIV, staph bacteria) and the selective processes thatoccurred to influence each.
HIV: virus thatcauses AIDS. Drug 3TC inhibits HIV enzyme reverse transcriptase, preventsviruses from replicating. But, HIV evolves….use of drugs selects for resistantviruses. Over time, drug-resistant viruses become major ones in the populationof HIV.
Staph bacteria: causesskin infections. Penicillin - an antibiotic, discovered in the 1930s
Penicillin-resistantStaph appeared in 1945. This evolution took place by VISTA.
Explain whynatural selection can act only on heritabletraits.
It is a process inwhich individuals with beneficial characteristics produce more offspring thanothers because of the inherited characteristics that contribute to an organism’ssurvival and reproduction in a specific environment. Also, because these arethe traits that directly participate in evolution
why is beingheterozygous sometimes an advantage.
Change in DNA sequence, change proteins, change cells, and change organism. Makes mistakescoping DNA. Point mutations, insertions, deletions-tiny changes (new alleles)
occurs when the environmentfavors individuals on both extremes of a phenotypic range.
A few individuals become isolated from a larger population.
vasodilation is the increase in the internal diameter of blood vessels that is caused by relaxation of smooth muscle.
vasoconstriction reduces blood flow and heat transfer, bloodvessels decrease in diameter
After detecting invadingpathogens, a phagocytic cell engulfs them trapping them in a vacuole, whichfuses w/ lysosome and kills it by two ways. 1) gases from lysosome poisonengulfed pathogen 2) lysosome & other enzymes degrade components ofpathogens.
found beneath mucosalsurfaces, they discharge destructive enzymes.
how inflammation affects blood vessels of the infected tissue
Explain the role ofthe MHC molecules in antigenpresentation.
the display of the antigenfragment in an exposed groove of the MHC proteins. If cell displaying an antigen fragment encounters a T cellw/ right specify, antigen receptors on the t cell can bind to both antigenfragment and the MHC molecule.
short-lived cells that takeeffect immediately against the antigen and any pathogens producing thatantigen. Produced during b/t cell multiple cell division
the antibody secretingeffector cell of humoral immunity. They arise from antigen-stimulated b-cells.Produced during activation of b cells
Plasma cells help combatinfection by stopping expressing a membrane-bound antigen receptor and beginproducing/secreting antibodies. Each of these cells secrete 2,000 antibodiesevery second.
Explain the differencebetween active and passive immunity, and name someexamples of each.
Active immunity- long lasing immunity conferred by the action of B cells and T cellsand the resulting B and T memory cells specific for a pathogen.
Passive immunity- short termimmunity conferred by the transfer of antibodies
Example- occurs duringbreast-feeding
Kidneys produce urine. Concentrates filtrateinto about 1.5 L of urine. Two main regions: renal cortex (outer) and renalmedulla (inner). Filtrate is made and concentrated in nephrons into urine.Urine drains from nephron into renal pelvis to ureter.
Descending limb of the loop of henle
Ascending limb of the loop of henle
Know the composition of filtrate, how filtrate is formed, andwhat molecules are or are not normally found in the filtrate (and why).
carries filtration viamedulla to the renal pelvis, transport epithelium of the nephron and collectingduct process filteration= urine. Epithelium task is to reabsorb solutes andwater. When filtrate passes epithelium of collecting duct hormonal control ofpermeability and transport determines extent urine becomes concentrated.
Proliferationphase- estradiol and progesterone secreted by corpus leutum = continue develop.+ maintenance of uterine lining (enlargement of arteries, growth of endometrialglands= secrete nutrient fluid that can sustain early embryo b4 it implants).Drop in ovarian hormone= arteries in endometrium constrict= release blood.During menstruation, new group of ovarian follicles will grow .
Common neurotransmitter, found in CNS and PNS.
Important role - released by motor neurons.
Targets muscle cells.
Binds to an acetylcholine receptor, causes ions to rush into muscle cell.
rods and conesare the photoreceptors in the retina. They contain light-absorbing moleculesbonded to a protein (opsin). Rods are more light sensitive and enable nightvision, whereas cones distinguish colors. Rods contain the pigment rhodopsinwhich
changes shapewhen absorbing light
Greaterreproductive success of heterozygous individuals compared with homozygotes;tends to preserve variation in gene pool
Ex: HbS/HbA –protects against malaria
the process by which one species splits into two or more species
changes over time in allele frequencies in a population
the broad pattern of evolution above the species level
a group of populationswhose members have the potential to interbreed in nature and produce viable,fertile offspring-but do not produce viable, fertible offspring with members ofother such groups
(before the zygote) block fertilization fromoccurring. Such barriers typically act in one of three ways:by impeding membersof different speicies from attempting to mate, by preventing an attemptedmating from being completed successfully, or by hindering fertilization ifmating is completed successfully.
Describe Postzygotic barriers
(after the zygote) may contribute toreproductive isolation after the hybrid zygote is formed. For example:developmental errors may reduce survival amount hybrid embroyos. Cause them tobe infertile
twospecies that occupy different habitats within the same area may encounter eachother rarely, if at all, even though they are not isolated by obvious physicalbarriers such as mountain ranges. EX: two species of garter snakes in the samegenus, occur in the same geographic areas but one lives in water while theother lives in a land.
species that breed during different times f the day, differentseasons, or different years can not mix their gametes ex: one mates in winterwhile another mates in the spring
courtship rituals that attract mates andother behaviors unique to a species are effective reproductive barriers, evenbetween closely related species. Such behavioral rituals enable mate recognition-a way to identify potential mates of the same species ex: fish likes certainpatterns on their mates
mating is attempted but morphologicaldifferent prevent it’s successful completion. Ex: snails mating and they spiralin different directions.The snails gential opening are nnot aligned so matingcannot be completed.
sperm of one species may not be able tofertilize the eggs of another species. For instance, sperm may not be able tosurvive in reproductive tract of females of the other species, or biochemicalmechanisms may prevent the sperm from penetrating the membrane surrounding theother species eggs
even if hybrids are vigorous, they maybe sterile. If the chromosomes of the two parent species differ in number ofstructure, meiosis in the hybrids may fail to produce normal gametes. Sinceinfertile hybrid cannot produce offspring when they mate with either parent species, genes cannot flow freely betweenspecies ex: horse+donkey=mule
Explainhow speciation is occurring in North American hawthorn maggot flies (Rhagoletispomonella).
There was a small percentage that was into the apple tree. Theystarted to reproduce there and meet their mates and offspring. From there ittook about 200 years. Provides a post zygotic barrier to reproduction. Limitinggene flow. These two populations are classified as sub species instead ofseparate species. (sympatric speciations)
Distinguishbetween allopatric speciation and sympatric speciation,and describe mechanisms that may lead to each.
allopatric speciation- the formation of new species in populationsthat are geographically isolated from one another.(severly restrict geneflow)(natural selection under different environment changes)
Sympatric speciation- the formation of new species in populationsthat live in the same geographic area. (natural selecton-food source orhabitat)
Punctuated Equilibrium: Evolutionary Change Can Occur Rapidly.
This was proposed to explain the gaps in thefossil record. The punctuated equilibrium hypothesis states change only happensunder certain conditions, and it happens rapidly.
Discussthe factors that allow for speciation to occur gradually.
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