Bio test 3 Answers – Flashcards

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population
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individuals of the same species living in the same area smallest biological entity that can evolve
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evolution
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change in the allele frequencies through time due to conditions that violate the hardy-weinberg equilibrium
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hardy-weinberg equilibrium
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no evolution because of a lack of mutations, random mating occurrences, no natural selection, extremely large population size, and no gene flow. The outcome is allele frequencies do not change.
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Mutation
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random effect that causes a change in the DNA sequence of a gene, typically the ultimate source of new alleles, combination with sexual reproduction generates variations among individuals in a population
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gene flow
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genetic exchange between populations, increases genetic diversity within a single population, decreases genetic among multiple populations
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genetic drift
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random changes in allele frequencies that is especially important in small populations, due in part to organisims being discrete entities, can reduce genetic variation within a population
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founder effect
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small group starts a new population, may not be representative of the gene pool of the original population, usually does not contain all of the genetic variation in original population
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population bottleneck
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population drops to a very small size before recovering, survivors of bottleneck may not be representative of entire original population, often lowers the genetic variation in a population ex: prairie chickens in illinois
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natural selection
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non-random effect that is the differences in the reproductive success in genotypes and leads to adaptation in population, reduces genetic variation when there is a heterozygous advantage
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absolute fitness
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number of offspring produced by genotype
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relative fitness
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standardized and the highest it can be is 1 with the other genotypes being some kind of fraction
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high frequency of type O blood in native americans and type A blood in Australians and N america
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due to genetic drift
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decreased frequency of B alleles in Eurasia from east to west
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due to gene flow because invaders brought the allele with them when they invaded and repopulated the area
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high frequency of B alleles in asia and africa
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due to natural selection, smallpox has a sugar similar to that found on A blood and bubonic plague has H molecule like is found on type O blood
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sexual reproduction cost
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offspring only carry half of a parent's allele
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benefit of sexual reproduction
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genetic variation in offspring
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male
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make small usually motile gametes called sperm
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female
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make large more expensive non motile gametes called eggs
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blue headed wrasse
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start off life as a female and if it become the biggest fish it switches into a male
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clown fish
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larger of the pair should be the female, males have same fitness as their female mates size
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grey squirrel
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males that have a larger body size fight for mates while smaller body sized individuals wait for mates
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sexual selection
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trait with survival cost has mating benefits, sex investing more in the offspring should be choosy, males fight for access to survival, females select males with certain traits
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good genes hypothesis
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trait is a handicap such as bright colors or long tail but if the individual can survive it shows evidence of good genes to give to offspring
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good provider hypothesis
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male provides parental care and the trait is evidence of good qaulity and good at providing for the young
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directional selection
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individuals at 1 end of the distributions do very well and individuals on the other end don't do as well
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stabilizing selection
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those that have intermediate phenotype do very well but those at extremes do not do as well
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disruptive selection
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those on the extreme ends of the distribution do better than those that have the intermediate phenotype, tends to increase the genetic variation of a species
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biological species concept
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group of actually or potentially interbreeding populations that produce viable and fertile offspring; key aspect is reproductive isolation
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ecological species concept
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set of organisims exploiting a single niche, key aspect is the resources exploited and the habitat occupied by the members of a species, deals with the area a species lives in
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morphological species concept
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set of species with morphological features in common, deals with looks
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phylogenetic species concept
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defined by its unique genetic history as a tip of a phylogenetic tree, key aspect is that species are defined by their unique derived features and shared ancestry, deals with genetics
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allopatric speciation
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a population forms a new species while geographically isolated from its parent population
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dispersal allopatric speciation
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organisims leave the parent population and move to an area that was previously uninhabited
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vicariance allopatric speciation
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a large population is split in two by some kind of physical force
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physical barrier
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interrupts gene flow
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sympatric speciation
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no geographic barrier to gene flow; polyploidy, habitat specialization, and sexual selection prevents reproduction between individuals from different populations living in the same area
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genetic divergence
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can occur in allopatric or sympatric, accumulation of genetic differences between 2 populations that causes mutation, genetic drift including founder effect, and differential selection
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reproductive isolating mechanisms
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prevents interbreeding to produce viable and fertile hybrid offspring and can be pre or post-zygotic
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reinforcement outcome between populations
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the lineage continues to diverge
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fusion outcome between populations
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if the hybrids are viable the 2 populations come back together
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stability outcome between populations
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the hybrids do really well for themselves
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characteristic of mammals
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milk nucleated red blood cell hair
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FOXP2 gene
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mutation in this gene is primarily responsible for severe language disorder called developmental verbal dyspraxia which is characterized by difficulty and identifying basic speech sounds, understanding sentences, and judging grammar, autosomal dominant; unmutated gene is responsible for the speech abilities of humans and affects the basal ganglia which is important for fine control of the mouth and larynx
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autosomal dominant
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all of the affected people have an affected parent, males and females are equally affected, and cannot skip generations
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autosomal recessive
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males and females are equally affected but can skip generations because the gene can be hidden in the heterozygote
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sex linked recessive (X chromosome)
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males more likely to affected, unaffected daughters of affected males are heterozygous carriers, can skip generations
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if humans evolved from chimps why haven't chimps turned human
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humans did not evolve from chimps rather humans and chimps evolved from a common ape ancestor
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New world monkeys
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found in central and south america, have a prehensile tail for gripping, and the nostrils open towards the side
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old world monkeys
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found in Asia and Africa, no prehensile tail, and nostril open downwards
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hominoids
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apes long arms, short legs and no tails larger brain relative to body size flexible behavior
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human chromosome 2 in humans
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2N= 46
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human chromosome 2 in chimps bonobos gorillas, and orangutan
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2N= 48
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hominoids
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gibbons, orangutans, gorillas, chimps, bonobos, humans, and fossil ancestors
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hominids
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orangutans, gorillas, chimps, bonobos, humans, and fossil ancestors
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hominin
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humans and fossil record ancestors
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bipedalism in humans
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came before larger brains, shift in the foramen magnum, the spine curved to allow for weight to be centered above legs, wider pelvic girdle, angled femur, hallux in line with other phalanges
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sahelanthropus tchadenis
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6-7 MYA, small brain case with a flat face cose to chimps possible human ancestor
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Ardipithecus ramidus
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4.4-5.7 MYA, small brain case, hallux opposable on foot, very large arms and hands, able to walk but can't not run like humans, found in woods
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Australopithecus afarensis
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3-3.9 MYA, small brain case, bipedal walking upright,
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Laetoli footprints
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big toe in line with other toes, beginning of arch, Australopithecus afarensis
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Lucy
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Australopithecus afarensis , 3 year old female that had a similar shoulder blade to human
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A. africacanus
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2.4-2.8 MYA, small brain case, Bipedal- known by the position of the foramen magnum
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A. sebidia
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1.95-1.78 MYA, small braincase
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Paranthropus
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strong jaw muscles, side branch that didn't lead to humans
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Homo habilis
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1.6-1.9 MYA, larger brain case, flatter face, bipedal, first evidence of tool use
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Homo ergaster/ erectus
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0.4-1.8 MYA, larger brain case, flatter face, bipedal, pronounced brow ridge, Turkana boy
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first to leave africa
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Homo erectus
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Homo sapiens
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0.1 MYA-present, larger braincase, flatter face, chin, reduced brow ridge, bipedal
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origin of life
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1. abiotic synthesis of organic molecules 2. abiotic synthesis polymers 3. RNA world- enzymes to catalyze reactions, self replication 4. formation of protobionts with membranes
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Mitochondria and chloroplasts have
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2 internal membranes, circular DNA, some ribosomes
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Cambian explosion
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in 10 million years all major animal body plans evolved, prior animals were all soft bodied and unlikely to fossilize
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new genes new body plan hypothesis
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regulatory genes control development and duplication of these genes allow more complex body plans
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continental drift
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land masses attached to plates that float around the surface of the earth, former position of land masses can explain distribution of species
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mass extinction
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occurs when greater than 60% of the species go extinct in less than a million years, followed continuation of survivors
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end permian mass extinction
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more than 90% of species went extinct, highest rate of extinction, largely due to the formation of pangea
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pangeas effect on the end permian extinction
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less shallow coastal marine habitat, changes in ocean current and chemistry, more interior land causing drier climates, volcanoes, changes in the atmosphere due to gasses released from earth
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K-T mass extinction
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65% of the species went extinct, demise of all the dinosaurs except the birds, due to an asteroid impact that caused tsunamis, fires, earthquakes, global cooling, and acid rain
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2 kingdoms
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1. plantae 2. Animalia
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five kingdoms
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1. plantae 2. animalida 3. fungi 4. protista- single celled eukaryotes 5. monera- prokaryotes
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3 domains
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1. Eukarya 2. archaea 3. bacteria
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monera
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replaced by archaea and bacteria
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challenges of land colonization
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desiccation or drying out air does not support the same as water reproduction
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Hox genes
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regulatory genes in animals that control the body plan of the animal
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arthropods adaptations in colonizing land
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prevent desiccation by developing a chitin skeleton out of water support by exoskeleton and jointed limbs gas exchange by a tracheal system internal fertilization and eggs
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tetrapod limbs
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hox gene expressed along the length of growing limb
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polysyndactyly
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mutation of Hox 13 gene that gives 6 toes
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AER limb bud
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secret fibroblast growth factor and controls proximal - distal axis
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ZPA limb bud
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secretes sonic hedgehog and controls anterior posterior axis
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characteristics of animals
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eukaryotic multicellular heterotrophic no cell walls diplontic life cycle blastula and germ layers
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diplobasts
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have ectoderm and endoderm
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triploblasts
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ectoderm, endoderm, and mesoderm in the middle
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coelomate
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cavity is lined with mesodem
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pseudocoelomate
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cavity only has one side lined with mesoderm
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Acoelomate
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no cavity
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choanoflagellates
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closest relative to animals
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4 shared features of chordates
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notochord dorsal hollow nerve cord post anal tail pharyngeal slits or cleft
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Amphibians adaptation to colonizing land
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mucus coat to prevent drying legs and heavier skeleton for support on land external fertilization and eggs laid in water
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amniotes "snakes, lizards, turtles, birds, mammals"
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waterproof skin legs and a heavier skeleton internal fertilization with amniotic egg
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different finch species have different beaks of different sizes and shapes which tells us...
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different beak shapes are evidence that over time the finch species adapted to different food sources on the island
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genetic evidence supports which explanation for the presence of 13 different finch species
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many years ago a small population of a single finch species migrated to the island and evolved into the current 13 species
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comparing the droughts of 1977 and 1985 showed...
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both droughts resulted in strong natural selection of medium ground finch populations and both droughts resulted in changes to available foods which favored the survival of some medium sized ground finches over others
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how did the grants test their hypothesis that differences in the finch songs can keep different species of finches from breeding with one another
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they played the songs of medium ground finches and cactus finches through a loudspeaker to see which species responded to each song
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the film defines species as populations whose members do not interbreed. What keeps finch species from mating
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individuals only recognize and respond to songs of their own species geographic isolation and different environments led to changes in traits that affected mating
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the following traits can be used to differentiate humans from our closest living primate relatives?
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bipedality larger brains tool use
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which of the following statements about Zinjanthropus and Olduvai Hominid number 7 are true
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the second skull represents a species more closely related to modern humans than the first skull species
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supports the the conclusion that the common ancestor of modern chimps and modern humans live 7 MYA
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analysis of modern humans and chimp protein and DNA sequences suggest that their lineages diverged 7 MYA
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which trait was present in the 3 MYA Autralopithecus fossil named lucy
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lucy was a bipedal hominid and its discovery provided evidence that bipedality preceded the evolution of larger brain size and tool use
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scientist know that the hominid called ardi is about 4.4 million years old because
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by analyzing volcanic deposits above and below the layer containing Ardi
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scientists learned from other fossils found in the same sediment layer as Ardi that
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Ardi lived in a woodland habitat
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which of the following is an accurate statement regarding human evolution
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1.the fossil record contains animals with features that are intermediate between those of modern humans and quadrupedal apes 2.the first humans evolved in africa 3.in the most recent phase of human evolution there has been a greater reliance in culture
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which of the following about the K-T boundary are true
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1. the K-T boundary separates rock layers of the cretaceous period from those of the tertiary period 2. dates back about 66 MYA when the dinosaurs disappeared 3. the K-T boundary in Zumaia, Spain shows an abrupt change in the marine ecosystem
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how do foraminifera found in rock layers above the K-T boundary compare to those in the rock layer below
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foraminifera above the boundary are smaller and less diverse than those below
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why did Dr. Alvarez suggest measuring iridium levels across the K-T boundary
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he wanted to determine how quickly the layer had been deposited
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why was the scientific community slow to accept the asteroid impact hypothesis
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at the time most geologists thought that the earth's systems changed gradually and not rapidly from major catastrophic events
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which evidence is consistent with the asteroid impact hypothesis
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shocked quartz Iridium tektites or melted rock
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what was the critical piece of evidence that supported a hypothesis that an asteroid struck earth 65 MYA
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the Chicxulub crater in Mexico
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which effect of the asteroid impact would cause large numbers of different species of animals and plants to die across the entire planet
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debris from the impact orbiting earth shielding sunlight and halting photsynthesis
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which characteristic was not advantageous for organisims in the million years after the catastrophic asteroid impact
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large body size
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lactase breaks lactose down into
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glucose and galactose
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how would biologist describe someone who is lactase persistent
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someone who is able to digest lactose as an adult
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what did researchers discover about genetic mutations that cause lactase persistence
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they are found in a noncoding regulatory region (switch) near the lactase gene
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which discovery best supports the hypothesis that evolution of the lactase persistence trait was driven by the use of milk as a source of adult nutrition in pastoralist cultures
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ancient pots used to hold milk are about the same age as the lactase persistence mutations
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how could milk drinking have provided strong favorable selection for lactase persistence
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milk is rich in proteins and fats milk could have been a critical food source during times of famine milk is generally safer to drink than water
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in which population would the lactase persistence mutation be more likely to increase in frequency over time due to natural selection
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population that raises wheat and sheep
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