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Bio - Ecology Test 1
Ecology Test 1
| Question | Answer |
|---|---|
| homology | organisms share characteristics because of common descent |
| Convergent evolution | natural selection affects independent evolving species in similar environments in similar ways |
| Which of the following is an observation or inference on which natural selection is based? | Species produce more offspring than the environment can support |
| Which of the following observations helped Darwin shape his concept of descent with modification | South American temperate plants are more similar to South American tropical plants than to European temperate ones. |
| Within six months of effectively using methicillin to treat S. aureus infections in a community, all new S. aureus infections were caused by a resistant strain (MRSA). How can this best be explained? | Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency |
| DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that | humans and chimpanzees share a relatively recent common ancestor. |
| Upper forelimbs of human+bats have similar structures, bones in whales have very different shapes and proportions. Genetic data suggest that all three kinds of organisms diverged from a common ancestor. Most likely explanation for these data? | Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy. |
| Genetic variation | refers to the genetic differences among individuals within a pop |
| nucleotide differences | provide the basis of genetic variation originate when mutation and gene duplication produce new alleles and new genes |
| What do most genetic differences result from | crossing over, independent assortment of chromosomes, and fertilization |
| population | localized group of orgs belonging to one species is united by a gene pool |
| For a pop in the hardy weinberg equilibrium will remain consistent if: | pop is large mating is random mutation is negligible no gene flow no nat selection |
| what tends to reduce genetic variation | genetic drift |
| gene flow | transfer of alleles between pops tends to reduce genetic differences between pops over time |
| sexual selection | can result in secondary sex characteristics that can give individuals advantages in mating |
| balancing selection | occurs when nat select maintains two or more forms in a pop |
| Natural selection changes allele frequencies because some ______ survive and reproduce better than others. | individuals |
| No two people are genetically identical, except for identical twins. The main source of genetic variation among humans is | the reshuffling of alleles in sexual reproduction. |
| If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus? | gene variability = 0%; number of alleles = 1 |
| One population has 25 individuals, all genotype AA; second population has 40 individuals, all genotype aa. populations live far apart but similar environments. Based on this information, the observed genetic variation most likely resulted from | genetic drift. |
| natural selection | process in which individuals with certain inherited traits tend to survive and reproduce at higher rates because of those traits |
| directional selection | favors individ at one extreme of phenotypic range |
| disruptive selection | favors both extremes of phenotypic range |
| stabilizing selection | intermediate variants; acts against the extreme |
| species | group of populations whose individuals may interbreed and produce viable, fertile offspring with each other but not with members of other species |
| reproductive isolation | can form new species though establishment of prezygotic or postzygotic barriers |
| pre zygotic barrier | reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted |
| post zygotic barrier | a reproductive barrier that prevents hybrid zygotes produced by 2 different species from developing into viable, fertile adults |
| allopatric speciation | -gene flow reduced when 2 populations of 1 species become geographically separated from each other -may undergo evolutionary change establishing barriers to reproduction |
| sympatric speciation | - new species originates while remaining in the same geographic area as parent species -can occur via polyploidy, sexual selection, habitat shifts |
| polyploidy | chromosomal alteration where organism possesses more than 2 complete chromosome sets. Result of an accident of cell division |
| hybrid zones | geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry |
| reinforcement | nat select strengthens prezygotic barriers to reproduction, thus reducing hybrid success (fusion is the opposite) |
| The largest unit within which gene flow can readily occur is a | species |
| Males of different species of a fruit fly that live in the same parts of Hawaii have different courtship rituals. rituals involve fighting other males and making stylized movements. What type of reproductive isolation does this represent? | behavioral isolation |
| According to the punctuated equilibria model | most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species. |
| Bird guides once listed the myrtle warbler and Audubon’s warbler as distinct species. Recently, birds have been classified as eastern and western forms of single species. Which of the following pieces of evidence, would be cause for this reclassification? | The two forms interbreed often in nature, and their offspring survive and reproduce well. |
| Which of the following factors would be the most likely to contribute to allopatric speciation? | Different mutations begin to distinguish the gene pools of the separated populations. |
| Plant species A has a diploid chromosome number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be | 28 |
| What happens when amino acids and RNA nucleotides when dipped not hot sand, rock, or clay | they polymerize |
| Protocells | - organic compounds can spontaneously assemble into these - they are membrane bound droplets that have some properties of cells |
| First genetic material | May have self replicating, catalytic RNA (increased though natural selection) |
| radiometric dating | method for determine the absolute age of rocks and fossils based on the half life of radioactive isotopes |
| plate tectonics | continental plates move gradually over time altering the physical geography and climate of Earth, leading to extinctions in some groups and speciate in others |
| mass extinctions | - 5 so far. -Elimination of a large number of species throughout Earth, result of global environmental changes |
| Adaptive radiations | period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill diff ecological roles in their communities |
| exaptation | evolutionary process where a trait originally evolved for one function is repurposed for a new use |
| Fossilized stromatolites | resemble structures formed by bacterial communities that are found today in some shallow marine bays. |
| The oxygen revolution changed Earth’s environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere? | the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules |
| Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia? | India was a separate continent until 45 million years ago |
| Large-scale, worldwide adaptive radiations have occurred in which of the following situations? | after each of the big five mass extinctions |
| Scientists studying the origin of life have accomplished which of the following steps? | abiotic synthesis of RNA’s bases (A, C, G, U) |
| A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of | a change in a developmental gene or in its regulation that altered the spatial organization of body parts. |
| A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from the air-breathing organ (a simple lung) of an ancestral fish is an example of | exaptation |
| How species are classified | Domain, kingdom, phylum, class, order, family, genus, species |
| phylogenetic tree | branching diagram that represents a hypothesis about evolutionary history of a group of organisms |
| homology | similarity due to shared ancestry |
| analogy | similarity due to convergent evolution |
| clade | -monophyletic group that includes an ancestral species and all of its descendants -can be distinguished by their shared derived characters |
| orthologous genes | -homologous genes found in different species as a result of speciation -distantly related species often have many of these |
| paralogous genes | homologous genes within a species that result from gene duplication; such genes can diverge and potentially take on a new function |
| molecular clock | method of estimating the date of past evolutionary events based on the amount of genetic change |
| 3 great domains | bacteria, archaea, eukarya |
| Horizontal Gene Transfer | transfer of genes from one genome to another though mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusions of diff orgs |
| In a comparison of birds and mammals, the condition of having four limbs is | a shared ancestral character. |
| To apply parsimony to constructing a phylogenetic tree, | choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology. |
| Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up | a paraphyletic group. |
| The relative lengths of the frog and mouse branches in the phylogenetic tree in Figure 26.13 indicate that (frog line longer than mouse line) | the homolog evolved more slowly in the mouse lineage. |
| According to the concept of punctuated equilibrium, the sudden appearance of a new species in the fossil record means that | speciation occurred rapidly in geologic time |
| Which of the following sets represents the most likely sequence of events in the origin of life | Synthesis of organic monomers; synthesis of organic polymers; formation of protocells; formation of DNA based genetic systems |
| Which of the following statements most accurately describes a difference between the current atmosphere and that of early Earth | Compared to today, early Earth had an atmosphere richer in gases released from volcanic eruptions |
| Which of the following methods is the most accurate way to measure the age of a relatively recent fossil? | Ratio of carbon 12 to carbon 14 |
| Which of the following lists most likely represents the correct sequence, from earliest to most recent, in the origin of cell organelles and cellular organization | photosynthetic prokaryotes, mitochondria, chloroplasts, multicellular eukaryotes |
| An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to | cause iron in ocean water and terrestrial rocks to rust (oxidize) |
| Which of the following characteristics were most likely present in the first animals that colonized land | ability to resist dehydration and eat producers |
| some beetles and flies have antler like structures on their heads, much like male deer. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of which of the following? | convergent evolution |
| birds and mammals have 4 limbs. Which of the following statements describes this triat | the trait is a shared ancestral character |
| which of the following features permits a gene to act as a molecular clock | a reliable average rate of mutation |
| Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient aerobic bacterium and an ancient cyanobacterium | plantae |
| Which of the following statements best describes darwins theory of evolution by natural selection | darwins theory emphasized that populations vary and change over time |
| which of the following statements best describes evolution | populations change genetically from one generation to the next |
| Which of the following observations most strongly supports the common origin of all life on earth | all organisms use essentially the same genetic code |
| which of the following situations leads to microevoluiton | alleles move between populations that differ in allele frequencies |
| Harmful mutations occur in both diploid and haploid organisms. Which of the following statements about the abundance of harmful mutations in diploid and haploid organisms is accurate? | there are more harmful mutations in populations of diploids than in populations of haploids because the mutations are protected form selection in diploid heterozygotes |
| The effect of which Hardy-Weinberg condition is affected by pop size | genetic drift |
| An earthquake decimates a ground squirrel pop, killing 98%. The surviving pop has broader stripes, on average, than the initial pop. If this is genetically determined, which of the following processes likely caused the change? | bottleneck effect |
| Which of the following provides an example of a mechanical isolation as a prezygotic barrier? | two snails have shells that spiral in diff directions |
| 3 pops of crickets look very similar, but the males have diff courtship songs. If cricket pops were to contact each other in the wild, the songs would most likely function as which type of reproductive isolating mechanism | behavorial |
| which of the following statements best describes macroevolution | macroevolution is above species level |
| two species of frogs belong to the same genus and occasionally mate, but the embryos stop developing after a day then die. Which of the following mechanisms keep the species separate | reduced hybrid viability |
Created by:
bouzianeju