Flashcards
Chp 13- How Populations Evolve
Cards in this deck (50)
- 1natural selectionindividuals with certain traits are more likely to survive and reproduce than are individuals who do not have those traits
- 2adaptationsan inherited character that enhances an organism's ability to survive & reproduce in a particular environment
- 3theorya widely accepted explanatory idea that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence
- 4evolutionthe idea that living species are descendants of ancestral species that were different from present-day ones
- 5What was Darwin’s phrase for evolution? What does it mean?Descent with modification. An ancestral species could diversify into many descendant species by the accumulation of adaptations to various environments.
- 6Fossilsimprints or remains of organisms that lived in the past
- 7strataNew layers of sediment cover older ones and compress them into layers of rock
- 8Paleontologistsscientists who study fossils
- 9fossil recordthe chronicle of evolution over millions of years of geologic time engraved in the order in which fossils appear in rock strata
- 10What types of animals do you think would be most represented in the fossil record? Explain your answer.Animals with hard parts, such as shells or bones that readily fossilize, and those that lived in areas where sedimentary rock may form
- 11What anatomical feature did scientists predict in fossils of species transitional between terrestrial and aquatic mammals?Reduced hind limb and pelvic bones
- 12homologySimilarity resulting from common ancestry
- 13homologous structuresfeatures that often have different functions but are structurally similar because of common ancestry
- 14molecular biologythe study of the molecular basis of genes and gene expression
- 15vestigial structuresremnants of features that served important functions in the organism’s ancestors
- 16What is homology? How does the concept of homology relate to molecular biology?Homology is similarity in different species due to evolution from a common ancestor. Similarities in DNA sequences or proteins reflect the evolutionary relationship that is the basis of homology.
- 17evolutionary treea branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms
- 18Are crocodiles more closely related to lizards or birds?Crocodiles are more closely related to birds because they share a more recent common ancestor with birds than with lizards.
- 19artificial selectionthe selective breeding of domesticated plants and animals to promote the occurrence of desirable traits in the offspring
- 20Compare artificial selection and natural selection.In artificial selection, humans choose the desirable traits and breed only organisms with those traits. In natural selection, the environment does the choosing: Individuals with traits best suited to the environment survive and reproduce most successfully, passing those adaptive traits to offspring.
- 21In what sense is natural selection more an editing process than a creative process?Natural selection cannot create beneficial traits on demand but instead “edits” variation in a population by selecting for individuals with those traits that are best suited to the current environment.
- 22mutationa change in the genetic information encoded in the nucleotide sequence of DNA
- 23sexual reproductioncrossing over, independent orientation of homologous chromosomes at metaphase I of meiosis, and random fertilization
- 24What is the ultimate (original) source of genetic variation? What is the source of most genetic variation in a population that reproduces sexually?Mutation; unique combinations of alleles resulting from sexual reproduction
- 25populationa group of individuals of the same species that live in the same area and can potentially interbreed
- 26gene poolall copies of every type of allele at every locus in all members of the population
- 27microevolutiona change in a population's gene pool over generations
- 28Why can’t an individual evolve?Evolution involves changes in the genetic makeup of a population over time. An individual’s genetic makeup rarely changes during its lifetime.
- 29Hardy-Weinberg equilibriumthe state of a population in which frequencies of alleles & genotypes in a population remain constant from generation to generation
- 30the Hardy-Weinberg equation:p2 + 2pq + q2 = 1
- 31Which is least likely to alter allele and genotype frequencies in a few generations of a large, sexually reproducing population: gene flow, mutation, or natural selection? Explain.Mutation. Because mutations are rare, their effect on allele and genotype frequencies from one generation to the next is likely to be small.
- 32Which term in the Hardy-Weinberg equation—p2, 2pq, or q2—corresponds to the frequency of individuals who have no alleles for the disease PKU?The frequency of individuals with no PKU alleles is p2.
- 33genetic driftchance events can cause allele frequencies to fluctuate unpredictably from one generation to the next
- 34bottleneck effecta drastic reduction in population size
- 35founder effectgenetic drift that occurs when a few individuals become isolated from a larger population & form a new population whose gene pool is not reflective of that of the original population
- 36gene flowthe transfer of alleles from one population to another as a result of the movement of individuals or their gametes
- 37How might gene flow between populations living in different habitats actually interfere with each population’s adaptation to its local environment?The introduction of alleles that may not be beneficial in a particular habitat prevents the population living there from becoming fully adapted to its local conditions.
- 38relative fitnessthe contribution an individual makes to the gene pool of the next generation
- 39Explain how the phrase “survival of the fittest” differs from the biological definition of relative fitness.Survival alone does not guarantee reproductive success. An organism’s relative fitness is determined by its number of fertile offspring and thus its relative contribution to the gene pool of the next generation.
- 40Directional selectionnatural selection in which individuals at one end of the phenotypic range survive & reproduce more successfully than do other individuals
- 41Stabilizing selectionnatural selection that favors intermediate variants by acting against extreme phenotypes
- 42Disruptive selectionnatural selection in which individuals on both extremes of a phenotypic range are favored over intermediate phenotypes
- 43sexual selectiona form of natural selection in which individuals with certain traits are more likely than other individuals to obtain mates
- 44sexual dimorphismmarked differences between the secondary sex characteristics of males & females
- 45Males with the most elaborate ornamentation may garner the most mates. How might choosing such a mate be advantageous to a female?An elaborate display may signal good health and therefore good genes, which in turn could be passed along to the female’s offspring.
- 46Explain why the following statement is incorrect: “Antibiotics have created resistant bacteria.”The use of antibiotics did not cause bacteria to make new alleles. Rather, antibiotic use has increased the frequency of alleles for resistance that were already naturally present in bacterial populations.
- 47Balancing selectionnatural selection maintains stable frequencies of two or more phenotypic forms in a population
- 48Heterozygote advantagea type of balancing selection in which heterozygous individuals have greater reproductive success than either type of homozygote
- 49Why would natural selection tend to reduce genetic variation more in populations of haploid organisms than in populations of diploid organisms?All alleles in a haploid organism are phenotypically expressed and are hence screened by natural selection.
- 50Humans owe much of their physical versatility and athleticism to their flexible limbs and joints. But we are prone to sprains, torn ligaments, and dislocations. Why?Adaptations are compromises: Structural reinforcement has been compromised as agility was selected for.
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- Flashcards on Chp 13- How Populations Evolve , created by Kyannah Harris on 21/03/2020.
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- Kyannah Harris · Mar 2020
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- Mar 21, 2020
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