19-23 EVOLUTION Flashcards
Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. What info would best help distinguish between am explanation based in homology versus one based on convergent evolution?
The two species share many proteins in common, and the nucleotides sequences that code for these proteins are almost identical
Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins and seals have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what best describes the flippers of seals and penguins?
Homologous; analogous
Any product of natural selection that increases the relative fitness of an organism in its environment is called
Adaptive trait
A baby born with wrinkled , poorly-formed skin and blood vessels prone to rupturing can be said to have inherited a
Deleterious mutation
Genetic drift will have a progressively larger impact on allele frequencies in a population as
Population size decreases
Mutations that are not passed on from one generation to the next:
Arise in somatic cells
The common house fly belongs to all of the following taxa. Assuming you had access to textbooks or other scientific literature, knowing which of the following should provide you with the greatest amount of detailed information about this specific organism? A.) order Diptera B.) family Muscudae C.) genus Musca D.) class Hexaponda
C
If two populations diverge geographically and/or genetically from each other, and the process continues long enough, they may becomes two different
Species
What’s not true about natural selection?
Natural selection directs evolution by preserving traits acquired during an individual’s lifetime
Swine are vulnerable to infection by bird flu virus and human flu virus , which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined, thereby producing a genetically distinctive virus, which can subsequently cause widespread disease.
The production of new types of flu virus in the manner described about is most similar to the phenomenon of
Gene flow
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1.) which of these originated earliest and appeared suddenly in the fossil record?
2.) what conclusion can be drawn?- ) W
- ) a single clad (a group of species that share a common ancestor) can exhibit both gradualism and punctuated equilibrium
Many new species of desert lizards have arisen from a nonnative population which was introduced into the America southwest. This best describes
Adaptive radiation
A mutation occurred in one member of a species. Few copies of the allele were passed onto offspring. It appears that this mutation______ the evolutionary fitness of the individual.
Had no effect on
In a hypothetical population of 1,000 people, tests of blood-type genes show that 160 have the generator AA, 480 have the genotype AB, and 360 have the genotype BB
- ) what is the frequency of the A allele?
- ) what percentage of the population had type O blood?
- ) If there are 4,000 children born to this generation , how many would be expected to have AB blood under the conditions of Hardy-Weinberg equilibrium?
- ) .400
- ) 0
- ) 1,920
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March. April. May
1st 1st 1st
A likely reason between the speciation between these two sympatric species if frogs is:
Temporal isolation
No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is
The reshuffling of alleles in sexual reproduction
Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from the same embryonic tissues. How do biologists interpret these similarities?
By identifying the bones as being homologous and proposing that humans, bats, and dolphins share a common ancestor
What best summarizes evolution as it is viewed today?
It involves reproduction of the most fit phenotypes
Rank the following from most general to most specific:
- ) gametic isolating
- ) reproductive isolation mechanism
- ) pollen -stigma incompatibility
- ) prezygotic isolating mechanism
2–>4—>1—->3
Postzygotic isolating mechanisms occur when the offspring
Do not survive, inherit different amounts of chromosomes from each parent, and have poor health
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(# of (Measured Variation in Trait)
Individuals)
1.) If the curve in the previous figure shifts to the left or to the right , there is no gene flow , and the population size consequently increases over successive generations. What is/are probably occurring?
2.) What is true of the trait whose frequency distribution in large population appears in pervious figure? It has probably undergone…
- ) direction selection and adaptation
2. ) stabilizing selection
In order for speciation to occur, what is true?
At least one gene, affecting at least one phenotype trait, must change.
The theory of evolution is most accurately described as
An explanation, supported by much evidence , for how populations change over time.
In an environment in which members of a population compete with each other for resources , a change occurs that selects against members that exhibit a particular dominant trait (the trait exhibits complete dominance) what graph would represent this?
A graph showing Heterozygous and Homozygous going down, with homozygous recessive goes up
The Hawaiian islands are a great showcase of evolution because of intense
Adaptive radiation and allopatric speciation
Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Wales have lost their hind limbs. How does natural selection account for these losses?
Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits
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
Which isn’t true?
- ) migration leads to genetic variation
2) dominant genes always occur more frequently in a population than recessive genes - ) nonrandom mating may result in changes in gene frequencies
- ) the hardy-Weinberg law applies to large, stable populations
B
What statement most detracts from the chain that the human appendix is a completely vestigial organ?
The appendix had a large amount of defensive lymphatic tissue
In nature, genes with the potential to produce serious defects are acted against and kept at a low frequency by
Natural selection
Beetle pollinators of a particular plant are attracted to its flowers by their bright orange color. The beetles not only pollinate the flowers, but they mate while insides the flowers. A mutant version of the plant with red flowers becomes more common with passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge so much so that interbreeding is no longer possible. What kind of speciation has occurred, and what has driven it?
Sympatric speciation, habitat differentiation
Crocuses that bloom in the early spring and marigolds that bloom in the summer would definitely experience which type of isolation?
Temporal
What will most likely guarantee that two closely related species will remain distinct biological species?
Reproductive isolation from one another
Reproductive isolating mechanisms are
The ways that gene flow is blocked between populations
In the formula for determining a population’s genotype frequencies , the 2 in the term 2pq is necessary because
The population is diploid
In a hypothetical situation, a certain species of flea feeds only on pronghorn antelope. In rangelands of the western US, pronghorns and cattle often associate with one another. If it should happen that some of these fleas develop a strong preference for cattle blood and mate only with fleas that prefer cattle blood, it is possible that over time____ will occur
Reproductive isolation Sympatric speciation Habitat isolation Prezygotic barriers Cladogenesis (1-5)
Human-Chimp. 1.7 Human-Gorilla. 1.8 Human-gibbon 4.3 Human-rhesus monkey 7.0 Human-tarsier 24.6
- ) based on the data, which is the most distantly related to humans?
- ) which has the most recent common ancestor with humans ?
- ) rhesus monkey
2. ) gorilla
What statement about natural selection is most correct?
Well-adapted individuals leave more offspring, and thus contribute more to the gene pool, than poorly adapted individuals
Mules are relatively long-lived and hardy organisms that cannot, generally speaking, perform successful meiosis. What’s true about them?
They have a relative evolutionary fitness of zero
Given a population that contains genetic variation, what is the correct sequence of the following events?
- ) well adapted individuals leave more offspring than do poorly adapted individuals
- ) a change occurs in the environment
- ) genetic frequencies within the population change
- ) poorly adapted individuals have decreased survivorship
2—> 4—> 1—–> 3
Tongue rolling in humans is due to a dominant allele that is inherited through simple dominance and recessiveness. Why has the frequency of this trait remained fairly constant in the human population?
Tongue-rolling is a neutral variation that does not provide any selective advantage in the human population
The Darwinian fitness of an individual is measured by
The number of its offspring that survive to reproduce
A particular virus that affects the white blood cells of cats occurs in the large domesticated population at a rate of approximately 1-5% where as the disease rate in reduced cheetahs is nearly 60%. What explains the difference in the two populations?
The gene pool of the cheetah is extremely small, therefore the DNA is very similar the ought the population.
In 1400’s small hot peppers were brought the Europe. The bell pepper we eat today are larger, sweeter, and have thicker flesh. How did the change ultimately occur?
Mutations in the genes coding for shape and size occurred over time, producing extra large peppers
Genetic Drift
How allele frequencies fluctuate unpredictably from one generation to the next, reduces genetic variation in smaller populations, can cause harmful alleles to become fixed
Founder effect
Occurs when a few individuals become isolated from a large population
Bottleneck effect
Results from a drastic reduction in population, if population remains small, maybe further affected
Gene flow
Movement of alleles among populations. Reduces genetic various in population over time.
Speciation
Process by which one species splits into two.
Micro/Macroevolution
Micro: consists of changes in allele frequencies in a population overtime
Macro: broad patterns of evolution change above their species level
Apllopatric speciation
Forms a new species while geographically isolated
Sympatric speciation
Takes place in species that live in the same area
Parapetric speciation
Region in which members of different species mate together.
Higher taxa order:
Kingdom (KINGS) Phylum. (Play) Class. (Cards ) Order. (On) Family. (Fat) Genus. (Grey) Species. (Stools)
