DAT BC bio bites evolution

Genetic drift has a much bigger impact on populations of what size? A. Small B. Large Check Answer

small Genetic drift is a change in allele frequencies in a gene pool by chance. It has a much bigger impact on small populations because infrequently-occurring alleles will have a higher chance of being lost (i.e. removed from the population).

Macroevolution looks at changes that occur at a level that is at or higher than which of the following?

species Macroevolution looks at changes that occur at a level that is at or higher than species. Recall the 7 levels of taxonomy (Kingdom, Phylum, Class, Order, Family, Genus, Species). Since we are at least at the level of species, evolution will take time. We need to look from a long-term perspective to see macroevolutionary patterns.

Which type of natural selection is portrayed by a bell curve?

stabilizing

An average newborn weighs around 3.5 kg, while babies who are born too small are fragile and babies who are born too big may face complications during the birth process. This is an example of what type of natural selection?

stabilizing Stabilizing selection is the type of selection where mainstream is favored, oddballs are selected against. For example, an average newborn weighs around 3.5kg, babies who are born too small are fragile and risk losing too much body heat, whereas babies who are born too big may face complications during the birth process.

Which type of prezygotic isolation prevents fertilization because species breed and reproduce at different times/seasons? A. Behavioral isolation B. Temporal isolation C. Mechanical isolation D. Habitat isolation E. Gamete isolation Check Answer

temporal isolation Temporal isolation: Species breed and reproduce at different times/seasons. "Well, if you are only active past midnight whereas I am an early bird, I don't think we are right for each other."

Which of the following statements does NOT describe the hypothesis of use and disuse? A. The more used the body part is, the more it will develop. B. The notion of use and disuse is correct. C. A giraffe's neck grows longer when it tries to feed from higher trees. D. The less used the body part is, the more weakened it will be. Check Answer

the notion is correct he use and disuse hypothesis is NOT correct. It states that: The more used the body part is, the more it will develop i.e. a giraffe's neck grows longer when it tries to feed from higher trees. The less used the body part is, the more weakened it will be i.e. certain species of monkeys didn't use their tails much, so through disuse that species evolved to not have tails.

Which of the following accurately describes hybrid F2 breakdown?

the offspring of the hybrid zygote suffers from decreased fitness Hybrid F2 breakdown: F2 refers to the next generation of hybrids; in this case, even if hybrids can reproduce, their offspring would suffer from decreased fitness.

Which of the following describes the term "gene flow"?

the process of moving alleles between populations through individual's migration Gene flow is the process of moving alleles between populations through individuals' migration. You can think of gene flow like how we are living in a global village nowadays — people emigrate and immigrate around the world and breed amongst different ethnicities. This causes alleles to mix and eventually make variations between populations smaller.

If two different species are reproductively separated, which of the following is true?

the respective gene pool of each species is isolated remember, species are individuals that can interbreed. Therefore, two different species are reproductively separated, which means that their respective gene pool is also isolated, denying gene flow between species.

Which of the following is NOT one of the requirements for natural selection to occur? A. Organisms must have variation in traits. B. Traits must be heritable. C. There is more supply than demand. D. Organisms are constantly competing for survival. E. Differences in traits impact reproductive success and/or survival. Check Answer

there is more supply than demand Natural selection chooses the fittest being. But in order for natural selection to occur, there are 4 requirements: There is more demand than supply, i.e. organisms are constantly competing for survival. There is a difference in the level of fitness, i.e. organisms must have variation in traits. Traits must be heritable. The variation of traits must be significant to reproduction and/or survival.

Which of the following is an example of aposematic coloration?

thr bright coloring of poison dart frogs Aposematic coloration (warning coloration) is a vibrant, bright coloration of poisonous animals, which warns predators that they are poisonous. An example of aposematic coloration is the bright coloring of poison dart frogs.

Jean-Baptiste Lamarck proposed which two hypotheses of evolution?

use and disuse, inheritance of acquired traits

In what situation does Mullerian mimicry often occur?

when different poisonous species share a common predator Mullerian mimicry occurs when different poisonous species that share a common predator evolve to resemble each other. This way, it is easier for the predator to learn to avoid these species. An example is of a stinging bee and a stinging wasp, which have evolved to share similar coloring and body size.

Suppose that the green color in peas is dominant, and the yellow color is recessive. Consider a population of peas that is 84% green and 16% yellow. What is the frequency of the recessive allele?

0.4 Say we're told that there is a population of peas that is 84% green and 16% yellow. And the question asks us what is the frequency of the recessive allele, i.e. q? Approach: We know that both homozygous dominant (GG) or heterozygous (Gg) peas will appear green. However, yellow is the recessive color, so they have to be homozygous recessive (gg). We know that q²= frequency of gg Therefore, knowing that 16% of the population is yellow: q2 = 16% = 0.16 q = √0.16 = 0.4 q = 0.4 which is our frequency of q (recessive allele) in the population

How many copy/copies of each chromosome does a diploid organism have, and how many allele(s) does it have for each gene? A. One; one B. One; two C. Two; two D. Two; one Check Answer

2, 2 Many animals are diploid, meaning that they have two copies of each chromosome, and therefore two alleles for each gene.

Suppose that the green color in peas is dominant, and the yellow color is recessive. Consider a population of peas that is 84% green and 16% yellow. What is the heterozygous frequency?

48% Say we're told that there is a population of peas that is 84% green and 16% yellow. And the question asks us what is the heterozygous frequency, i.e. 2pq? Approach: We know that both homozygous dominant (GG) or heterozygous (Gg) peas will appear green. However, yellow is the recessive color, so they have to be homozygous recessive (gg). We know that q²= frequency of gg Therefore, knowing that 16% of the population is yellow: q2 = 16% = 0.16 q = √0.16 = 0.4 q = 0.4 which is our frequency of q (recessive allele) in the population Let's go back to plug this into p + q = 1 Since q = 0.4: p + q = 1 p + 0.4 = 1 p = 0.6 Now let's calculate our heterozygous frequency, 2pq. Plug this into our heterozygous frequency component of the formula 2pq. Substitute in the values we've determined: p = 0.6 and q = 0.4 2pq = 2(0.4)(0.6) = 0.48 2pq = 48% These two formulas are only valid if the population is in Hardy-Weinberg equilibrium.

Which scientist proposed catastrophism?

Baron Cuvier proposed the theory of catastrophism.

Respiration can be seen in many eukaryotes like plants and animals, which provides evidence that both plant and animal eukaryotes evolved from a common eukaryotic ancestor. Which of the following terms describes respiration? A. Vestigial structure B. Conserved DNA region C. Common conserved pathway D. Embryological similarity E. Geographical barrier Check Answer

Common conserved pathway A form of biochemical evidence are common conserved pathways in species that are related. For example, respiration (Kreb's cycle, ETC) can be seen in many eukaryotes like plants and animals, which provides evidence that both plant and animal eukaryotes evolved at one point from a common eukaryotic ancestor.

The image below represents which type of natural selection? (*red = before, blue = after)

Disruptive selection describes changes in a population where the extremes for a trait are favored over intermediate values. In the diagram, we can see that the middle shellfish is selected against, while the extreme colors are favored.

Which of the following is NOT an example of analogous structures? A. Cat leg vs. praying mantis leg B. Bird wing vs. bat wing C. Forearm of a bird vs. forearm of a human Check Answer

Forearm of a bird vs. forearm of a human Analogous structures are structures that have the same functions but are not derived from a common ancestor. For instance, both birds and bats evolved to have wings, but they originated from different lineages. Another example are the legs of a cat and those of a praying mantis. The forearm of a bird and that of a human are homologous structures because they are derived from a common ancestor.

Which of the following is NOT a way in which sexual reproduction creates genetic diversity? A. Crossing over of homologous chromosomes during prophase I B. Random joining of gametes C. Formation of the synaptonemal complex during prophase II D. Independent assortment Check Answer

Formation of the synaptonemal complex during prophase II Sexual reproduction will create genetic diversity in 3 ways: Crossing over via formation of synaptonemal complex between homologous chromosomes (occurs in prophase I only) Independent assortment (occurs in metaphase I and II) Random joining of gametes

Which of the following correctly describes evolution?

Gradual change of heritable traits in population over successive generations Evolution is the gradual development and change of heritable traits in populations over successive generations. It is a long process that brings about biodiversity.

Consider the sickle cell anemia genes thriving in Africa. AA genotypes give normal hemoglobin, SS genotypes give sickle cell anemia, and AS genotypes offer resistance against malaria without causing sickle cell anemia. What is this an example of? A. Minority advantage B. Heterozygote advantage C. Hybrid advantage D. Neutral variations Check Answer

Heterozygote advantage Heterozygote advantage is when a heterozygote form is more fitted to the environment than either homozygote forms. An example would be sickle cell anemia genes thriving in Africa. AA genotypes give normal hemoglobin, SS genotypes give sickle cell anemia (likely to die before puberty), whereas AS genotypes are beneficial because they offer resistance against malaria - a common killer in Africa - without causing sickle cell anemia.

Which of the following accurately describes hybrid advantage? A. Offspring of two different strains of organisms are superior B. Minimizes heterozygous advantage C. Similar to directional selection Check Answer

Offspring of two different strains of organisms are superior A hybrid is a result of breeding between two different strains of organisms. More breeding options = more variety! According to hybrid advantage, the offspring is usually more superior due to the combination of different genes — avoiding deleterious homozygous diseases and maximizing heterozygous advantage.

What term describes the study of fossils? A. Embryology B. Histology C. Paleontology D. Comparative anatomy E. Ecology Check Answer

Paleontology

Which of the following describes the process of sexual selection?

Sexual selection occurs in nature when there is differential, non-random mating between a male and a female.

Which of the following accurately describes the term "balanced polymorphism"? A. When an organism has multiple alleles for a gene B. Type of reproductive isolation that prevents fertilization even if mating is attempted C. When a new population is established by a very small number of individuals from a larger population D. Situation in which different phenotypes within the members of a population can be maintained Check Answer

Situation in which different phenotypes within the members of a population can be maintained 'Poly' = many and 'morphism' = forms; hence, 'polymorphism' = many different forms. A balanced polymorphism means that different phenotypes within the members of a population can be maintained, through these advantages: Heterozygote advantage Minority advantage Hybrid advantage Neutral variations

Which of the following does NOT accurately describe sexual selection? A. The cost of fathering an offspring is very low for most males. B. Females carefully pick the superior males to boost the quality of her offspring. C. Compared to males, females have a limited capacity to reproduce. D. Males increase their fitness by boosting the quantity of their offspring. E. The traits selected for must be favorable for survival. Check Answer

The traits selected for must be favorable for survival. The traits selected for may be favorable for reproduction but not for survival. Sexual selection is different from natural selection because the evolutionary changes each gender makes could lead to less survival (despite making them more competitive for sex). For example, consider the vibrant colors of a male peacock's feathers - it's great for attracting mates, but makes them more easily spotted by predators. In nature, females can be very picky because they are the ones who choose which male to mate with. This is because compared to males, females have a limited capacity to reproduce due to the relatively long labor period. Hence, females need to carefully pick the superior males to boost the quality of her offspring. Since the cost of fathering an offspring is very low for most male animals, males increase their fitness by boosting the quantity of his offspring (trying to impregnate as many females as possible).

Which of the following describes the term "bottleneck effect"? A. When a new population is established by a very small number of individuals from a larger population B. When speciation occurs due to the presence of a geographical barrier C. When there is a disaster that kills off most of the population D. The process of moving alleles between populations through individuals' migration Check Answer

When there is a disaster that kills off most of the population Bottleneck effect is when there is a disaster that kills off most of the population.

Which of the following describes convergent evolution?

When two unrelated species grow more and more alike due to adaptations in similar environments Convergent evolution is when two completely unrelated species grow more and more alike due to adaptations in similar environments.

Which of the following is NOT true about the founder effect? A. Type of genetic drift B. Involves random increase or decrease of allele frequencies by chance C. A small group of individuals immigrate and join another population Check Answer

a small group of individuals immigrate and join another population A special type of genetic drift is the "founder effect," which occurs when a small group of emigrating individuals start their own population, and the new population does not reflect the allele frequencies of the original population from which they left.

Which type of speciation occurs due to the presence of a geographical barrier?

allopatric Allopatric speciation is when speciation occurs due to the presence of a geographical barrier. The geographical barrier will stop populations from breeding. As they continue to live in their respective environments, they are subject to the effects of natural selection and will gradually differ from the original group that they used to belong to. Eventually, they will become a new species. Being physically separated is probably the most straightforward way to stop species from mating. However, there are still other ways that will prevent mating and induce speciation without necessarily being isolated. In the case of sympatric speciation, speciation occurs WITHOUT the presence of a geographical barrier.

Which of the following is NOT true about mutations? A. Occur randomly B. Always unfavorable C. Changes in genetic code Check Answer

always unfavorable Mutation are changes in the genetic code that happen randomly. Mutations can be harmful or helpful to the organism. Favorable mutations are more likely to be passed on to the next generation, while unfavorable mutations are not.

A clade on a phylogenetic tree consists of which of the following? A. An ancestor only B. The descendants from an ancestor only C. An ancestor and all descendants from that ancestor Check Answer

an ancestor and all descendants every cluster you see on a phylogenetic tree is called a clade, also known as a monophyletic group . It includes an ancestor and all descendants from that ancestor. Therefore, a clade could be as big as the entire tree, or just a small branch at the tip of the tree.

A paraphyletic group on a phylogenetic tree consists of which of the following? A. An ancestor only B. The descendants of different ancestors C. An ancestor and all descendants from that ancestor D. An ancestor and some, but not all, of its descendants Check Answer

an ancestor and some, but not all, of its descendants

Which term describes the gradual evolution of a species that continues to exist as an interbreeding population?

anagenesis The process of evolutionary lineages splitting apart and forming new clades is known as cladogenesis. This stands in contrast to anagenesis, which describes the gradual evolution of a species that continues to exist as an interbreeding population.

Which type of selection is usually carried out by humans when they selectively breed for favorable traits in an organism?

artificial As the name suggests, artificial selection is not a type of natural selection. Artificial selection is usually carried out by humans when they selectively breed for favorable traits, such as breeding for certain traits in dogs. The artificial selection of dogs with certain characteristics to create a new, adorable dog breed for example.

Which of the following accurately describes directional selection?

as evolution occurs, the population evolves to favor traits in one direction one extreme favor Directional selection is the type of selection where one extreme is favored (as evolution occurs, the population evolves to favor traits in one direction).

Which of the following is NOT a source of genetic variation? A. Mutation B. Asexual reproduction C. Balanced polymorphism D. Polyploidy Check Answer

asexual reproduction Sources of genetic variation: Mutation Sexual reproduction Balanced polymorphism Polyploidy

Which type of mimicry describes when a non-harmful animal mimics the coloring of a harmful animal?

batesian Batesian mimicry: A non-harmful animal mimics the coloring of a harmful animal. An example is a harmless fly that mimics the coloring of a stinging bee.

Courtship rituals are a component of which type of reproductive isolation? A. Mechanical isolation B. Hybrid sterility C. Hybrid mortality D. Behavioral isolation E. Gamete isolation Check Answer

behavioral isolation Behavioral isolation: Many species perform courtship rituals to signal to their partners, such as singing songs in birds or pheromones in ants. Different species will not perform the right type of rituals, hence preventing mating.

Which type of evidence explains the spread of different species throughout the world?

bigeography Biogeography evidence explains the spread of different species throughout the world. As the supercontinent Pangea separated into 7 different continents, living organisms were also separated. As the organism's environment changed, evolution took place so that the organisms could better adapt to their new habitats.

Polar bears are only found in the North Pole, but penguins are found in the South Pole. Which type of evidence explains this phenomenon?

bigeography Biogeography evidence explains the spread of different species throughout the world. For example, both penguins and polar bears thrive in bitter cold environments. But why are polar bears only found in the North Pole whereas penguins are in the South Pole? This is because geographical barrier made it impossible to go to the other pole, so they each adapted to their respective surroundings.

Conserved DNA regions are an example of which type of evidence that supports the theory of evolution? A. Fossils B. Biogeography C. Comparative anatomy D. Biochemical E. Embryology Check Answer

biochemical Biochemical is the newest type of evidence that supports the theory of evolution, as scientific analysis methods has gotten more and more advanced. When we compare DNA sequences in genomes, we see conserved DNA regions across species which are related. The higher the similarity, the stronger the relatedness. Chimpanzees have roughly 98% similarity with humans, showing a strong lineage connection.

During the Industrial Revolution, white tree bark was covered by soot and turned black. The frequency of which type of peppered moths increased as a result? A. Black peppered moths B. White peppered moths Check Answer

black peppered moths If every individual is equally fit, then there would be no way to select the "fittest" one. Therefore, organisms must have variation in traits. Variation among members of the population differentiates their ability to compete to survive. For example, during the Industrial Revolution, white tree bark was covered by soot and turned black. At that time, the frequency of black peppered moths increased because of its camouflage color. After the Industrial Revolution was over, pollution was cleared and the white peppered moths became favored by natural selection. This shows how different variations are favored under different environments.

Which of the following populations is considered to be under Hardy-Weinberg equilibrium? A. Population where neither p + q = 1 nor p2 + 2pq + q2 = 1 hold true B. Population where both p + q = 1 and p2 + 2pq + q2 = 1 hold true C. Population where p + q = 1 holds true, but p2 + 2pq + q2 = 1 does not D. Population where p2 + 2pq + q2 = 1 holds true, but p + q = 1 does not Check Answer

both hold true f both of the equations hold true, then the population would be under Hardy-Weinberg equilibrium. However, if any of the two is not met, then the population is not under Hardy-Weinberg equilibrium.

A forest fire kills off a population of red squirrels, and by chance two albino squirrels survive, resulting in a much smaller gene pool. This is an example of which of the following?

bottleneck effect Bottleneck effect is when there is a disaster that kills off most of the population. For example, a forest fire kills off the majority of a population of red squirrels, and by chance two albino squirrels survive. The new population may be albino (if new squirrels don't migrate to this area). What's left is a handful of lucky individuals that survived, and a much smaller gene pool. Some alleles may be lost from this (by chance).

What is another term for cryptic coloration?

camoflauge Camouflage (cryptic coloration) allows animals to avoid visual detection through matching of their appearance to the environment. An insect appearing stick-like is an example of this.

What does the theory of catastrophism state is an effect of sudden catastrophic events? A. Selectively killed off species B. Caused mass extinction events C. Extinguished all life in an area Check Answer

caused mass extinction events The theory of catastrophism was based on observations of fossil patterns, and it proposed that there must have been sudden catastrophes that happened spontaneously throughout history to cause mass extinction of species in those areas (dinosaurs, for example). The different populations were shaped by what catastrophes had occurred, and what random organisms survived. After the catastrophe, the landscape is drastically changed and new life forms will eventually populate the area, giving off new fossil specimens.

Evolution refers to the heritable changes in populations of species over generations. Specifically, what kinds of changes does this refer to?

changes in alleles frequencies To be specific, evolution refers to the changes in allele frequencies in populations over time. For example, the allele that codes for a white fur coat will become more common as a population of foxes begins to live in the arctic.

Which scientist proposed the theory of natural selection? A. Thomas Malthus B. Gregor Mendel C. Charles Darwin D. James Hutton E. Charles Lyell Check Answer

charles darwin Charles Darwin proposed the theory of natural selection. In developing his theory of evolution through natural selection, Darwin pulled heavily from ideas that originated from Thomas Malthus.

Which phylum contains all organisms with a notochord? A. Chordata B. Annelida C. Arthropoda D. Mollusca E. Rotifera Check Answer

chordata

Camouflage, aposematic coloration, and mimicry are examples of which of the following terms? A. Parallel evolution B. Divergent evolution C. Convergent evolution D. Coevolution Check Answer

coevolution Coevolution is when two species impart selective pressures on each other, resulting in the evolution of both species. Camouflage, aposematic coloration, and mimicry are examples of coevolution.

The development of analogous structures is a feature of which type of evolution? A. Convergent evolution B. Parallel evolution C. Divergent evolution D. Coevolution Check Answer

convergent Convergent evolution is when two completely unrelated species grow more and more alike (development of analogous structures) due to adaptations in similar environments. Analogous, in biology, is defined as having the same or corresponding roles (function) but do not share a common evolutionary origin.

how does random mating affect the chances of a specific allele changing in frequency?

decreases Random mating means that individuals do not seek a particular type of individual to mate with. For example, they do not mate only with nearby individuals or express sexual selection. Random mating decreases the chances of a specific allele changing in frequency. Therefore, it is a condition for Hardy-Weinberg equilibrium.

During the Industrial Revolution, white tree bark was covered by soot and turned black. As a result, moths eventually developed darker colors to blend in. This is an example of which type of natural selection?

directional Directional selection is the type of selection where one extreme is favored (as evolution occurs, the population evolves to favor traits in one direction). For example, black color is more favorable than white color during the Industrial Revolution (where there is lots of black soot around) for moths, so moths eventually develop darker colors that blend in.

After you take penicillin for an infection, there are still drug-resistant bacteria that survive, reproduce, and pass on their resistance genes. This is an example of which type of natural selection?

directional selection Directional selection is the type of selection where one extreme is favored (as evolution occurs, the population evolves to favor traits in one direction). An example would be bacterial resistance to a certain type of antibiotics. As we take penicillin for an infection, there might be a bacterium that is genetically resistant to penicillin. After taking the drug, mainly drug resistant bacteria survive and are directionally selected to reproduce and pass on their resistance genes.

The image below represents which type of natural selection? (*red = before, blue = after)

directional selection This is a diagram that shows directional selection where giraffes evolve to be taller (which enables them to reach leaves of taller trees and which contributes to fitness). Note how one extreme is favored.

In low-vegetation areas, predators can detect snails with black shells, so the ones with white shells will thrive. In high-vegetation areas, predators feed on snails with white shells, so the ones with black shells will thrive. This is an example of which type of natural selection? A. Stabilizing selection B. Directional selection C. Disruptive selection Check Answer

disruptive Disruptive selection is the type of selection that is the exact opposite of stabilizing selection. For example, there is a breed of snails that live both in low-vegetation areas (grassfields, meadow) and high-vegetation areas (forests). In low-vegetation areas, predators can detect snails with black shells, so snails with white shells will thrive. In high-vegetation areas, predators feed on snails with white shells, so the ones with black shells will flourish. The two extremes are favored.

Which of the following is the exact opposite of stabilizing selection? A. Sexual selection B. Stabilizing selection C. Artificial selection D. Disruptive selection E. Directional selection Check Answer

disruptive Disruptive selection is the type of selection that is the exact opposite of stabilizing selection. In this case, oddballs (rare traits) are favored, while mainstreams (common traits) are not.

Minority advantage is analogous to which type of natural selection? A. Disruptive B. Stabilizing C. Directional Check Answer

disruptive oddballs Minority advantage is when a rare or extreme phenotype offers higher fitness than common phenotypes, just as we saw in disruptive selection.

What term describes when species diverge from a common ancestor through speciation?

divergent evolution Divergent evolution is when species diverge from a common ancestor through speciation.

Which of the following is NOT a type of prezygotic isolation? A. Habitat isolation B. Divergent isolation C. Temporal isolation D. Behavioral isolation E. Gamete isolation Check Answer

divergent isolation Some types of prezygotic isolation include: Habitat Isolation Temporal Isolation Behavioral Isolation Mechanical Isolation Gamete Isolation

Why is diploidy beneficial?

dominant alleles can mask the effect of recessive alleles Diploidy is beneficial because the dominant allele can mask the effect of the recessive allele, which is very helpful in cases where the recessive allele is harmful, such as sickle cell anemia. Imagine if we only had one gene for hemoglobin; people who happen to have one copy of the sickle cell allele would suffer from that disease. But since we are diploid, we would need two copies of the sickle cell gene to have the disease — greatly reducing the number of sickle cell patients!

Both humans and fish embryos have a gill slit at some point of their development. Which type of evidence explains this phenomenon?

embryology Embryological similarities are observed during the development stage in related organisms. From the outside, there is a huge physical difference between an adult human and a fish. But on the embryology level, we can see a lineage because all chordates have a gill slit at some point of their development. In the image below, notice how similar all of these different chordates are in their early embryo appearance.

Which of the following environmentally acquired characteristics can be passed down from parent to offspring?

epigenetic changes from smoking As a general rule, environmentally acquired characteristics are not heritable; they are changes to the organism, but don't represent a heritable change because the use/disuse doesn't change the genetic code, ie. the DNA. There are a few exceptions to this. For example, some epigenetic changes (that is, changes that do not actually change the nucleotide sequence of DNA) are heritable. But in general, environmentally acquired characteristics aren't heritable.

At what level does evolution take place?

evolution occurs in populations Individuals do not evolve, populations evolve over generations. Those organisms better adapted to survive and reproduce are more successful in passing on their genes, resulting in the evolution of populations over time.

Which of the following accurately describes the term "ichnofossils"?

fossils of plant or animals There are two types of fossils — one is fossils of the actual remains of the animal, another one is fossils of their traces (ichnofossils), which records details like footprints and nests.

A couple of individuals from a population migrate to and settle in a new location, resulting in a much smaller gene pool than their original population. This describes which of the following terms? A. Gamete isolation B. Bottleneck effect C. Punctuated equilibrium D. Divergent evolution E. Founder effect Check Answer

founder effect founder effect is when there are a couple of individuals that migrate to and settle in a new location, these individuals will have a much smaller gene pool than their original population. The successive generations will descend from the founders.

Mammalian oocytes have a structure called the zona pellucida that blocks the binding of sperm from alien species. What is this an example of?

gametic isolation Gamete isolation: This is when gametes cannot recognize and fertilize each other. Mammalian oocytes have a structure called the zona pellucida that blocks the binding of sperm from alien species; this is an example of gametic isolation

What term describes a state of no change in allele frequencies? A. Static evolution B. Balanced polymorphism C. Microevolution D. Gene equilibrium E. Genetic drift Check Answer

gene equilibrium n gene equilibrium, there is no change in allele frequencies, hence there would be no evolution.

Hardy-Weinberg equilibrium requires large populations to minimize the effects of what?

genetic drift Large populations minimize the effects of genetic drift. Genetic drift is the random increase or decrease of allele frequencies due to chance.

Many different species are restricted to only one layer of the canopy in tropical rainforests. This is an example of which type of reproductive isolation?

habitat isolation Habitat isolation: Even if two species reside in the same geographical area, if they occupy different habitats it will hinder mating. For example, many different species are restricted to only one layer of the canopy in tropical rainforests.

Which of the following accurately describes analogous structures?

have the same function but not derived from common ancestor

Vestigial structures can often be categorized as which other type of structure?

homologous Vestigial structures are structures that exist, but do not serve a purpose in an organism. They are often homologous to structures that are functional in other organisms because they are derived from a common ancestor.

Which of the following may or may not perform the same function, but are derived from a common ancestor?

homologous structures Homologous structures are structures that may or may not perform the same function, but are derived from a common ancestor. For example, the forearm of a bird and the forearm of a human have different functions, but both have the same ancestral origin.

Which of the following is NOT a type of postzygotic isolation? A. Hybrid mortality B. Hybrid sterility C. Hybrid F1 breakdown D. Hybrid F2 breakdown Check Answer

hybrid F1 breakdown There's always needs be a plan B for things if plan A fails. Postzygotic isolation is the backup in case a hybrid zygote actually forms. Hybrid mortality Hybrid sterility Hybrid F2 breakdown

When does hybridization lead to the formation of a new species?

hybrid is fertile and more fit than purebred this is a similar idea as polyploidy in plants, but hybridization also occurs in animals. Some hybrids are infertile (mules), and are not defined as a new species. However, some hybrids could be more fit than the purebred species, and eventually form its own line of species.

Which term describes when a hybrid zygote is not viable and dies before reaching reproductive age?

hybrid mortality Hybrid mortality: This is when a hybrid zygote is not viable and dies before reaching reproductive age. Usually, different species have different # of chromosomes; when gametes with a different # of chromosome fuse, the maternal and paternal genetic information cannot match properly.

The mule is an example of which type of postzygotic isolation?

hybrid sterility Hybrid sterility: This is when a hybrid zygote is sterile and cannot reproduce. The most well-known example would be the mule (hybrid of a horse and a donkey); it's viable (doesn't die), but is infertile (can't produce new offspring).

What sorts of evolutionary relationships are depicted in phylogenetic trees?

inferred relationships According to the definition, a phylogenetic tree is a branch diagram that shows the inferred evolutionary relationship between different taxa. Here, the word inferred is very important, because we are tracing back history. Biologists can only infer the relationship between species using bits and pieces of the biological evidences of evolution we mentioned earlier (fossils, anatomical structures, etc). They cannot go back in time to check their work

If a giraffe stretches its neck continually, it will develop a longer neck, and will pass on the long neck to its offspring. This describes which hypothesis? A. Catastrophism B. Natural selection C. Exponential population growth D. Inheritance of acquired traits Check Answer

inheritance of acquired traits Jean-Baptiste Lamarck believed that whatever characteristics the organism acquires throughout its life (through use and disuse) will be passed onto its offspring. According to the theory of the inheritance of acquired traits, if a giraffe stretches its neck continually, it will develop a longer neck, and will pass on the long neck to its offspring.

What is true of a population that experiences no gene flow?

isolated from other populations A condition for Hardy-Weinberg equilibrium is for there to be no migration or mixing with individuals of other populations. This can also be written as no gene flow. To ensure that there is no gene flow, the population must be isolated. No amount of gene flow into or out of the population can occur.

When designing a phylogenetic tree, what is preferred?

least assumptions; minimal homoplasy

Which of the following accurately describes stabilizing selection? A. The mainstream trait is favored. B. One extreme trait is favored. C. Rare traits are favored. Check Answer

mainstream favored

Which type of isolation prevents fertilization because male and female genitalia are not compatible between different species?

mechanical

Polyploidy often results from nondisjunction during which type of cell division

meiosis Polyploidy often results from nondisjunction when chromosomes separate during cell division, specifically meiosis. Let's imagine plant A, which normally contains 10 chromosomes (2n = 10). During meiosis, if nondisjunction occurs and two of the four gametes have 0 chromosomes, the other two will have 10 chromosomes (2n). Whereas under normal conditions all four gametes should each have 5 chromosomes (n). So what happens next? If one of the 2n gametes fuses with another normal n gamete, there will be a 15 chromosome (3n) zygote. This 3n zygote will be sterile, unless it encounters another polyploidy 3n gamete. This will result in reproductive isolation and could eventually result in polyploidy speciation, if two 3n organisms meet and are reproductively compatible.

In which form of evolution can genes change after just one generation?

microevolution macroevolution looks at changes that occur at a level that is at or higher than species, which takes a long time. This is unlike microevolution, where a population's allele frequencies can change after just one generation.

Predators can develop search images according to the most common appearance of their prey. What type of genetic variation does this cause in the prey?

minority advantage An example of minority advantage is when predators develop a "search image" for their preys according to the most common appearance, and they hunt accordingly. Because of this, prey that have a rare phenotype are able to escape the predator, and are therefore more 'fit'.

Which type of advantage causes rare phenotypes to cycle between low and high frequencies?

minority advantage Minority advantage is when a rare phenotype offers higher fitness than common phenotypes. However, as the rare allele increases in frequency, it then becomes common again, and will be selected against, leading to a decrease in frequency; hence, rare phenotypes cycle between low and high frequencies.

If the world had an infinite supply of resources, what would happen?

natural selection would not occur If the world had an infinite supply of resources, then organisms would reproduce and grow in exponential numbers, without needing to struggle to survive. In this case, there would be no natural selection. In other words, without any competition for survival, there is no mechanism for variations to be selected for or against.

Which of the following terms represents a most recent common ancestor on a phylogenetic tree

node When reading a phylogenetic tree, it is helpful to understand its parts first. The beginning of the tree is called its root, which represents the most recent common ancestor of all the lineages. Just like a real tree, it has branches that show a relationship between antecedent and descendant. The nodes represent the most recent common ancestors of all the species located on the tips that originate from that node. The tips represent extant taxa. The purpose of the outgroup in phylogenetic analyses is to decide where to root the tree. Therefore, it is chosen to be something distantly related to the rest of the species of interest. A polytomy is an unresolved node that leads to more than two tips.

Which of the following terms best describes the process of natural selection?

non random Natural selection is the gradual, non-random process where alleles become more or less common as a result of the individual's interactions with the environment. While the genetic variations that lead to different traits in organisms are random, natural selection itself is a non-random process.

Which of the following is NOT a requirement for Hardy-Weinberg equilibrium? A. Large populations B. No mutation C. No migration D. Non-random mating E. No natural selection Check Answer

non random mating In order to determine whether a population is in Hardy-Weinberg equilibrium, we need to see if the Hardy-Weinberg conditions are met. To remember the requirements for Hardy-Weinberg equilibrium (ie. that a population is in Hardy-Weinberg equilibrium), use the mnemonic "Large Random M&M." Large populations Random mating No Mutation No Natural Selection No Migration:

Which of the following is NOT a type of natural selection? A. Disruptive B. Stabilizing C. Directional D. Operant Check Answer

operant

Which term describes breeding between individuals with no distinct family ties?

outbreeding Outbreeding: breeding with individuals with no distinct family ties. Inbreeding: breeding with relatives.

Suppose that the green color in peas is dominant, and the yellow color is recessive. What variable of the Hardy-Weinberg formula represents the frequency of the dominant allele (G)?

p According to the Hardy-Weinberg formula: p = frequency of the dominant allele (G) q = frequency of the recessive allele (g) p2 = frequency of homozygous dominant (GG) 2pq = frequency of heterozygous (Gg) q2 = frequency of homozygous recessive (gg)

Which Hardy-Weinberg equation implies that the frequency of all alleles of the same gene should add up to 100%? A. p + q = 1 B. p2 + 2pq + q2 = 1 Check Answer

p + q =1 The first Hardy-Weinberg equation says that p + q = 1, which implies that all alleles of the same gene should add up to 100% (if you take all the dominant alleles and add them to all the recessive alleles, we've considered 100% of the alleles in the population). The second equation says that p2 + 2pq + q2 = 1, which means that all individuals should add up to 100%. This variant of the formula looks at the different genotypes that any given individual could be, and in total all the variations add up to 100%.

Suppose that the green color in peas is dominant, and the yellow color is recessive. What variable(s) of the Hardy-Weinberg formula represent the frequency of individuals with the dominant phenotype (green)? A. p B. p2 C. p + 2pq D. p2 + 2pq Check Answer

p^2 + 2pq Two genotypes will result in the dominant phenotype: GG and Gg will result in green peas. Therefore, we have to account for both the homozygous dominant and heterozygous individuals. According to the Hardy-Weinberg formula: p = frequency of the dominant allele (G) q = frequency of the recessive allele (g) p2 = frequency of homozygous dominant (GG) 2pq = frequency of heterozygous (Gg) q2 = frequency of homozygous recessive (gg) Note: The '2' in 2pq is because an individual could be pq or qp.

Which of the following describes when two related species diverge off from a common ancestor but they both went through similar changes?

parallel Parallel evolution is when two related species diverge off from a common ancestor but they both went through similar changes

What term refers to the idea "the simpler, the better"?

parsimony The idea of parsimony is very important in evolutionary biology. Parsimony refers to the idea 'the simpler, the better'. The tree with the least number of evolutionary reversals, convergent evolution, and parallel evolution is the most parsimonious - or the simplest. This is generally how biologists formulate phylogenetic trees.

What term describes the process through which fleshy living organisms turn into solid rocks?

petrification The process of petrification describes how fleshy living organisms turn into solid rocks. As the body of a living organism becomes buried under layers of sediments, minerals slowly seep into its body and replaces organic materials, hardening the corpse.

Polyploidy is especially common in which of the following organisms? A. Animals B. Plants C. Fungi D. Protists Check Answer

plants multiple alleles for each gene Some plants are polyploid, meaning that they actually have multiple alleles (three or more) for each gene. This introduces more variety and preserves more alleles in the genome, which can come in handy for plants since a certain allele may be more useful if the environment changes

Which of the following statements does NOT accurately describe the Malthusian Theory of Population Growth? A. Unchecked population growth results in Malthusian catastrophe. B. Food production and resource growth is arithmetic. C. If the population outgrows available resources, many will die of starvation. D. Population growth is linear. Check Answer

population growth is linear. In the Malthusian Theory of Population Growth, it is postulated that population growth is exponential, while food production and resource growth is arithmetic. Therefore, unchecked population growth would eventually cause the population to outgrow the available resources and result in a Malthusian catastrophe, where many members of the population die of starvation.

What type of isolation prevents fertilization, even if mating is attempted?

prezygotic Nature secures reproductive isolation for each species through two ways: prezygotic and postzygotic isolating mechanisms. As its name suggests, prezygotic isolation prevents fertilization even if mating is attempted, hence preventing the formation of a zygote.

Which theory is more supported by fossil evidence?

puncuated equillibrium Punctuated equilibrium: This theory says that there are short spurts of evolutionary changes during long periods of stasis (no evolution). This theory is more supported by the fossil evidence.

Suppose that the green color in peas is dominant, and the yellow color is recessive. What variable of the Hardy-Weinberg formula represents the homozygous recessive (gg) frequency?

q^2 According to the Hardy-Weinberg formula: p = frequency of the dominant allele (G) q = frequency of the recessive allele (g) p2 = frequency of homozygous dominant (GG) 2pq = frequency of heterozygous (Gg) q2 = frequency of homozygous recessive (gg)

Which of the following is NOT a factor that causes microevolution? A. Genetic drift B. Mutations C. Gene flow D. Random mating E. Natural selection Check Answer

random mating Factors that Cause Microevolution: Genetic drift Non-random mating Mutations Natural selection Gene flow Note how these are opposites of the conditions for Hardy-Weinberg equilibrium, because now we are thinking about factors that cause changes to allele frequencies in a population.

How often do we encounter the conditions required for Hardy-Weinberg equilibrium in the real world?

rarely The conditions for Hardy-Weinberg equilibrium are actually rarely (if ever) met in the real world. This means that allele frequencies do change from generation to generation, and that evolution will naturally occur.

What is the first step of speciation?

reproductive isolation The first and most important step of speciation is always reproductive isolation, which leads to the interruption of gene flow between populations of the same species. Alleles cannot cross between the populations; there must be a separation. As the separation continues, the two populations gradually develop into two different species with different genes.

Which of the following accurately describes phyletic gradualism?

says that evolution occured gradually with the accumulation of many small intermediate changes The two main theories of macroevolution: Phyletic gradualism Punctuated equilibrium Phyletic gradualism: This theory says that evolution happened gradually with the accumulation of many small intermediate changes. But when we look at fossils, we cannot see those intermediary stages, hence this theory is not likely to be true.

Non-random mating within a population is a consequence of what type of selection?

sexual Non-random mating is when individuals choose who they want to mate with. This is a consequence of sexual selection. When certain traits are favored over others, they get passed onto offspring and become more represented within the allele frequencies of future generations.

Which of the following is NOT a potential cause of sympatric speciation? A. Sexual selection B. Polyploidy C. Balanced polymorphism D. Hybridization Check Answer

sexual selection There are three main ways to achieve sympatric speciation: Balanced polymorphism Polyploidy Hybridization