BIOA01 - Deck 2 - Q51~Q100

Question 1

What is mutation? Why is it important for evolution?

Answer 1

• Mutation is a change in an organism’s DNA sequence.
• Mutation introduces genetic diversity, which serves as the base for natural selection and adaptation.

Question 1

Briefly, what are some general types of mutations?

Answer 1

There are several common types of mutations, including point mutations, insertions, deletions, and chromosomal rearrangements.

Question 2

Describe the importance of Lenski’s long-term experimental evolution of E. coli.

Answer 2

Lenski’s experiment with E. coli demonstrated how bacteria could evolve new traits in response to changing environments, showcasing the power of natural selection and adaptation over time.

Question 3

What is drift (aka genetic drift)? Why is it important for evolution?

Answer 3

Genetic drift refers to the random changes in allele frequencies that occur in small populations, that can reduce genetic diversity and affect evolution.

Question 4

Why are the effects of drift most dramatic on small populations?

Answer 4

Small populations can quickly lose genetic diversity (fixation of alleles) due to random changes in allele frequencies through genetic drift.

Question 5

What is a bottleneck? What is a founder effect? How are they similar and how are they different?

Answer 5

Both bottleneck and founder effect are genetic events Bottleneck and founder effect both decrease population size and genetic diversity (causes are distinct).A bottleneck happens when a population decreases drastically, while the founder effect takes place when a small group forms a new population.

Question 6

What is gene flow (aka migration)? Why is it important for evolution?

Answer 6

Gene flow refers to the transfer of genetic material between different populations, which plays a crucial role in introducing new genetic variation and preventing excessive divergence between populations.

Question 7

How can we observe the impact of gene flow in natural populations?

Answer 7

The impact of gene flow can be observed by studying the gene frequency changes between connected populations, and greater gene flow results in increased genetic similarity.

Question 8

What is natural selection? Why is it important for evolution?

Answer 8

Natural selection is the process by which individuals with advantageous traits are more likely to survive and reproduce, leading to those traits becoming more common in a population. It’s crucial for adapting to changing environments.

Question 9

What is fitness? What is relative fitness?

Answer 9

Fitness is how well an individual is suited to survive and reproduce in their specific environment. Relative fitness compares the reproductive success of one genotype to others in the same population.

Question 10

Describe and discern between the three modes of natural selection: directional, stabilizing, and disruptive?

Answer 10

Directional selection favors one extreme phenotype, stabilizing selection favors intermediate phenotypes, and disruptive selection favors both extremes, leading to the divergence of traits.

Question 11

Describe how Darwin’s finches can provide an example of directional selection.

Answer 11

Drought causes directional selection in Darwin’s finches, favoring larger beaks and increasing their frequency as they access scarce food.

Question 12

Describe how selection of goldenrod gall flies provides an example of stabilizing selection.

Answer 12

Goldenrod gall flies display stabilizing selection as intermediate-sized larvae have the highest survival rate because extreme sizes are less suitable for their environment.

Question 13

What is nonrandom mating? What is the importance of inbreeding, assortative mating, and self-fertilization on changes in allele frequencies and on the evolution of populations?

Answer 13

Nonrandom mating is when individuals choose mates based on traits, leading to inbreeding, assortative mating, and self-fertilization affecting genetic diversity.

Question 14

What was Darwin’s puzzle with respect to traits influencing sexual reproduction?

Answer 14

Darwin was perplexed about how traits that appeared to hinder survival (such as elaborate feathers) could evolve via sexual selection.

Question 15

Why are male elephant seals so much larger than females?

Answer 15

Sexual selection has led to male elephant seals evolving to be larger in size, as larger males have better mating success.

Question 16

What is sexual dimorphism?

Answer 16

Sexual dimorphism is the term used to describe the physical differences between males and females of a species.

Question 17

What is sexual selection?

Answer 17

Sexual selection favors traits that improve mate attraction and reproduction.

Question 18

What is intrasexual competition? Give examples.

Answer 18

Intrasexual competition is when members of a sex compete for access to the opposite sex. Examples include male deer fighting for mates and male lions vying for control of a pride.

Question 19

What is intersexual competition? Give examples.

Answer 19

Intersexual competition occurs when one sex, typically females, selects mates based on particular characteristics. For instance, peahens selecting peacocks with the most ostentatious plumage.

Question 20

What is the difference between sexual selection and natural selection?

Answer 20

Sexual selection focuses on traits that increase mating success, while natural selection focuses on traits that improve survival and reproduction.

Question 21

What is meant by differential investment by males and females in the context of reproduction?

Answer 21

Male and female energy and resource investments in raising offspring differ. Females typically invest more due to pregnancy and nursing.

Question 22

What is the fundamental asymmetry of sex?

Answer 22

The fundamental asymmetry of sex is based on the fact that females in many species tend to invest more in offspring than males, leading to the development of certain mating behaviors and traits.

Question 23

What are “good genes”? How was Alison Welch’s experiments with gray tree frogs a nice demonstration of good genes in sexual selection?

Answer 23

“Good genes” refer to genes that increase offspring fitness. Alison Welch’s experiments with gray tree frogs demonstrated that females prefer males with calls indicating healthier genetic quality.

Question 24

Why do male and female grebes look very similar? What is different about them in contrast to birds of paradise or elephant seals where males and females look very different from each other?

Answer 24

Male and female grebes share parental duties, resulting in a lack of sexual dimorphism. In contrast, birds of paradise and elephant seals exhibit distinct appearances due to differing reproductive roles.

Question 25

Why do seahorses represent an example of sex role reversal? Why does role reversal validate the assumptions of sexual selection theory?

Answer 25

Seahorses represent an example of a sex role reversal because the males become pregnant and carry the developing embryos. This validates assumptions of sexual selection theory by demonstrating that the sex that invests more in reproduction becomes choosier in selecting mates.

Question 26

What is balancing selection?

Answer 26

Balancing selection is a type of natural selection that maintains genetic diversity by favoring multiple alleles in a population.

Question 27

What is a balanced polymorphism?

Answer 27

A balanced polymorphism is when two different versions of a gene (alleles) are maintained in a population because of balancing selection.

Question 28

What is heterozygote advantage?
Describe an example.

Answer 28

Heterozygote advantage is when individuals with two different alleles (heterozygous) for a particular gene have a survival or reproductive advantage over individuals with two identical alleles (homozygous)
Sickle cell anemia resistance in individuals who inherit one normal and one sickle cell allele, which provides protection against malaria.

Question 29

What is negative frequency-dependent selection? Describe an example.

Answer 29

Negative frequency-dependent selection is a concept where the fitness of a trait decreases when it becomes more common in a population.
For example, let’s say there are wolves hunting deer and bunnies. The wolves might target the bunnies because there are MORE of them, making it less advantageous to be the most common prey type.

Question 30

What is an adaptation?

Answer 30

An adaptation is a special trait or feature that helps an organism survive and thrive in its specific environment.

Question 31

What is meant by the statement that natural selection favors a competitive optimum?

Answer 31

This statement means that in evolution, natural selection favors traits that help organisms compete effectively for resources and reproduce successfully, leading to the survival of the fittest.

Question 32

Why are adaptations often compromises?

Answer 32

Adaptations are often compromises because they involve trade-offs where improving one aspect of an organism’s trait may come at the cost of another trait’s performance.

Question 33

Why do adaptations lag environmental change?

Answer 33

Adaptations lag environmental change since it takes a LOT of time for species to evolve new traits that help them better fit their changing environment.

Question 34

Why is a legless lizard not a snake?

Answer 34

A legless lizard is not a snake because it has features that snakes lack such as movable eyelids and external ear openings.

Question 35

What is the Tree of Life?

Answer 35

The Tree of Life is a diagram that shows the evolutionary relationships among different species on Earth, showing how they are all connected through common ancestry.

Question 36

Who was Carolus Linnaeus?
What is classification?
What is taxonomy?
What is Linnean taxonomy?

Answer 36

Carolus Linnaeus was a Swedish botanist. He made a system for organizing living organisms called taxonomy.
Classification is the arrangement of living things into categories based on their similarities.
Taxonomy is the science of naming, defining, and classifying living organisms.
Linnean taxonomy is Linnaeus’s system of naming and categorizing species into groups such as genus and species.

Question 37

What is a nested hierarchy?

Answer 37

It’s about how species fit within broader groups based on shared characteristics, showing their evolutionary relationships.
(Think of it like Russian nesting dolls)

Question 38

What are the taxonomic groupings laid out by Linnaeus in order from largest to smallest (with respect to inclusivity)?

Answer 38

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
(Can be memorized by the pneumonic, “Did King Philip Come Over For Grape Soda?”)

Question 39

How do we get new species?

Answer 39

New species can arise through a process called speciation, where populations of a common ancestor evolve into distinct, reproductively isolated groups.

Question 40

What is genetic isolation?

Answer 40

Genetic isolation is when different groups of organisms within a species become separated and can no longer interbreed. This leads to the development of distinct genetic differences.

Question 41

What is genetic divergence?

Answer 41

Genetic divergence is the process where populations accumulate differences in their genetic makeup over time, eventually becoming different from each other.

Question 42

How are species defined and identified?

Answer 42

Species are defined and identified using various concepts: the biological species concept (BSC), morphological species concept, ecological species concept, and phylogenetic species concept.

Question 43

Describe the biological species concept? Describe pros and cons.

Answer 43

The BSC defines a species as a group of organisms that can interbreed and produce fertile offspring.
It does not apply to asexual species or extinct species.

Question 44

What is reproductive isolation?

Answer 44

Reproductive isolation refers to the barriers that prevent members of different species from interbreeding and producing fertile offspring.

Question 45

What is prezygotic isolation?
Give examples.

Answer 45

Prezygotic isolation is when different species or populations are prevented from mating.
Examples of prezygotic reproductive isolation include;
1. Geographical
2. Ecological
3. Temporal
4. Behavioral
5. Gametic
6. Mechanical/Anatomical

Question 46

What is postzygotic isolation?
Give examples.

Answer 46

Isolating factors come into play after fertilization. Result in the failure of a fertilized egg to develop into a fertile individual:
1. Hybrid inviability
2. Hybrid sterility

Question 47

Describe the morphospecies concept?
Describe pros and cons.

Answer 47

The morphospecies concept defines species based on their physical characteristics, without considering genetic or ecological factors.
It’s simple to apply but doesn’t consider hidden genetic variations or polymorphisms within species.

Question 48

What is the ecological species concept?
Describe pros and cons.

Answer 48

The ecological species concept defines species based on their unique ecological roles and requirements.
It can be challenging to apply in cases of cryptic or closely related species.

Question 49

What is the phylogenetic species concept?
Describe pros and cons.

Answer 49

The phylogenetic species concept defines species based on their common ancestry.
Its use is limited by the difficulty of determining the appropriate scale of common ancestry.