BIOL 1409 FLASHCARDS (Chapter 13: How Populations Evolve)

BIOL 1409 CHP 13 - EVOLTUION Flashcards covering Chapter 13: How Populations Evolve. DARWIN THEORY OF EVOLUTION, EVOLUTION OF POPULATIONS AND MECHANISMS OF EVOLUTION.

What title did Charles Darwin give to his book that launched the era of evolutionary biology?

On the Origin of Species by Means of Natural Selection (commonly referred to as The Origin of Species).

What term did Charles Darwin use to describe his theory of evolution, and what does it mean?

Descent with modification; it explains that all of life is connected by common ancestry and that descendants accumulated adaptations to changing environments over time.

How does a scientific theory differ from a hypothesis according to the text?

A scientific theory is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence.

What three primary functions do fossils serve in documenting evolution?

They are the imprints or remains of organisms that lived in the past, document differences between past and present organisms, and reveal that many species have become extinct.

Based on the diagram showing transitional cetacean fossils, which early terrestrial ancestor possessed a distinctive ankle bone linking whales to cloven-hoofed mammals?

Pakicetus (and Rodhocetus).

What is homology in the context of evolutionary biology?

Similarity resulting from common ancestry.

What anatomical forelimb bones are shown as homologous structures across humans, cats, whales, and bats in the provided diagram?

The humerus, radius, ulna, carpals, metacarpals, and phalanges.

What are vestigial structures?

Remnants of features that served important functions in an organism's ancestors.

What two embryonic features are shared by both chick and human embryos as structural homologies?

Pharyngeal pouches and a post-anal tail.

According to the provided evolutionary tree diagram, are crocodiles more closely related to lizards or to birds?

Crocodiles are more closely related to birds because they share a more recent common ancestor with birds (branch point 5) than with lizards (branch point 4).

What ancestor bird species gave rise to domesticated pigeon breeds like the Fantail, Frillback, Old Dutch Capuchine, and Trumpeter through artificial selection?

Rock pigeon.

What are the two key observations and two resulting inferences of Darwin's concept of natural selection?

Observations: Heritable variations in individuals and overproduction of offspring. Inferences: Individuals well suited to the environment tend to leave more offspring, and over time, favorable traits accumulate in the population.

Why is it incorrect to state that individual organisms evolve?

Natural selection occurs through interactions between individual organisms and the environment, but individuals do not evolve; it is the population (the group of organisms) that evolves over time.

In what sense is natural selection more of an editing process than a creative process?

Natural selection does not create new alleles or traits on demand; it only screens or edits pre-existing heritable variations present in the population.

What is the ultimate (original) source of all genetic variation?

Mutations.

What three random components of sexual reproduction generate fresh assortments of existing alleles each generation?

Crossing over, independent orientation of homologous chromosomes at metaphase I of meiosis, and random fertilization.

How is a population defined in biological terms?

A group of individuals of the same species that live in the same area and interbreed.

What is microevolution?

A change in the frequencies of alleles in a population's gene pool, representing evolution occurring on its smallest scale.

What five conditions are required for a population to remain in Hardy-Weinberg equilibrium?

The population must be large, mating must be random, and there must be no mutation, no gene flow, and no natural selection.

In the Hardy-Weinberg formulas shown in the figure, what do $p^2$, $2pq$, and $q^2$ represent in terms of genotype frequencies?

$p^2$ represents dominant homozygotes, $2pq$ represents heterozygotes, and $q^2$ represents recessive homozygotes.

In an imaginary iguana population of $500$ individuals where $320$ are $WW$, $160$ are $Ww$, and $20$ are $ww$, what are the frequencies of allele $W$ and allele $w$?

The frequency of allele $W$ is $0.8$ (\n\frac{800}{1{,}000}$n) and the frequency of allele w$is$0.2$($ \frac{200}{1{,}000}$n).

What inherited inability to break down the amino acid phenylalanine affects about $1$ out of $10{,}000$ babies born in the United States?

Phenylketonuria (PKU).

What are the three main causes of microevolutionary change?

Natural selection, genetic drift, and gene flow.

What is the bottleneck effect as illustrated in the provided image, and what is its consequence?

A bottlenecking event is a drastic reduction in population size that leads to a surviving population with a severe loss of genetic diversity.

What is the founder effect?

Genetic drift that occurs when a few individuals colonize an island or other new habitat.

How is relative fitness defined?

The contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals.

What type of natural selection favors intermediate phenotypes in a population?

Stabilizing selection.

Which mode of natural selection shifts the overall makeup of the population by acting against individuals at one extreme, such as favoring larger body size in cliff swallows during cold weather?

Directional selection.

What type of selection favors individuals at both ends of a phenotypic range over individuals with intermediate phenotypes, such as beak width in African black-bellied finches?

Disruptive selection.

What is the difference between intrasexual selection and intersexual selection?

In intrasexual selection, individuals compete directly with members of the same sex for mates. In intersexual selection (mate choice), individuals of one sex (usually females) are choosy in selecting their mates.

According to 2013 CDC estimates, how many people in the United States are infected by drug-resistant microorganisms each year, and how many die as a result?

Drug-resistant microorganisms infect more than $2\text{ million}$ people and cause $23{,}000\text{ deaths}$ each year in the United States.

What three human practices contribute to the evolution of antibiotic resistance in bacteria?

Overprescribing antibiotics by doctors, premature stopping of antibiotic courses by patients, and the addition of antibiotics to animal feed by livestock producers.

What is heterozygote advantage, and how does it maintain the sickle-cell allele in geographic areas shown on the map?

Heterozygote advantage is a type of balancing selection where heterozygous individuals have greater reproductive success than either homozygote; in areas with high incidence of malaria, heterozygous individuals for the sickle-cell allele are protected from malaria without suffering severe sickle-cell disease.