Biology-Chapter 13-Evolution

What was Darwin's phrase for evolution? What does it mean?

"Descent with modification" Meaning as time goes on populations modify to fit the environment they are in.

Males 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

What is homology? And how does it relate to molecular biology?

Homology is a similarity of characteristics that result from common ancestry. Molecular biology is a hereditary background documented in DNA. Species with homologous genes and sequences closely match-> common ancestor.

Why can't individuals evolve?

Individual organisms don't evolve. Populations evolve. Because individuals in a population vary, some in the population are better able to survive and reproduce given a particular set of environmental conditions.

What is the ultimate source of genetic variation? What is the source of most genetic variation in a population that reproduces sexually?

Mutation is the ultimate source for genetic variation that serves as raw material for evolution. In multicellular organisms, only mutations in cells that produce gametes can be passed to offspring and affect a population's genetic variability. Mutation; unique combinations of alleles resulting from sexual reproduction.

Be able to determine what type of selection is acting on a particular population.

Natural Selection - The selection done by nature to select individuals with the best genes for survival. Artificial selection - humans decide what individuals are best for the environment. Stabilizing selection - favors intermediate phenotypes and reduces variation Directional selection - Selects phenotypes in a specific direction on the phenotypic range. Disruptive selection - The environmental conditions favor individuals at both ends of the phenotypic range. This can lead to contrasting phenotypes in the same population.

Compare artificial selection and natural selection

Natural Selection is a population that consists of varied individuals (some variants leave more offspring) Artificial selection is man-made. For example, when people mix a golden retriever with a poodle they make a new type of dog, but they didn't evolve that way, someone made them to be that way.

Why do we say natural selection cannot produce the perfect organism?

Natural selection cannot produce the perfect organism because natural selection proves what's best suited for the environment, so that species can thrive.

Why would natural selection tend to reduce genetic variation more in populations of haploid organisms than in populations with diploid organisms?

Natural selection favors only the fittest variants from the phenotypes that are available, which may not be the ideal traits. New, advantageous alleles do not arise on demand.

Why is natural selection considered to be the main mechanism of adaptive evolution. Why not genetic drift, gene flow or mutation.

Natural selection is the main mechanism of adaptive evolution since it is consistent and repeatable. Genetic drift, gene flow, and mutation are chance events and entirely unpredictable.

How is survival of the fittest different from relative fitness.

Survival of the fittest is different from relative fitness is a. Contribution an individual makes to the gene pool, "fittest individuals" produce most viable fertile offspring pass on most genos. b. Survival of the fittest is the people with the best genes survive

What is the bottleneck effect? How has man amplified it?

The bottleneck effect is an event that leaves a small surviving population. Unlikely to have the same genetic makeup as original population.

How 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

Explain 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.