Darwin and Natural Selection
Adaptations and Evidence of Evolution
Types of Selection
Populations and Speciation
100
Why was Charles Darwin's explanation of natural selection more powerful and useful than explanations in the past?
He proposed the first evidence based explanation for natural selection.
100
What is the name for a trait or adaptation that helps an organism survive its habitat?
Adaptation
100
In this type of selection, individuals at one end of a bell-shaped curve are favored over individuals at the middle or other end. What kind of selection would this be?
Directional selection
100
Describe the founder effect?
When a few members of a population migrate and form a new population with different allele frequencies.
200
What is fitness as it relates to natural selection?
An organism's ability to survive and reproduce.
200
Why are bones useful in studying evolution of organisms?
They shows that ancient organisms have similar structures to modern ones and that modern organisms evolved from ancient ones.
200
In wolves, a medium size is preferred. Too small and the wolf can't defend itself. Too big and it can't sneak up on prey. What kind of selection would this be an example of?
Stabilizing selection.
200
This is when two populations stop interbreeding, causing genetic changes to no longer spread between the populations.
Reproductive isolation.
300
What conditions are required for natural selection to occur?
More individuals are born than can survive and fitness varies among individuals. Only those with adaptations that allow them to reproduce are "fit" and pass on their genes.
300
What is the difference between analogous and vestigial structures?
Analogous structures are two that have a similar function but not common ancestry or structure. Vestigial structures are derived from an ancestor but have lost most of their original structure or function.
300
How does natural selection affect single gene traits?
One trait causes an organism to be more fit and will increase in the population. The other trait will decrease.
300
This form of isolation is when two populations reproduce at different times and so stop interbreeding.
Temporal isolation
400
How does natural selection affect alleles?
Natural selection acts on phenotypes, causing some alleles to increase as the organisms with advantageous phenotypes survive and other alleles to decrease for phenotypes that aren't advantageous.
400
What is the name for the more recent sign of evidence that shows support for evolution using similarities between genetic codes and genes?
Molecular biology
400
What is Hard-Weinberg Equilibrium?
A condition in which allele frequencies remain constant unless factors like nonrandom mating or small population size are present.
400
The finch first arrived on the Galapagos island when a few birds migrated there from the mainland. Due to the ocean, interbreeding never occurred between the mainland population and the island population. What kind of isolation is this?
Geographic isolation.
500
Why are variable traits important in natural selection?
Without variation, one environmental change could wipe out an entire population.
500
The image shows the evolution of human skulls. The presence of orbital sockets (eye holes) is an indication of what kind of structure? (Homologous, analogous, vestigial)
Homologous
500
Describe a situation that could cause disruptive selection.
Answers vary.
500
Two orchids have different periods in which they are capable of flowering and reproducing. This would be an example of what kind of isolation?
Temporal isolation