Pre: temporal isolation
The salamanders Ambystone tigrinum and A. maculatum breed in the same areas. A. trigrinum mates from late February through March. A. maculatum does not start mating until late March or early April.q
Post: hybrid breakdown
Two species of mice are mated in the lab and produce fertile hybrid offspring, but offspring of the hybrids are sterile.
Post: hybrid sterility
When fruit flies of two particular species are crossed in the lab, their offspring are unable to produce eggs and sperm.
Pre: mechanical isolation
A zoologist observed two land snails of different species that were trying to mate with little success because they apparently did not "fit" each other.
Pre: behavioral isolation
Male fiddler crabs wave their large claws to attract the attention of females. Each species has a slightly different wave.
Pre: gamete isolation
When different species of tobacco plants are crossed in a greenhouse, the pollen tube usually bursts before the eggs are fertilized.
Pre: habitat isolation
Blackjack oak grows in dry woodlands, and scrub oak grows in dry, rocky, open areas. Pollen of one species seldom pollinates the other.
Post: hybrid inviability
The tiglon offspring of a lion and a tiger are often weak and unhealthy.
What category of "evidence for evolution" does the following belong? Marsupials in Australia, such as kangaroos and koalas, diversified in isolation on that island continent after it became separated from the landmasses on which placental mammals diversified.
What category of "evidence for evolution" does the following belong? The wing bones of a bat resemble the bones of a cow's foreleg.
If an earthquake hit a small island so that all but a tiny group of lizards were eliminated and the survivors spread out over the island, this would be an instance of?
The original source of all genetic variation is
Descent with Modification
Darwin's name for the process in which descendants of the earliest organism accumulated different adaptation as they spread into various habitats over millions of years.
The change in the relative frequencies of alleles in a population over several generations.
The gain or loss of alleles from a population by the movement of individuals or gametes into or out of the population.
This type of trait improves an organism's ability to survive and reproduce in a particular environment.
Rabbits living farther north tend to have smaller ears. This is an example of?
The smallest unit that can evolve.
Under some conditions, heterozygotes have greater reproductive success than homozygotes. What is this called?
Fertilized eggs of earthworms, insects, and snails all go through the same pattern of divisions.
The genes of humans and chimpanzees are about 99% identical.
Remains of upright-walking but small-brained apes have been found in Africa.
All animals with backbones have 12 pairs of nerves extending from the brain.
A protein call albumin is very similar in dogs and wolves, less similar in dogs and cats.
The farther an island is from the mainland, the more different its plants and animals are from those on the mainland.
Animals called trilobites were common in the oceans 300 million years ago but they have been extinct for millions of years.