Biology: HW Scenarios

Similar forelimb anatomy in different species of mammals is an example of

Anatomical and molecular homologies

Fossils of some species of reptile are found only in West Africa and Brazil, even though these locations are currently separated by thousands of miles of Atlantic ocean

Biogeography

Most of the animals found on the island of Madagascar are found nowhere else, indicating they evolved from ancestral populations after Madagascar was isolated from other continents.

Biogeography

Resemblance of island species to nearby mainland species is an example of

Biogeography

Unique collection of marsupial mammals in Australia is an example of

Biogeography

Comparison of DNA sequences among single-called organisms suggests that eukaryotes are more closely related to archaea than to bacteria

Bioinformatics

The amino sequence of human hemoglobin is more similar to the sequence of hemoglobin from dogs than it is to the sequence from fish

Bioinformatics

Discovery of bones from many different dinosaur species is an example of

Fossil record

Remains of a 365 million year old organism named Ichthyostega include features that suggest it spent time both in water and on land, indication that it was a transitional species between fish and land-dwelling amphibians.

Fossil record

The oldest known and most primitive bird is the 150-million-year old Archaeopteryx. It remains display feathered wings, but its skeleton is otherwise similar to the two-legged dinosaurs that lived at that time.

Fossil record

Transmission forms that link whales with land-dwelling ancestors that are now extinct is an example of

Fossil record

Tristan da Cunha is a remote island in the Atlantic Ocean. In 1814, 15 people formed a colony there, one of whom carried a rare gene for blindness. The frequency of this gene is now 10 times higher on the island than on the mainland from which the settlers arrived.

Founder effect

As habitats change, populations of northern pine trees that were once separated can now exchange pollen. This exchange of genes between populations is allowing the previously isolated gene pools to mix.

Gene flow

Consider a population of birds living on an island. Suppose several individuals of the same species from a different population migrate to the island. Due to the arrival of the new birds, the allele frequencies in the original population change. What mechanism of microevolution is at work in this example?

Gene flow

Insecticide resistance among mosquitoes is spreading around the world after mutations that originate in one population are spread to other populations through matings.

Gene flow

Changes in average beak size in finches following dry or wet years is an example of

Observation of natural selection in action

Development of pesticide resistance in insects is an example of

Observation of natural selection in action

Researchers discovered that female gray tree frogs prefer to mate with males who sound the longest mating calls.

Sexual selection

Same genetic language of DNA and similar gene in yeasts, fruit flies, and humans is an example of

Anatomical and molecular homologies

A sudden volcanic eruption kills many members of a population of elk. By chance, the individuals that remain do not have the same mix of genes as the original population.

Bottleneck effect

Although millions of prairie chickens once roamed the Midwest, their numbers dwindled to only 50 individuals in the 1990's. These few individuals have since produced a larger population. The genetic variation among the current population is quite low.

Bottleneck effect

The skulls of humans and other primates have the same basic layout of bones, even though the heads are drastically different sizes and shapes

Comparative anatomy

As the descendants of a remote ancestor spread into various habitats over millions and millions of years, natural selection resulted in diverse modifications.

Evolution

In multicellular organisms, only mutations in cells that produce gametes can be passed to offspring and affect a populations genetic variability

Information flow

Plants in a wildflower population may differ in reproductive success because some attract more pollinators

Interactions within biological systems

Darwins finches differ in their feeding habits and the size and shape of their beaks, which are specialized based on what they eat

Relationship of structure to function