Crowdly

Characteristics acquired during an organism's life are not passed on through genes.

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result."

Which statement most accurately corrects the student's misconception?

Overproduction of offspring leads to a struggle for survival.

Only favorable adaptations have survival value.

Disuse of an organ may lead to its eventual disappearance.

Spontaneous mutations can result in the appearance of new traits.

As adults, certain species of whales possess baleen instead of teeth. Baleen is used to filter the whales' diet of planktonic animals from seawater. As embryos, baleen whales possess teeth, which are later replaced by baleen. The teeth of embryonic baleen whales are evidence that

baleen whales are descendants of toothed whales.

all whales are the descendants of terrestrial mammals.

ontogeny recapitulates phylogeny.

baleen whale embryos pass through a stage when they resemble adult toothed whales.

among ancient whales, baleen evolved before teeth.

When constructing a phylogenetic tree, we use an approach called parsimony. This refers to:

Constructing a tree with the base of the tree having the common ancestor of all descendants.

Constructing a tree with the most recent organisms at the tips of the tree.

Constructing a tree with the fewest number of independent genetic events to take place.

Constructing a tree with the exact number of independent genetic events to take place.

Which is INCORRECT about gene flow:

Gene flow enables popuations to be more similar to each other as they share genes.

Gene flow always leads to a healthier population.

Gene flow occurs when individuals can migrate to a geographically separate population and breed.

Gene flow may cause maladaptation if the migrant is not suited to the local conditions.

Insects with mutations that prevent flight (e.g., the "vestigial wing" mutation in fruit flies) usually can't survive long in nature. But in four of the following environments, flightlessness could be selected for. Which environment should favor the survival of fruit flies that can actually fly?

a forest full of bats that catch and eat insects while in flight

a cage in which food cannot be reached by sole use of the legs

a cage with slippery walls that insects can't climb and an electrified screen on top that electrocutes insects that touch it

an island where stiff winds blow some flying insects out to sea, only to drown

a swamp full of frogs that can see and catch flying insects better than crawling insects

A donkey and a horse mate. The resulting 'mule' is not fertile. This is an example of:

post-zygotic isolation due to gametic isolation.

post-zygotic isolation due to behavioural incompatability.

pre-zygotic isolation due to mechanical incompatablity.

post-zygotic isolation due to genetic incompatibility.

Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

Natural selection cannot account for losses, only for innovations.

by the principle of use and disuse

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

These organisms had the misfortune to experience harmful mutations, which caused the loss of these structures.