Chapter 22 A

Prior to the work of Lyell and Darwin, the prevailing belief was that Earth is ...

a few thousand years old, and populations are unchanging.

Darwin and Wallace made independent observations in different parts of the world. Which statements are true?

-Both collected huge numbers of specimens and realized that individuals vary within species. -Both witnessed nature up close and realized it was a battlefield with massive casualties. -Both observed slightly different species on nearby islands and concluded that species could change over time.

In the mid-1900s, the Soviet geneticist Lysenko believed that this winter wheat plants, exposed to increasingly colder temperatures, would eventually give rise to more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of ...

Lamarck

Which of the following statements about Lamarck is accurate?

Lamarck thought evolution had occurred.

What did Wallace conclude from observing that the bones in manatee flippers look similar to the bones in a human arm and hand?

Manatees' arm and finger bones are evidence that manatees share a common ancestor with land mammals.

When Charles Darwin set sail on the HMS Beagle, what did he and most of his contemporary scientists think about the origin of species?

Most scientists, including Darwin, thought each species was specially created by God in its present form and did not change over time.

Charles Darwin ...

proposed natural selection as the mechanism of evolution.

Began the convention of naming species with two names (a binomial): a genus and species epithet.

Carolus Linneaus

Discovered that the deeper fossils were found in layers of rock, the more they differed from current species. To explain these differences he proposed that periodic sudden calamitous events must have destroyed the older versions of species

Georges Cuvier

As Wallace traveled the Malay Archipelago, he noticed that western islands had placental mammals, like monkeys. Eastern islands had marsupial mammals, like Kangaroos. How did Wallace explain this distribution?

The western islands were once connected to Asia and the eastern islands had been connected to Australia. The islands had never been connected to each other.

When Cuvier considered the fossils found in the vicinity of Paris, he concluded that the extinction of species ...

occurs, but that there is no evolution.

After his journey on the HMS Beagle, Darwin made this now-famous sketch in his notebook. Which ideas does it represent?

-All species are connected to one another in a "family tree" -Species descend from other species just as naturally as children come from parents. -All species are linked to one another by common ancestry.

Which of the following statements apply to the variation in human skin color?

-Human skin color variation is primarily determined by the type and amount of melanin pigment in the skin. -Human skin color variation likely evolved in response to differences in the intensity of sunlight around the world. -Human skin color variation evolved recently in hominid evolution, once some populations of our human ancestors migrated out of Africa.

Which observations led Darwin to establish a relationship between extinct and living animals?

-The fossilized remains of giant sloths were found in places where smaller sloths now live. -The bony shells of armadillos resembled the shells of ancient Glyptodon fossils.

An adaptions is ...

a trait that gives an organism a reproductive advantage in the current environment.

Darker skin is more prevalent in high-UV areas. Dr. Nina Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis?

the melanin in darkly pigmented skin protects circulating folate from being destroyed by UV radiation, and folate is important in human reproduction

In what way does natural selection depend on the specific environment in which an organism lives?

when the environment changes, traits that were beneficial to an organism may become harmful and vice versa.

Darwin and Wallace independently arrived at the same conclusion that species change over time. Which observations supported their conclusions?

-The fossilized remains of giant sloths were similar to the smaller, living sloths Darwin encountered. -Tortoises from different Galapagos islands have distinct shells. -Bird families clustered geographically: cockatoos in the Malay Archipelago and Australia, macaws and hummingbirds in the Americas. -The bony shells of armadillos resembled fossilized shells from the extinct Glyptodon. -Mockingbirds from different Galapagos islands had subtle, consistent differences. -Birdwing butterflies were found throughout the Malay archipelago, but species differed slightly from island to island.

Proposed a nested hierarchical scheme for classifying organisms that is still used today.

Carolus Linneaus

Proposed that new species arise very slowly over time when individuals that are born with favorable traits leave more offspring, resulting in an increase in the favorable traits in the population.

Charles Darwin

Proposed that the same geologic processes are operating today as in the past, and at the same slow, steady rate.

Charles Lyell

Proposed that new species arise when individual organisms change during their life time to improve their traits, and these changes are inherited by their offspring.

Jean-Baptiste de Lamarck

Which of the following statements accurately describes melanin's function?

Lighter skin has less of the dark-brown eumelanin that protects cells from UV damage.

Based on the risk factors discussed in the video, which of the following groups would be most likely to develop the bone disease rickets?

children born to parents with dark skin living far from the equator

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it ...

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

Human populations in low-UV environments tend to have more lightly pigmented skin. One explanation is that the selective pressure for dark skin decreases as UV intensity decreases. At the same time there is selection for lighter skin to absorb more UV radiation, which is needed for vitamin D production. What evidence supports the vitamin D hypothesis for the evolution of lighter skin tones?

indigenous peoples living at high latitudes have darker skin, but they eat foods rich in vitamin D

Catastrophism, the regular occurrence of geological or meteorological disturbances (catastrophes) as a cause of geological change and extinction of species, was Cuvier's attempt to explain the existence of ...

the fossil record.