Chapter 21: The Evidence for Evolution

Developmental patterns seen in a group of organisms often reveal evolutionary relationships. Place the developmental descriptions in the order that they would occur in a group of related organisms, beginning with the earliest description at the top.

1. Greatest similarity is present 2. different characteristics are lost 3. Final form is attained

Why is it that some organisms do not appear to be perfectly adapted to their environment?

Because natural selection can only work on the variation present in a population.

Which of the following are common misconceptions about evolution?

Complex organs cannot be explained by evolution, but can be explained by intelligent design. Evolution has not been demonstrated.

How does artificial selection contradict the claim that selection can only produce minor evolutionary change?

Differences between breeds can be larger than differences between different genera of animals or plants.

Which of the following statements about marsupials in Australia is true?

For many types of placental mammals found throughout the world, there is a strikingly similar marsupial mammal in Australia.

Which of the following best distinguishes vestigial from homologous structures?

Homologous structures are functional, while vestigial structures have no function.

Homology

Human coccyx

How did Peter and Rosemary Grant show that the beak size of finches on Daphne Major is affected by natural selection?

In dry years, fewer small seeds were produced on the island and the average beak size of finches increased.

Which of the following provide evidence that natural selection occurs in peppered moths?

Light moths become more abundant than melanic forms when clean air legislation is implemented. Melanie moths become more abundant than light forms in polluted areas.

Why are giraffe necks not perfectly suited for their function?

Like all mammals, giraffes only have 7 vertebrae in their necks which limits their flexibility.

Which of the following are reasons why the fossil record is incomplete?

Organisms decay or are scavenged before forming fossils. Fossils can be destroyed before they are collected. Many fossils occur in rocks that are inaccessible.

Species on islands often show great diversification; why?

The absence of many plants and animals means there are many unexploited niches

The primary difference between natural and artificial selection is

how the parents are chosen (by humans or because of their reproductive success)

arieties of which of the following organisms are the result of artificial selection?

cats pigeons dogs corn

Pseudogenes

code for traits no longer present in the phenotype of a species

The ant-eaters in South America and the Australian echidna have similar snouts and tongues that they use to capture ants. This is an example of -------- evolution

convergent

Many fishes that inhabit the sub-freezing Arctic and Antarctic waters posses antifreeze proteins; we now know that there are at least five different kinds of antifreeze protein genes that have evolved independently in different species to perform the same function. This is an example of:

convergent evolution

J. W. Tutt proposed that------colored peppered moths were more visible to predators on trees without lichens.

light or lighter

In a classic experiment, scientists selected for fruit flies with many bristles on their abdomen by

picking out and breeding the 20% of the population that had the greatest number of bristles.

Economically important organisms that have been modified significantly through artificial selection include

pigs corn cattle

As a result of convergent evolution, many marsupial mammals of Australia look similar to --------mammals found elsewhere and occupy a similar ecological niche.

placental

warbler finches

small narrow beaks

The forelimbs of vertebrates are an example of ------- structures, while the human appendix is an example of a ------ structure

Blank 1: homologous Blank 2: vestigial

The Grants were able to show that after dry years, when ----- seeds are produced, and smaller seeds are quickly eaten, the average beak depth of medium ground finches ---------

Blank 1: less, fewer, or few Blank 2: increased, grew, increases, grows, or increase

The feet of modern horses have ----- toe(s); in contrast, early horses had ------ toe(s) on their front feet and ---- toe(s) on their hind feet.

Blank 1: one, 1, a single, or single Blank 2: four or 4 Blank 3: three or 3

Fossils that contain characteristics of two separate groups of organisms are called---- fossils

Blank 1: transitional or intermediate

Typically, how are species on islands related to species on a nearby continent?

More closely

How has rock and fossil dating changed since Darwin's times?

Relative dating was used in the past; today we use absolute dating.

Absolute dating

Rocks are dated based on changes in their isotopic composition

Which are correct about pseudogenes?

They are also known as fossil genes. They are made inactive by mutation.

Which of the following is true about transitional fossils (choose all that apply)?

They help to fill in the gap in the fossil record between two separate groups. They illustrate how major transitions in life occurred.

Which of the following are reasons why island trees belong to plant families that typically do not have tree members (for example the sunflower family)?

Tree seeds rarely make it to isolated islands The tree niche is empty and so a flower can evolve through natural selection to be tree-like

Vestigial structures

Vertebrate forelimbs

Galapagos finches with powerful thick beaks typically eat large

seeds

According to some critics of evolution, natural selection can produce changes in a population, but it cannot cause substantial changes leading to

the formation of an entirely new species.