Chapter 21 - Evidence for Evolution

Horses are members of an animal family that produced many extinct species and originated approximately _______________ million years ago.

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All modern members of the horse family are large, ___________________ -legged, ____________________ -running animals adapted to living in open _______________________.

All modern members of the horse family are large, longer -legged, faster -running animals adapted to living in open grasslands.

Frequencies of alleles from generation to generation are known as __________________ _________________________.

Allele Frequency

The medium ground finch of the Galápagos islands feeds on small seeds, produced in abundance during _______________________ years.

Answer: wet, rainy or wetter

What type of evidence for evolution is provided by fossils?

Direct

How have scientists imposed selection on Drosophilia melanogaster (fruit fly)?

Drosophilia melanogaster originally had 9.5 bristles on their abdomen. Scientists chose only the flies with the most bristles on their abdomen to reproduce. After 86 generations, the average number of bristles quadrupled to nearly 40.

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.

What are pseudogenes?

Fossil genes/ traces of previously functioning genes (now muted).

Which of the following is the most direct evidence for evolution?

Fossils

What are the five agents of evolutionary change?

1. Mutation 2. Gene Flow 3. Nonrandom Mating 4. Genetic drift 5. Selection

What makes populations vary form the Hardy-Weinberg predictions?

1. Natural selection favoring homozygotes over heterozygotes 2. individuals choosing to mate with genetically similar individuals. 3. Influs of individuals from other populations. 4. Mutations occuring.

Hardy-Weinberg equilibrium states that proportions of genotypes do not change in a population. What conditions must be met for this to be true?

1. No mutations take place. 2. No gene transfer to or from other sources. (no immigration or emmigration) 3. Mating is random. 4. The population size is very large. 5. No selection occurs

What are the three conditions for natural selection?

1. Phenotypic variation must exist. 2. This variation must lead to differences among individuals. 3. This variation must be gene based. It must be transmissible to the next generation.

Scientists use Potassium dating to date fossils that are _________________ or older.

1.25 billion years old

Regarding the peppered moth, many studies have shown that in polluted areas, the ____________________ form of the moth is favored by natural selection, and in unpolluted areas, the ______________________ form of the moth is favored.

dark (melanic) and light (peppered)

Organisms that share a common ancestor often show similarities in their early __________________ development before diverging into varied forms.

embryonic

In all cases when scientists have performed artificial selection experiments on fruit flies, a strong and predictable ________________________ response has been observed.

evolutionary

Contrary to the claims by supporters of intelligent design, the fossil record shows that many complex features of species such as the bones in the mammalian ear have ____________________.

evolved incrementally

Organisms that are transitional between hoofed mammals and whales, between reptiles and mammals, between apes and humans, and between fish and tetrapods are all examples of _____________ that have been discovered.

fossil intermediates

What does the Hardy-Weinberg principle predict?

genotype frequencies

In the laboratory setting, selection for a trait in fruit flies ___________________________.

has consistently lead to a strong, predictable evolutionary response

Even though they serve different functions, the forelimb of a frog and the forelimb of a bat share structural similarities and are derived from a common ancestor. This makes these forelimbs an example of ____________________.

homologous structures

The primary difference between natural and artificial selection is ___________________.

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

The fossil record reveals that during the last 25 million years most of the lineages in the horse family have exhibited a rapid and substantial ________________ in size.

increase

Even though there are gaps in the fossil record, some of the most direct evidence for evolution comes from _______________ fossils that illustrate how certain major transformations in life forms occurred.

intermediate

Modern members of the horse family have teeth that are _________________.

large with a complex pattern of ridges

The observation that the relative frequencies of melanic to light peppered moths changes with the color of tree bark provides support for _________________.

natural selection

Which of the following are anatomical features that provide evidence for evolution?

o Early embryonic similarities o Vestigial structures o Homologous structures

What evolutionary transitions that are documented by the fossil record.

o Fish and tetrapods o Hoofed mammals and whales o Dinosaurs and birds

What is documented by the fossil record.

o Levels of biodiversity through time o Major mass extinctions in the past o Successive evolutionary change

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

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

What are typical characteristics of all modern members of the horse family?

o Long legs o Adapted to grasslands o Fast runners

What are characteristics of absolute dating of rocks

o Rocks are dated based on changes in their isotopic composition o Dating is more accurate

What are characteristics of relative dating of rocks

o Rocks are dated based on their position. o Dating is less accurate

Which of the following is true about transitional fossils?

o They help to fill in the gap in the fossil record between two separate groups. o 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)?

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

1. Supporters of intelligent design cannot explain the presence of ______________.

o vestigial structures o imperfect adaptations

When considering that Earth is a(n) ___________________ system, it is easy to see that evolutionary theory does not violate the second law of thermodynamics.

open

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

placental

In 1896, J. W. Tutt proposed that light colored peppered moths were more visible to predators on ____________________.

sooty trees that have lost their lichens due to pollution

Island species are usually most closely related to __________________.

species on nearby continents

The criticism that evolution violates the second law of thermodynamics and that life should become more disorganized not more organized is not taking into account that energy constantly enters the biosphere from ______________________.

the Sun

Variations in the beak shape and size of Galapagos finches can be related to _______________________________. their feeding habits.

their feeding habits.

Scientists use Carbon dating to date fossils that are _________________.

up to approximately 5,700 years old

Prior to 1850, the melanic form of the peppered moth in Europe was ____________________.

very rare

A ____________________ structure has no apparent function in a species, but is fully functional in the species' ancestors.

vestigial

Two types of structures in adult organisms that provide anatomical evidence for evolution are _____________________ and ___________________________ structures.

vestigial and homologous

Some species have anatomical features that have no apparent function but resemble structures of their presumed ancestors; these anatomical features are called _________________.

vestigial structures

In ______________________ selection, humans choose the parents of the next generation, while in ________________________ selection, organisms that survive and reproduce are those that pass their genes on.

In artificial selection, humans choose the parents of the next generation, while in natural selection, organisms that survive and reproduce are those that pass their genes on.

The phenomenon, where dark forms of moths become more prevalent than light forms in industrialized areas, is known as ___________________ ____________________.

Industrial melanism

Which of the following statements about the horse family is true?

It originated 55 million years ago and over that time many of its members have become extinct.

Peter and Rosemary Grant studied _________________ on the island of ____________________.

Peter and Rosemary Grant studied medium ground finches on the island of Daphne Major.

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

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

What is convergent evolution?

Similar forms of different organisms evolved because of similar selective environmental pressures.

What is the preferred food of the Galápagos medium ground finch?

Small, tender seeds

How has the fossil record changed since Darwin's time?

Today the fossil record is far more complete.

The odd proportions of dachshunds have resulted from _____________________.

artificial selection for dogs that could enter narrow badger holes

The similar shapes of fast swimming marine predators are an example of ________________ evolution.

convergent

When two species from different lineages independently evolve similar characteristics because they occupy similar environments, we observe _____________________.

convergent evolution

The flying squirrel is a North American mammal, and the sugar glider is an Australian marsupial. Both of these animals look very similar despite being different species. The phenotypic similarities in these animals can be explained by _________________________.

convergent evolution.

What are the 3 ways artificial selection can occur?

1. Experimentally (fruit flies and abdomen bristles 2. Agriculture (humans select plants for traits to produce more food - example corn) 3. Domestication of animals (animals are selected for certain traits and bred)

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 or formed 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.

____________________ evolution happens when two species from different lineages independently evolve similar characteristics because they occupy similar environments.

Convergent

Finches on the Galapagos islands exhibit remarkable variation in the shape of their beaks. What best explains this variation?

Differences in their feeding habits

J. W. Tutt proposed that _______________ colored peppered moths were more visible to predators on trees without lichens. In contrast, the _________________ forms were camouflaged on sooty trees without lichens.

J. W. Tutt proposed that light colored peppered moths were more visible to predators on trees without lichens. In contrast, the dark forms were camouflaged on sooty trees without lichens.

Early horses had four toes on the front feet and three toes on the hind feet, all encased in fleshy pads. What statement correctly describes how the toes have changed during the evolution of modern horses?

Modern horses have a single toe enclosed in a bony hoof.

Molecular analysis of lactase DNA ______________________ in humans shows that genes for that enzyme have ____________________ evolved in Africa and Europe to produce the same result.

Molecular analysis of lactase DNA sequences in humans shows that genes for that enzyme have independently evolved in Africa and Europe to produce the same result.

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

More closely

What makes evolution possible?

Mutation

Most evolutionary biologists would agree that the primary process responsible for evolution is _________________ _____________________.

Natural selection

What is considered by scientists to be primarily responsible for evolution?

Natural selection

Describe the adaptations that result from natural selection.

Natural selection does not always produce perfectly working adaptations, because it can only work on the genetic variation present in a population.

How does isotopic dating make dating fossils possible and accurate?

They use the half life of the element used for the dating.

Today, fossils have been found that link __________________.

all major groups of vertebrates

Most of the species that humans use as food have been modified through _______________ selection.

artificial

The experiment on the Drosophilia fruit files and its result of producing flies with quadruple the number of bristles on their abdomen is an example of __________________________.

artificial selection

The great variety of breeds of cats, dogs and other domestic animals have arisen through _________________.

artificial selection

The short legs and broad feet of early horses made them well adapted to their habitat which was ______________.

wooded areas