Chapter 16 Biology

How would Lamarck have explained the length of a giraffe's neck?

1) A giraffe could have acquired a long neck because it began to stretch its neck upward to reach higher and higher on trees looking for leaves to eat. 2) As the giraffe stretched toward leaves on higher branches, its neck would grow a little longer. 3) Giraffes could then pass on their long neck to their offspring who could further lengthen their necks during their lifetimes. (*remember-> this is a false idea. The Giraffe gets its long neck due to natural selection)

Describe how you could use artificial selection to breed pigeons with large beaks

1) Find pigeons that naturally have larger than normal beaks. 2) Mate these pigeons. 3) Repeat this process over several generations until you achieve the desired beak size.

Process of natural selection

1) Individuals in a population have many variations. 2) Some offspring inherit traits that increase fitness (adaptations). 3) Adaptations are passed on to the next generation. 4) Over time, adaptations accumulate in a population. 5) The accumulation of adaptations may lead to the evolution of a new species.

Properties of Natural Selection

1) More offspring are produced than can survive to reproduce. There is competition for limited resources, or a struggle for existence. 2) Individuals exhibit variation in their traits and some of these differences can be passed on to their offspring. 3) Inherited traits that increase an organism's ability to survive and reproduce are called adaptations. 4) Differences among adaptations affect an individual's fitness—the ability to survive and reproduce in a specific environment. 5) Only the fittest organisms live to reproduce and pass on their adaptive traits to offspring. This is known as the survival of the fittest

What are the three ways a species vary, and what are some examples?

3) Over Time: Glyptodonts and armadillos

During Darwin's time, geologists were suggesting that Earth was ___________ and __________

Ancient; changed over time

Genetics and Molecular Biology

At the molecular level, the universal genetic code and homologous molecules such as genes and proteins provide evidence of common descent.

Darwin observed that the birds he would eventually discover were finches had differently shaped beaks. What might this suggest about the eating habits of the birds? Explain.

Because birds use their beaks to eat or capture food, differently shaped beaks might mean that the birds lived on different diets.

Given its body structure, which tortoise above would require a habitat where food is easy to reach?

Because the Isabela Island tortoise has a short neck that restricts the movement of its head, it would require a habitat where food is easy to reach.

Biogeography

Biogeography is the study of where organisms live now and where they and their ancestors lived in the past.

analogous structures

Body parts that share a common function, but neither structure nor common ancestry, are called analogous structures. Analogous structures do not provide any evidence for evolutionary descent. ex) Wing of a Bee and Bird, snake tongue and dog nose

Why is camouflage considered an adaptation?

Camouflage is a heritable trait that can help an organism avoid predation and thereby increases the chances of its survival.

All living cells use _____and ______ to code heritable information.

DNA and RNA

Common Ancestors

Darwin argued that all species are descended, with modification, from common ancestors. Through descent with modification, all organisms—living and extinct— are linked on a single tree of life.

Darwin's collection and conclusion

Darwin collected fossils, the preserved remains of ancient organisms. He noticed that some fossils of extinct species resembled living species. Darwin's findings led him to think that species are not fixed and that they could change by some natural process.

Darwin's theory

Darwin developed a scientific theory to explain how evolution, or change over time, occurs in living things. Darwin's theory explains how modern organisms have evolved over long periods of time through descent from common ancestors.

What important information about the Galápagos Islands tortoises did Darwin learn?

Darwin learned that the shell shape of a tortoise could be used to identify the island it inhabited. Isabela Island Tortoise- has a short neck who lives in an island with easy-to-reach food and abundant vegetation Hood Island Tortoise- has a long neck who lives in a island with little vegetation and food high-above

The Origin of Species

Darwin published On the Origin of Species in 1859. In the book, Darwin describes and provides evidence for his explanation of how evolution occurs. He called this process natural selection because of its similarities to artificial selection.

How do humans affect artificial selection? What role does nature play?

Darwin stated that nature provides the variation among organisms, and humans select and breed for the variations they find useful or appealing.

Every organism alive today _________from ancestors who survived and reproduced.

Descended

The principle that living species descend, with changes, from other species over time is referred to as ________

Descent with modification

fitness

Differences among adaptations affect an individual's fitness—the ability to survive and reproduce in a specific environment. -> Only the fittest organisms live to reproduce and pass on their adaptive traits to offspring. This is known as the survival of the fittest.

Which of the following hypotheses did the Grants test?

Differences in beak size and shape produce differences in fitness.

Darwin's Observations Aboard the HMS Beagle

During his five-year trip on the Beagle, Darwin made many observations and collected a great deal of evidence. -He noticed that many different, yet ecologically similar, animal and plant species occupied different, yet ecologically similar, habitats around the globe. -On the Galápagos Islands, Darwin noticed that the traits of many organisms—such as the shell shapes of tortoises—varied from island to island. -He noticed that different, yet related, animal and plant species occupied different habitats within a local area.

The ________ provides physical evidence of descent with modification over long periods of time

Fossil Record

Evolution

From generation to generation, populations continue to evolve as they become better adapted, or as their environment changes.

Geology

Geologists James Hutton and Charles Lyell argued that Earth is many millions of years old. They also argued that the processes changing Earth today, like volcanism and erosion, are the same ones that changed Earth in the past *Knowing that Earth could change over time helped Darwin realize that species might change as well. Knowing that Earth was very old convinced Darwin that there had been enough time for life to evolve

Homologous structures

Homologous structures are shared by related species and have been inherited from a common ancestor. Similarities and differences among homologous structures help determine how recently two groups shared a common ancestor ex) Mammalian leg and amphibian leg, bat wing and mouse arm, reptile foot and bird foot, dolphin fin and fish tail,

Vestigial structures

Homologous structures that are greatly reduced in size or have little to no function are called vestigial structures ex) Hipbones in dolphins, eyes on a blind cave fish

Which observation caused Thomas Malthus to form his theory about population growth?

Human birth rate was higher than the death rate.

James Hutton

Hutton argued that Earth is many millions of years old. Knowing that Earth was very old convinced Darwin that there had been enough time for life to evolve

Which of the following is an idea attributed to Malthus?

If the human population grew unchecked, there wouldn't be enough living space and food for everyone

Old Thought of Earth

In Darwin's day, most Europeans believed that Earth and all its life forms were only a few thousand years old and had not changed very much in that time. Several scientists who lived around the same time as Darwin began to challenge these ideas. These scientists had an important influence on the development of Darwin's theory of evolution.

Adaptations

Inherited traits that increase an organism's ability to survive and reproduce are called adaptations

Natural selection acts on ____ traits

Inherited; don't get this confused with acquired. Acquired traits are those that are acquired can be obtained, inherited traits are those that some from the parent generation.

What does the phrase struggle for existence mean?

It means that members of a population compete regularly to obtain food, living space, and other necessities of life.

Why were the similarities among rheas, ostriches, and emus surprising to Darwin?

It was surprising because these different birds lived so far away from each other.

Lamarck's Evolutionary Hypothesis

Jean-Baptiste Lamarck was one of the first scientists to propose hypotheses about how evolution occurred. To explain evolution, Lamarck hypothesized that all organisms have an inborn drive to become more complex and "perfect". ->According to Lamarck, an organism could gain or lose traits during its lifetime by using or not using certain organs. Lamarck also hypothesized that acquired characteristics could be passed on to an organism's offspring leading to evolution of the species.

In what two ways did an understanding of geology influence Darwin?

Knowing that Earth could change over time helped Darwin believe that life might change as well. Knowing that Earth was very old assured Darwin that there had been enough time for life to change.

How did Lamarck propose that species change over time?

Lamarck proposed that by selective use or nonuse of organs, organisms acquired or lost certain traits during their lifetime. These traits could then be passed on to their offspring. Over time, this process led to change in a species.

Jean-Baptiste Lamarck

Lamarck was one of the first scientists to recognize that evolution has occurred and that organisms change to live more successfully in their environment. His general ideas about evolution and adaptation influenced Darwin.

How did Lamarck pave the way for the work of later biologists?

Lamarck was one of the first to develop scientific hypotheses about evolution and to realize that organisms change over time

Which of Lamarck's ideas turned out to be true? Which turned out to be false?

Lamarck's ideas that evolution occurs and that an organism's traits are linked to its environment are true. Lamarck's idea that acquired characteristics can be inherited is false. ->Also, Lamarck's idea that species have an inborn drive to become more complex and perfect is false.

Charles Lyell

Lyell argued that the processes that changed Earth in the past were the same as the processes that are still changing Earth in the present. Knowing that Earth could change over time helped Darwin realize that life might change as well.

______ work explained how large geological features could be built up or torn down over long periods of time.

Lyell's

Thomas Malthus

Malthus thought that if the human population continued to grow unchecked, it would run out of living space and food. Darwin realized that this was true of all organisms, not just humans.

Embryonic Homologous Structures

Many homologous structures develop in the same order and in similar patterns during the embryonic, or pre-birth, stages of related groups. ->These similarities provide further evidence that the animals share common ancestors

Malthus's ideas led Darwin to conclude that......

Many more organisms are born than will survive and reproduce.

The Grants conducted their experiment to test which of the following processes?

Natural selection

Artificial Selection

Plant and animal breeders in Darwin's time used a process now known as artificial selection to improve their crops and livestock. In artificial selection, nature provides the variations, and humans select those they find desirable. ->Darwin experimented with artificial selection. The results from his experiments indicated natural variation was very important because it provided the raw material for evolution.

The Age of Earth and Fossils

Radioactive dating techniques have confirmed that Earth is ancient—approximately 4.5 billion years old. Recent fossil finds document intermediate stages in the evolution of many groups including whales, birds, and mammals.

Testing Natural Selection

Scientists have designed experiments to test natural selection. ->Observations of Galápagos finches confirm that competition and environmental change drive natural selection.

Larmarck's Theory: Impact

Scientists now know that most of Lamarck's ideas about evolution are incorrect. ->However, he correctly suggested that life is not fixed and was the first to offer a natural and scientific explanation for evolution. ->Further, he recognized that an organism's traits are linked to its environment.

Darwin spent most of his time exploring the continent of _________; he did not visit _____, _____, or ________

South America (Galapagos); North America, Asia, or Antartica

What explains the existence of similar but unrelated species?

Such species evolved features in common because they were exposed to similar pressures of natural selection.

When Darwin returned to England, he learned that the small brown birds he observed on the Galápagos Islands were all finches. They resembled South American finches. What hypothesis does this observation support?

The birds are descended from South American ancestors that traveled to the Galápagos Islands. The species have changed over time as they adapted to particular niches on each island.

How does the pattern of embryological development provide further evidence that organisms have descended from a common ancestor?

The early developmental stages of many vertebrates look very similar. Therefore, it is reasonable to assume that vertebrates are descended from a common ancestor.

What explains the distribution of finch species on the Galápagos Islands?

The finch species had descended with modification from a common mainland ancestor

Two biogeographical patterns that are significant to Darwin's theory:

The first is a pattern in which closely related species differentiate in slightly different climates. ->The Galápagos tortoises and finches follow this pattern. The second is a pattern in which very distantly related species develop similarities in similar environments. ->The rheas, ostriches, and emus fall into this pattern.

How does an animal's level of fitness relate to its chances of survival and reproduction?

The higher an animal's level of fitness in its particular environment, the better its chances for survival and reproduction.

Why might Darwin come to think that the finches of the Galápagos Islands might be related to the finches of South America, despite how different the birds were in appearance?

The islands are very close to the coast of South America and so the birds may have migrated from there.

What did the similarities between fossil animals and modern animals, like the glyptodont and armadillo, suggest to Darwin?

The similarities suggested to Darwin that the modern species may be related to the extinct fossil species.

Population Growth and Thomas Malthus

Thomas Malthus thought that if the human population continued to grow unchecked, it would run out of living space and food. ->Darwin realized that this was true of all organisms, not just humans.

Any inherited characteristic that increases an organism's chance of survival is considered an _______

adaptation

Biogeographers study where organisms live now and where they and their_____ lived in the past.

ancestors

Cytochrome c is a protein used for _________ in almost every living cell.

cellular respiration

Darwin's work offers insight into the living world by showing organisms are constantly ________________

changing or evolving

When individuals from a mainland bird population immigrate to various islands, natural selection may result in _________, but different, island species

closely related

The universal genetic code is used by almost all organisms to _________

direct protein synthesis

Homologous genes called Hox genes control timing and growth in _______

embryos

Over many generations, adaptation could cause successful species to ________ into new species.

evolve

________ is the ability of an individual to survive and reproduce in its specific environment

fitness

The science of ______ provides molecular evidence that supports evolutionary theory.

genetics

The data that the Grants collected proved that there is........

great variation of heritable traits among Galápagos finches

Proteins that are __________ share extensive structural and chemical similarities.

homologous

Hutton realized that Earth was much ______ than previously believed.

older

Common descent suggests that all species, living and extinct, are ______

related

Natural selection depends on the ability of organisms to _______, which means to leave descendants.

reproduce

What is another name for artificial selection?

selective breeding

Lyell thought most geological processes operated extremely ____ .

slowly

Relatively minor changes in an organism's genome can produce major changes in an organism's ________

structures

The processes that changed Earth in the past are_______ from the processes that operate in the present.

the same as