Chapter 16 Darwin's Theory of Evolution

How contribution helped Darwin: Malthus

-Darwin realized that this idea applied to all organisms. They don't all survive and reproduce, so which organisms do survive and why? -We're not overrun by bunnies or grasshoppers, so why do some survive and other don't?

What was Hutton's contribution?

-Earth must be older than a few thousand years, would take time to form mountains then wear them down. -Introduced deep time- the idea that Earth's history stretches back over a period of time so long that the human mind cannot even imagine.

What was Malthus' contribution?

-If human population grew unchecked, there wouldn't be enough living space and food for everyone. -3 items that limit population growth: war, famine, and disease.

Explain natural selection

-Natural selection does not make organisms "better". -Adaptations don't have to be perfect, just good enough to enable an organism to pass its genes to the next generation. -Natural selection also does not move in a fixed direction. -If local environment conditions change faster than a species can adapt to those changes, the species may become extinct.

What was Lamarck's contribution?

-Organisms could change during their lifetimes by selectively using or not using various parts of their bodies. -Acquired characteristics passed on to offspring. Wrong: That acquired traits s passed on.

How contribution helped Darwin: Lyell

-Realized that these processes can build the features of the Earth. -If the Earth can change, can life change too?

Describe homologous molecules.

-Some homologous proteins are found in all living things. One example is the protein cytochrome c, which functions in cellular respiration. -Genes can be homologous too (bc the all animals and plants have the same genetic code). Some examples of genes found in all living things are called the Hox genes. They help determine the head-to-tail axis in embryonic development. In vertebrates, homologous Hox genes direct the growth of front and hind limbs. Minor changes in an organism's genome can produce major changes in an organism's structure and the structure of its descendants.

What 3 patterns of biodiversity did Darwin note?

-That different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe. -Different ,yet related, animal species often occupied different habitats within a local area. -Some fossils of extinct species were similar to living species.

How did Lamarck propose that species evolve?

-That organisms could change during their lifetime by selectively using or not using various parts of their bodies. -Suggested that individuals cold pass these acquired traits on to their offspring, enabling species to change over time.

What is an example of Species Varying Locally?

-The Galápagos Islands, that have islands close to one another, yet they have different ecological conditions. He found that the shell of the tortoises varied from island to island. -He also found different types of finches with different types of beaks on the Galápagos Islands.

What does recent research on the Galápagos finches show about natural selection?

-The Grants have documented that natural selection takes place in wild finch populations frequently, and sometimes rapidly. -The Grants' work shows that variation within a species increases the likelihood of the species' adapting to and surviving environmental change.

What was Lyell's contribution?

-The processes that operate in the past are the same processes that are operating in the present. -Introduced uniformitarianism- must explain past events in terms of processes observable in the present. (Geological processes we see in action today are the same ones that shaped Earth millions of years ago).

Selective breeding by humans to enhance the useful traits of domesticated organisms is known as A. Artificial selection B. Lamarck's hypotheses C. Evolution D. Natural selection

A. Artificial selection

Darwin proposed that homologous structures are evidence of A. Shared ancestry B. Similar adaptations C. Embryonic development D. Similar functions

A. Shared ancestry

The wing of a bird and the wing of a grasshopper have similar functions, but they evolved independently. This is an example of A. Analogous structures B. Homologous molecules C. Vestigial structures D. Homologous structures

A. analogous structures

Darwins' observations of fossils of marine animals found several thousands of feet above sea levels can be explained by A. geological events causing the ancient seafloor to move to a higher elevation B. ancient people moving the fossils to higher ground C. Darwin's misidentification of fossils D. marine animals adapting to live far from the sea

A. geological events causing the ancient seafloor to move to a higher elevation

What does Darwin's mechanism for evolution suggest about living and extinct species?

According to the principle of common descent, all species, living and extinct, are descended from ancient common ancestors.

Traits altered by an individual organism during its lifetime.

Acquired Characteristic

____________ are characteristics that enable some members of a population to survive and reproduce "better".

Adaptations

Describe Life's common genetic code.

All living cells use information coded in DNA and RNA to carry information from one generation to the next and to direct protein synthesis. All common ancestors must have shared this code.

___________ structures are body parts that share a common function but not structure.

Analogous

Body parts that share common function, but not structure, are called _______ ________. (and example of one)

Analogous structures The wing of a bee and the wing of a bird.

Describe Lyell's evidence or description of how he came up with his theory

Ancient volcanoes released lava and gases, just as volcanoes do not. Ancient river slowly dug channels, and carved canyons in the past, just as they do today. Just like Hutton, Earth needed enough time for these changes to occur.

___________ __________ is the careful selection or organisms for mating based on traits found desirable by humans.

Artificial Selection

Hutton and Lyell's research suggested that Earth A. is only a few thousand years old B. changes slowly over long periods of time C. now has geological processes that are different than from those in the past D. has not changed much over time.

B. changes slowly over long periods of time

Darwin realized that Malthus' ideas about human population growth applied even more to other organisms such as why, A. insect populations grow unchecked each year B. oysters produce millions of eegs but only a few survive C. elephants are overpopulating the earth D. mammals carefully raise one or two young per year

B. oysters produce millions of eggs but only few survive

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

Biogeography

Studying biogeography can help scientists A. Learn hot to find countries on a map B. Decide how to observe a species of animal C. Make connections between where modern species and their ancestors lived D. Understand how an individual changes during its lifetime.

C. Make connections between where modern species and their ancestors lived

The DNA in yeasts, grizzly bears, centipedes and palm trees all share A. the same number of genes B. the same sequence of bases C. the same genetic code D. the same number of chromosomes

C. the same genetic code

What are some examples of adaptations?

Camouflage, mimicry, tiger's claws, colors, speed, strength, etc.

Name the 2 biogeographical patterns significant to Darwin's theory.

Closely related but different Distantley related but similar

What did Darwin suspect about the origin of different types of tortoises on the Galapagos Islands?

Come from mainland bird

The idea that 2 species alive today have both changed a little bit from a single ancient species is called __________.

Common Descent

Camouflage an mimicry are examples of A. Perfection B. Competition C. Mutation D. Adaptation

D. Adaptation

Individuals in a population must compete for A. Food B. Living Space C. Water D. All choices

D. All choices

When Darwin described certain organisms as "more fit" than other, he meant that they A. were physically stronger B. were more likely to evolve over time C. lived in a more suitable environment D. were better-suited to survive and reproduce

D. Were better-suited to survive and reproduce

Darwin's theory of descent with modification refers to A. Species adapting to changes in their environment B. Survival of the fittest C. Modification of an organism during its lifetime D. The process of species evolving from common ancestors.

D. the process of species evolving from common ancestors

Lamarck proposed that species change due to A. difference in survival B. genetic mutations C. competition for food D. use or disuse of organs

D. use or disuse of organs

Give 2 differences between Darwin's theory of evolution + Lamarck's?

D= accounted for variation L= No D= not. sel. L= acquired characteristics.

What is an example of Species Varying Over Time?

Darwin found a fossil of a glyptodont, a giant armored animal. It is extinct today, but it resembles armadillos a lot.

What is an example of Species Varying Globally?

Darwin found flightless, ground-dwelling birds called rheas living in the grasslands of South America. Rheas look like ostriches, yet rheas live only in South America, and ostriches only live in Africa. When Darwin visited Australia's grasslands, he found another large flightless bird, the emu. (why did different flightless birds live in similar grasslands across South America, Australia, and Africa, but not in the Northern Hemisphere?

Describe Variation and Adaptation.

Darwin knew that individuals have natural variations among their heritable traits. However, he concluded that some variants are better suited to life in their environment than others. Some predators that are faster or have longer claws may survive, and prey that are faster or better camouflaged may survive.

What hypothesis has the Grants been testing?

Darwin's theory that natural selection shaped the beaks of different bird populations as they became adapted to eat different foods.

Darwin proposed that living species are descended with modification, from common ancestors. This idea is called ______ _______ _________.

Descent with Modification (Hutton and Lyell come in with deep time bc to pass stuff from gen to gen takes a long time.

What happens to organisms with low levels of fitness?

Die or have few offspring

Give an example of artificial selection.

Dog breeder/horse breeder

Describe the similar patterns in embryological development.

Early developmental stages of many animals with backbones (vertebrates) look very similar. The same groups of embryonic cells develop in the same order and in similar patterns to produce many homologous tissues and organs in vertebrates. For example, despite the very different adult shapes and functions of the limb bones, all those bones develop from the same clumps of embryonic cells.

How contribution helped Darwin: Hutton

Earth needs to be old so evolution would have enough time to take place.

Why do the finches on the Galapagos Islands have different sized beaks?

Eat different foods

The Galapagos Islands are off the coast of what country?

Ecuador

How contribution helped Darwin: Lamarck

Even though incorrect... Recognized that there was a link between an organism's environment and its body structure. Helped pave the way for Darwin.

___________ is change over time.

Evolution

What do homologous structure and similarities in embryonic development suggest about the process of evolutionary change?

Evolutionary theory explains the existence of homologous structures adapted to different purposes as the result of descent with modification from a common ancestor.

Explain what Hutton recognized that was happening in the Earth.

Ex. That forces beneath the Earth can push rock layers, upward, tilting or twisting them in the process, creating mountain ranges. Mountains in turn, can be worn down by rain, wind, heat, and cold. These processes operate slowly, and Earth would have to be really old to make them happen.

What is inherited variation?

Example, you may look similar to your mother and father and have similar characteristics, but not everything is exactly the same.

True or False: Darwin set out on the Beagle with the intent of explaining the diversity of life on Earth.

False

True or False: The majority of a species offspring will survive.

False

True or False. Homologous structures are juse restricted to animals.

False. Biologists have identified homologies in plants, for example. They share homologous stems, roots, and flowers.

What was the "traditional" view about the age of the Earth in Darwin's time?

Few thousand years old

After looking at the finches at the Galápagos Islands for 35 years, and observing Darwin's hypothesis (that natural selection had shaped the beaks of different bird populations as they became adapted to eat different foods) on two testable assumptions. What were they?

First, for beak size and shape to evolve, there must be enough heritable variation in those traits to provide raw material for natural selection. . Second, differences in beak size and shape must produce differences in fitness.

Natural selection tends to increase A. Strength B. Size C. The level of perfection D. Fitness

Fitness

__________ is an organisms ability to survive and reproduce in its environment.

Fitness

What are 3 things that Darwin identified must be competed for in the "Struggle for existence"?

Food, space, mates

A ________ is the preserved remains of an ancient organism.

Fossil

What sources of evidence contributed to Darwin's presentation of his concept of natural selection?

Fossils, geogrpahic distribution, homologous body structure, sim in early development, genetics

(Analogy) Evolutionary theory: Darwin as _______________ theory: Lyell and Hutton

Geological

Give an example of Lamarck's Theory of Evolution.

Giraffe stretch neck and pass on (ex. of Lamarck's Theory)

Evolution is called the ______ ________ _____ ___ _______ _______ because the evolutionary theory offers insights that are vital to all branches of biology, from research on infectious disease to ecology.

Grand Unifying Theory of Life Sciences.

The Grants observed that each individual of the finches had anatomical characteristics like wing length, leg length, beak length, beak depth, beak color, feather colors, and total mass. The data recorded show that there is.......

Great variation of heritable traits among the Galápagos finches.

What was Darwin's contribution to science?

He developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors.

Structures that have different mature forms but develop from the same embryonic tissues are called ____________ __________.

Homologous Structure

Structures that are shared by related species and have been inherited from a common ancestor are called ________ _______.

Homologous structures.

Similarities and differences among homologous structures help determine what?

How recently species shared a common ancestor.

What did Hutton and Lyell conclude about Earth's history?

Hutton and Lyell concluded that Earth is extremely old and that the processes that changed Earth in the past are the same processes that operate in the present.

Describe the struggle for existence.

If more individuals are produced than can survive, members of a population must compete to obtain food, living space, and other limited necessities of life.

What was Malthus's view of population growth?

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

Under what conditions dos natural selection occur?

In any situation in which more individuals are born than can survive (Struggle for existence), there is natural heritable variation (variation and adaptation), and there is variable fitness among individuals (survival of the fittest)

Explain the similarity and differences in artificial and natural selection.

In both, only certain individuals in a population produce new individuals. But in natural selection, the environment, not a farmer or animal breeder, influences fitness.

Darwin proposed that natural selection results in a change in the inherited traits of a species that (increase or decrease) fitness.

Increase

Lamarck came up with the principle known as ________ ___ _________ ________. This states that a bird with an acquired trait, such as long legs, during its lifetime could pass that trait on to its offspring.

Inheritance of Acquired Characteristics

Darwin found fossils of many organisms that did not resemble any living species. How might this finding have affected his understanding of life's diversity?

It shows that species can die out, and that not all organisms are suited for survival. Life is diverse, but it is not always perfect. Organisms similar to the fossilized species did not exist because the species had died out.

_________ proposed that evolution occurs because of use or disuse of certain traits.

Lamarck

The 2 geologists that influenced Darwin were named ________ and _________.

Lyell + Hutton

Give 2 similarities between Darwin's theory of evolution and Lamarck's.

Made observations to come up with theory of evolution. Made predictions base on observations

__________ had ideas about human population growth and that war, disease, and famine act against this growth.

Malthus

In On the Origin of Species, Darwin combined his own thoughts with ideas from ________ and ________.

Malthus and Lamarck

Before Darwin, scientists thought variations among individuals in nature were simply _______ _________.

Minor defects

Give an example of natural selection.

Moths/penicillin

__________ are changes in the DNA sequence.

Mutation

Darwin proposed that evolution occurred through the process of ________ ________.

Natural Selection

________ _________ is the idea that organisms possessing adaptations that make them better suited at survival will have more offspring and pass on these "good" traits.

Natural Selection

In artificial selection, _________ provides the variation and _________ from these the ones they find desirable.

Nature, humans

Lyell stated that science must explain past events in terms of processes that can be ____________.

Observed

Look on page 468 for examples of homologous structures.

Ok thanks

What was the name of Darwin's book that was published in 1859?

On the Origin Species

Why do dolphins retain structures with little or no function?

One possibility is that the presence of the structure does not affect an organism's fitness, and, therefore, natural selection does not act to eliminate it.

The same group of embryonic cells develop in the same _______ and in similar _________ to produce the tissues and organs of all vertebrates.

Order, patterns,

How did Darwin's problem of struggling to find fossils?

Paleontologists since Darwin has discovered hundreds of fossils that document intermediate stages in the evolution of many different groups of modern species. For ex. recently discovered fossils sows evolution of whales from ancient land mammals.

How does the geographic distribution of species today relate to their evolutionary history?

Patterns in the distribution of living and fossil species tell us how modern organisms evolved from their ancestors.

When Darwin looked at the different shaped beaks of the birds on the different islands, he proposed that natural selection had shaped the beaks of different bird populations as they became adapted to eat different foods. They wasn't any way to test it until _______ and __________ of Princeton University

Peter and Rosemary Grant

How was Darwin's difficulty of determining the age of Earth fixed after Darwin's time?

Physicists discovered radioactivity. They used this to establish the age of certain rocks and fossils. Radioactivity indicates that Earth is about 4.5 billion years old.

Hutton recognized the connections between geological _________ and geological ________.

Processes and features (mountains, valleys, layers of rock)

Organisms that do not have a common ancestor but live in __________ environments will develop features in common with each other.

Similar

Describe Distantly Related but Similar

Similar habitats around the world are home to animals and plants that are distantly related. Example of ground-dwelling birds inhabiting similar grasslands in Europe, Australia, and Africa. The different body structures in the rheas, ostriches, and emu suggested that they evolved from different ancestors. Similarities among these animals provide evidence that similar selection pressures had caused distantly related species to develop similar adaptations.

__________ is a group of similar organisms that can reproduce successfully with others of the same type.

Species

What are the 3 distinctive patterns of biological diversity?

Species vary globally, locally, and over time

Name the 3 conditions under which natural selection occurs.

Struggle for existence Variation and adaptation Survival of the Fittest

Biologists test whether structures are homologous by (3 things)...

Studying anatomical details, the way structures develop in the embryos, and the pattern in which they appeared over evolutionary history.

Another term for the process of natural selection is _________ _______ _________ _________.

Survival of the Fittest

The difference in rates of survival and reproduction is called ________ ___ ____ _______.

Survival of the Fittest.

What did the evidence of the 3 biological patterns suggest?

That species are not fixed and that they could change by some natural process.

What are the 2 potential difficulties for Darwin's theory?

The age of Earth Gaps in fossil records

Describe Closely but Different using Galápagos Islands.

The biogeography of Galápagos suggested that populations on the island had evolved from mainland species. Over time, natural selection on this islands produced variations within among populations that resulted in different, but closely related, island species.

Give an example of vestigial structures.

The hipbones on bottlenose dolphin are vestigial structures. In their ancestors, hipbones played a role in terrestrial locomotion. However, as the dolphin lineage adapted to sea life, this function was lost.

Describe Survival of the Fittest.

Those with adaptation that are well suited to their environment can survive and reproduce, but individuals that are not well suited to their environment either die without reproducing or leave few offspring.

Lamarck was the first to recognize what?

To suggest that species are not fixed. Also first to try to explain evolution scientifically using natural processes. Also recognized that there is a link between organism's environment and its body structures.

_________ are differences among individuals of a species.

Variations

__________ structures have lost their original function.

Vestigial

Features of animals that are so reduced in size that they serve no function are called _________ _________.

Vestigial organ

_________ _______ are inherited from ancestors but have lost much or all of their original function due to different selection pressures acting on the descendant. (and example)

Vestigial structure

Malthus proposed that only ___________, __________, and ____________ worked against population growth of humans.

War, famine, disease

Lamarcks' ideas, and say how some were wrong.

What he thought: -All organisms strived to be perfect. -Thought organisms could change the size or shape of their organs by using their bodies in new ways. -Thought they could pass acquired characteristics on to next generation. Wrong: -Animals do not strive to be perfect -Do not change organs with use or disuse of them -Cannot pass acquired characteristics to next generation.

When Darwin first saw the Galápagos finches, he thought they were ______, _____, and ______ because they looked so different from one another. Once Darwin learned that the birds were all finches, he hypothesized that they had descended from a common ancestor.

Wrens, warblers, black-birds

At the molecular level, the universal genetic code and homologous molecules provide evidence of.....

common descent.

Changes in food supply created selection pressure that caused finch populations to evolve within decades. (Ex. if it was dry out, bigger beaks are more likely to survive, so then the average population changed into bigger beaks)

cool thanks

According to the principle of common descent, all species, living and extinct, are .....

descended from ancient common ancestors.

The most troublesome "missing information" for Darwin had to do with __________.

heredity.

When food becomes scarce during dry periods, birds with the largest beaks are more likely to _________. As a result, the average beak size in this finch population has _______ dramatically.

more likely to survive.

Similar patterns in embryological development provide further evidence that...

organisms have descended from a common ancestor.

The "tree-thinking" implies that all organisms are _________.

related

The clue to common descent is common ________, not common _________.

structure function