Biology Chapter 16

What did biologists suggest about life?

Biologists suggested that life had also changed.

Species Vary Locally: Tortoises from Galapagos Islands (5)

1. The shape of the tortoises' shells corresponds to different habitats. 2. Isabela Island has high peaks, is rainy, and has abundant vegetation that is close to the ground. 3. A tortoise from Isabela Island has a done-shaped shell and short neck. 4. Hook Island, in contrast, is flat, dry, and has sparse vegetation. 5. A long neck and a shell that is curved and open around the neck and legs allow the Hood Island tortoise to reach sparse, high vegetation.

What must members of a population compete for? (3)

1. To obtain food 2. Living space 3. Other limited necessities of life

What does evolutionary theory offer today?

1. Today, evolutionary theory-which includes natural selection-offers insights that are vital to all branches of biology, from research on infectious disease to ecology. 2. That's why evolution is often called the grand unifying theory of the life of sciences.

What do fossils connect the dots between? (3)

1. Whales and ancient land mammals 2. Dinosaurs and birds 3. Fish and four-legged land animals

What did animals with similar structures evolve from?

Animals with similar structures evolved from a common ancestor with a basic version of that structure.

What is an adaptation?

Any heritable characteristic that increases an organism's ability to survive and reproduce in its environment is called an adaptation.

What are variations?

Differences among individuals within the same species.

What do differences in adaptations affect?

Differences in adaptations affect an individual's fitness.

What provides evidence that animals evolved from different ancestors?

Differences in body structures provides evidence that animals evolved from different ancestors.

When was the scientific view of the natural world shifting?

During Darwin's time the scientific view of the natural world was shifting.

During their study, what did the Grants do?

During their study, the Grants periodically recapture the birds.

What is biogeography?

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

What did biogeography of Galapagos species suggest?

Biogeography of Galapagos species suggested that populations on the island had evolved from mainland species.

Example of vestigial structures? (2)

-The hipbones of bottlenose dolphins are vestigial structures. In ancestors, hipbones played a role in terrestrial locomotion. However, as the dolphin lineage adapted to life at sea, this function was lost. -A vestigial structure in humans is the appendix

What can adaptations involve? (3)

1. Body parts or structures 2. Camouflage or mimicry 3. Physiological functions (i.e. photosynthesis)

What two biogeographical patterns are significant to Darwin's theory?

1. Closely related species differentiate in slightly different climates. 2. Very distantly related species develop similarities in similar environments.

2 forms of evidence that species vary over time

1. Collected fossils - preserved remains of ancient organisms 2. Noticed that fossils of extinct animals were similar to living species

What three patterns of biodiversity did Darwin note?

1. Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe. 2. Darwin noticed that different, yet related, animal species often occupied different habitats within a local area. 3. Darwin noticed that some fossils of extinct animals were similar to living species.

Species Vary Locally: Birds (2)

1. Different varieties of mockingbirds, all resembled mockingbirds from South America. 2. In addition, Darwin noticed different types of small brown birds on the islands with beaks of different shapes.

What were the two testable assumptions that Darwin's hypothesis rested on?

1. First, for beak size and shape to evolve, there must be enough heritable variation in those traits to provide raw material for natural selection. 2. Second, differences in beak size and shape must produce differences in fitness.

What is are examples of species varying globally? (2)

1. Found 3 flightless birds specific to these areas: - Rhea in South America - Ostrich in Africa - Emu in Australia 2. Rabbits in European grassland and not in Australia's grassland where kangaroos are found and kangaroos are not found anywhere else.

What were the 3 distinctive patterns of biological diversity that Darwin noticed?

1. Species vary globally 2. Species vary locally 3. Species vary over time

What are 3 ways that biologists test whether structures are homologous?

1. Studying anatomical details 2. The way structures develop into embryos 3. The pattern in which they appeared over evolutionary history

What were the 3 observations he made about the animals with the patterns? (weird question wording)

1. The Galapagos mockingbirds turned out to belong to three separate species found nowhere else. 2. The little brown birds were actually all species of finches, also found nowhere else, though they resembled a South American finch species. 3. The same was true of tortoises, marine iguanas, and many plants that Darwin had collected.

What is fitness?

Fitness is how well an organism can survive and reproduce in its environment.

What anatomical characteristics did the Grants record for each individual finch?

For each individual, the Grants record anatomical characteristics like 1. wing length 2. leg length 3. beak length 4. beak depth 5. beak color 6. feather color 7. total mass

What did Darwin use for evidence of descent with modification?

For evidence of descent with modification over long periods of time, Darwin pointed to the fossil record.

From generation to generation, populations continue to change as....

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

How is variation passed?

From parents to offspring

Besides proteins, what else can be homologous?

Genes can be homologous, too.

What did genetics provide evidence for?

Genetics provides evidence for evolution in the discoveries of Mendel and Watson and Crick.

What did geologists suggest about Earth's age?

Geologists suggested that Earth was ancient and changed over time.

What do geologists use to establish the age of certain rocks and fossils?

Geologists use radioactivity to establish the age of certain rocks and fossils.

What did Darwin note about the finches' appearances?

He noted that several finch species have beaks of very different sizes and shapes. Each species uses its beak like a specialized tool to pick up and handle its food. Different types of foods are most easily handled with beaks of different sizes and shapes.

What did Darwin wonder about how different Galapagos species evolved?

He wondered if different Galapagos species might have evolved from South American ancestors.

Historical records are incomplete, but...

Historical records are incomplete but the evidence tells a story of evolutionary change.

What do homologous proteins share?

Homologous proteins share extensive structural and chemical similarities.

What are homologous structures?

Homologous structures are structures that are shared by related species and that have been inherited from a common ancestor, (but have a different function i think?)

What was Hutton and Lyell's contribution to Darwin's theory of descent with modification?

Hutton and Lyell's contribution to Darwin's theory is that deep time gave enough time for natural selection to act.

How may a species become extinct?

If environmental conditions change faster than a species can adapt to those changes, the species may become extinct.

What happens to some traits if a local environment changes?

If local environmental conditions change, some traits that were once adaptive may no longer be useful, and different traits may become adaptive.

If more individuals are produced than survive, what do the members of a population need to do?

If more individuals are produced than survive, members of a population must compete.

What is descent with modification?

It is an idea proposed by Darwin that states that living species are descended, with modification, from common ancestors.

Individuals with a LOW fitness level are...

NOT well suited to the environemnt, and will most likely die out

How does natural selection move?

Natural selection DOES NOT move in a fixed direction. There is no one perfect way of doing something. Natural selection is simply a process that enables organisms to survive and reproduce in a local environment.

What doesn't natural selection do?

Natural selection does not make organisms "better." Adaptations just have to be good enough to enable an organism to reproduce.

Under what conditions does natural selection occur? (3)

Natural selection occurs when: 1. More individuals are born than can survive (the struggle for existence) 2. There is inherited variation (variation and adaptation) 3. Different fitness levels among individuals (survival of the fittest)

What traits does natural selection act on?

Natural selection only acts on INHERITED TRAITS because those are the only characteristics that parents can pass on to their offspring.

What does natural variation provide?

Natural variation provides the raw material for evolution.

What did people think about Darwin's proposal (on the last card) until Peter and Rosemary Grant of Princeton University came along?

No one thought there was a way to test this hypothesis until Peter and Rosemary Grant of Princeton University came along.

Not all homologous structures have...

Not all homologous structures have important functions.

What is one of the best examples of natural selection in action?

One of the best examples of natural selection in action comes from observations of animals living in their natural environment-the Galapagos finches.

What could Darwin's voyage be described as?

One of the most important scientific voyages in history.

What is one way to gather evidence for evolutionary change?

One way to gather evidence for evolutionary change is to observe natural selection in action.

What is the principle of common descent?

That all species - living and extinct- are descended from ancient common ancestors.

Individuals with a HIGH fitness level are...

well suited to the environment and can survive and reproduce

What are examples of artificial selection?

-Farmers only breeding trees that produced the largest fruit -Farmers only breeding cows that produced the most milk

What did Darwin do with the 3 distinctive patterns of biological diversity he noticed? (2)

-He thought about the patterns seen -Sent specimens for identification

All living things use ___ to make ____ to make _______.

All living things use DNA to make RNA to make PROTEINS.

How can molecular biology be used to trace the process of evolution?

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

Before Darwin, what were variations known as?

Before Darwin, variations were simply minor defects.

What are analogous structures?

Body parts that share a common function, but not a common structure

What did breeders know about organisms?

Breeders knew organisms varied

What caused finch populations to evolve within decades? What surprised researchers about these changes?

Changes in food supply created selection pressure that caused finch populations to evolve within decades. This evolutionary change occurred much faster than many researchers thought possible.

Common descent =

Common descent=COMMON STRUCTURE, not common function. A bird's wing and a horse's front limb have different functions but similar structures.

What did Darwin's study of fossils convince him?

Darwin's study of fossils convinced him life evolved, but not enough intermediate forms were found.

What is Darwin's theory of Natural Selection?

Darwin's theory of Natural selection is the process by which organisms with variations most suited to their environment survive and leave more offspring.

What did Darwin base his explanation for diversity of life on?

Darwin based his explanation for the diversity of life on the idea that species change over time.

What did Darwin call the selective breeding process where the breeders used the variation in organisms to improve crops and livestock?

Darwin called this selective breeding process artificial selection, a process in which nature provides the variations, and humans select those they find useful.

What did Darwin collect?

Darwin collected specimens of plants and animals.

What did Darwin describe this competition as?

Darwin described this as the "struggle for existence."

What was Darwin's contribution to science?

Darwin developed a theory of evolution that explains how organisms evolved over time through descent from common ancestors.

What did Darwin not know about heredity and variation?

Darwin had no idea how heredity worked or what caused variation, but he did know variation occurred in all species.

What did Darwin hypothesize about the Galapagos finches he observed?

Darwin hypothesized that the Galapagos finches he observed had descended from a common ancestor.

What were the observations that Darwin made about?

Darwin made observations about characteristics and habitats of different species.

What did Darwin propose about what shaped the beaks of different bird populations?

Darwin proposed that natural selection had shaped the beaks of different bird populations as they became adapted to eat different foods.

What did Darwin propose about adaptations?

Darwin proposed that, over many generations, adaptation could cause successful species to evolve into new species.

What ship did Darwin sail on and where?

Darwin sailed on the HMS Beagle along South America.

Early developmental stages of many animals with backbones look....

Early developmental stages of many animals with backbones look very similar.

About how many years old is Earth?

Earth is about 4.5 billion years.

How long does evolution take and how old must Earth be?

Evolution takes a long time. Earth must be very old - (Hutton and Lyell)

What do homologous structures 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.

What does an evolutionary tree show?

Evolutionary tree shows how descent with modification could produce the diversity of life.

In Darwin's day, what could biologists only study?

In Darwin's day, biologists could only study similarities and differences in visible structures.

How is inherited variation used in artificial selection?

In artificial selection, nature provides the variations, and humans select those they find useful.

What does survival mean in evolutionary terms?

In evolutionary terms, survival means reproducing and passing adaptations on to the next generation.

In natural selection, the _______ influences ________.

In natural selection, the ENVIRONMENT influences FITNESS.

What does every individual have?

Individuals have variations, and SOME VARIATIONS ARE BETTER SUITED THAN OTHERS.

What happened when Darwin published his explanation for evolution?

It changed the way people understood the living world.

Over time, natural selection on the islands produced what?

It produced variations among populations that resulted in different, but closely related, island species.

What happens to the evolutionary theory as new data is gathered?

Like any scientific theory, evolutionary theory is constantly reviewed as new data are gathered.

Biochemical similarities are best explained by Darwin's conclusion, which is:

Living organisms evolved through descent with modification from a common ancestor.

Why did Darwin look for larger patterns in the animals?

Looked for larger patterns to explain the diversity he observed.

What do mutations and crossing over produce?

Mutations and crossing over produce variations ON WHICH NATURAL SELECTION OPERATES.

What do patterns in the distribution of living and fossil species tell us?

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

What do recently discovered fossils form?

Recently discovered fossils form series that trace the evolution of modern species from extinct ancestors.

What do researchers still debate today?

Researchers still debate important questions, such as precisely how new species arise and why species become extinct.

How does embryology provide evidence of descent with modification?

Same groups of embryonic cells develop in the same order and in similar patterns to produce many homologous tissues and organs in vertebrates providing evidence of descent with modification.

What did scientists note about vertebrates?

Scientists had noted that all vertebrate limbs had the same basic bone structure.

Example of distantly related but similar animals (1 example, 3 animals)

Similar ground-dwelling birds (rheas, ostriches, and emus) inhabit similar grasslands in Europe, Australia, and Africa.

Similarities among those animals provide evidence that...

Similarities among those animals provide evidence that similar selection pressures had caused distantly-related species to develop similar adaptations.

What do similarities and differences among homologous structures help determine?

Similarities and differences among homologous structures help determine how recently species shared a common ancestor.

What did the Grants document about natural selection?

The Grants have documented that natural selection takes place in wild finch populations frequently, and sometimes rapidly.

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

The Grants have documented that natural selection takes place in wild finch populations frequently, and sometimes rapidly.

What did the Grants test these hypotheses on?

The Grants have tested these hypotheses on the medium ground finch (Geospiza) on the island of Daphne Major.

What did the Grants realize about Darwin's hypothesis?

The Grants realized that Darwin's hypothesis rested on two testable assumptions.

The Grants' data also confirms that ______ and _______ ______ drive natural selection.

The Grants' data also confirm that competition and environmental change drive natural selection.

What has the Grants' data shown about the finches' beak size?

The Grants' data have shown that individual finches with different-size beaks have better or worse chances of surviving both seasonal droughts and longer dry spells.

What did the Grants' work show about variation within a species?

The Grants' work shows that variation within a species increases the likelihood of the species' adapting to and surviving environmental change.

What does the Grants' work show about variation within a species?

The Grants' work shows that variation within a species increases the likelihood of the species' adapting to and surviving environmental change.

What did the evidence from Darwin's exploration suggest?

The evidence suggested that species are not fixed and that they could change by some natural process.

What is evolution?

The process of change over time is called evolution.

What does the evolutionary tree link?

The tree links all organisms.

1 example of an analogous structure

The wing of a bug and the wing of a bird are analogous structures.

What is there significant uncertainty about?

There is also significant uncertainty about exactly how life began.

What did the Grants record?

They record which individuals are alive and which have died, which have reproduced and which have not.

What does descent with modification imply?

This aspect implies that life has been on Earth for a very long time- enough time for all this descent with modification to occur.

What is survival of the fittest?

This difference in rates of survival and reproduction is called survival of the fittest.

What is the genetic code like in organisms?

This genetic code is nearly identical in almost all organisms, including bacteria, protists, plants, fungi, and animals.

Why was the Daphne Major island good for the Grants' experiments?

This island is large enough to support good-sized finch populations, yet small enough to allow the Grants to catch, tag, and identify nearly every bird of the species.

What is the similarity in genetic code evidence for?

This similarity in genetic code is evidence that all organisms evolved from common ancestors.

How did Darwin find an explanation for change in nature?

To find an explanation for change in nature, Darwin studied change produced by plant and animal breeders.

How is variation used?

To improve crops and livestock.

What is the key to understanding the natural world?

To scientists, evolution is the key to understanding the natural world.

Today, ______ is not limited to physical structures.

Today, homology is not limited to physical structures.

What may happen to unnecessary traits when environmental conditions change?

Traits that don't matter much under one set of environmental conditions became adapted as the environment changes during a drought.

What are vestigial structures?

Vestigial structures are INHERITED, but have lost their original function due to different selection pressures acting on the descendant.

When food becomes scarce during dry periods, which bird is most likely to survive and what is a result of this?

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

Without heritable variation in beak sizes, what would happen to the finch?

Without heritable variation in beak sizes, the medium ground finch would not be able to adapt to feeding on larger, tougher seeds during a drought.

along what coast are the galapagos islands?

along the coast of ecuador

What are remaining questions about evolution?

any questions that remain are about how evolution works-not whether evolution occurs