16.3 Darwin presents His case

evolve

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

related

11. Common descent suggests that all species, living and extinct, are ------.

descent with modification

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

fossil record

13. The -------- provides physical evidence of descent with modification over long periods of time.

descended

9. Every organism alive today ----- from ancestors who survived and reproduced.

theory

A well-supported explanation of phenomena that have occurred in the natural world

Such individuals die or leave fewer offspring.

According to Darwin's theory, what happens to individuals whose characteristics are not well suited to their environment?

An inherited characteristic that increases an organims's ability to survive

Adaptation

a. year 1 b. the number of dark-colored frogs increased. The number of light-coloured frogs decreased. c. dark coloring d. as the pond water grows darker, the dark-colored frogs are less likely to be seen asn eatern by predators. they are more fit than the light-colored frogs and thereofre more likely to survive and reproduce. d. in artificial selection, humans determine the desried characteristicx and only breed anials with those characeristics. In natural seltcion, nature determines the deired characterisics an donly organisms with these charactreiest survive to reproduce.

An adaptation is an inherited characteristic that helps an organism survive and reproduce in its environment. Over time, adaptations become more and more common in a population. For example, suppose that the water in a pond gets darker over a period of four years. The diagrams and table below show what might happen to a frog population living in the pond. a. In which year was the number of light-colored frogs greater than the number of dark-colored frogs? b. How did the numbers of light- and dark-colored frogs change over time? c. Which adaptation is best suited for the pond in Year 3? Circle the best answer. Light Coloring Dark Coloring d. How do dark-colored frogs show "survival of the fittest"?

Adaptation

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

b. adaptation

Any inherited characteristic that increases an organism's chance of survival a, fitness b. adaptation c. natural selection

t

Any inherited characteristic that increases an organism's chance of survival is considered an adaptation. T or F

evolution

Change over time

a,c,d

Circle the letter of each idea that is part of Darwin's theory of evolution. (more than one answer) a. There is variation in nature. b. Fewer organisms are produced than can survive. c. There is a struggle for existence. d. Species change over time

c,d

Circle the letter of each sentence that is true about Darwin's book, On the Origin of Species. (more than 1 answer) a. It was published in 1869. b. It was ignored when it was first published. c. It contained evidence for evolution. d. It described natural selection.

a,b,c

Circle the letter of each sentence that is true about artificial selection. a. It is also called selective breeding. (more than 1 answer) b. It occurs when humans select natural variations they find useful. c. It produces organisms that look very different from their ancestors. d. It is no longer used today

a, b

Circle the letter of each sentence that is true about natural selection. a. It selects traits that increase fitness. b. It takes place without human control. c. It can be observed directly in nature. d. It leads to an increase in a species' fitness

a

Circle the letter of the way Darwin explained the distribution of finch species on the Galápagos Islands. a. They had descended with modification from a common mainland ancestor. b. They had descended with modification from several different mainland ancestors. c. They had remained unchanged since arriving on the Galápagos from the mainland. d. They had become more similar to one another after arriving on the Galápagos

descent with modification

Darwin believed that all organisms on Earth are united into a single tree of life by

Individuals that are better suited to their environment survive and reproduce most successfully

Explain what Darwin meant by the phrase survival of the fittest.

Darwin thought that such species evolved features in common because they were exposed to similar pressures of natural selection

How did Darwin explain the existence of similar but unrelated species?

They document the fact that life on Earth has changed over time.

How do fossils that formed in different rock layers provide evidence of evolution?

The healthIer it is the more it will survive and reproduce

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

false

Is the following sentence true or false? Adaptations can be physical characteristics but not more complex features such as behavior

f

Is the following sentence true or false? Darwin argued that living things have been evolving on Earth for thousands of years t or f

F: inherited

Natural selection acts on acquired traits. True or false

reproduce

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

fitness

Natural selection is the ability of an individual to survive and reproduce in its specific environment T or F

c. natural selection

Survival of the fittest a, fitness b. adaptation c. natural selection

a, fitness

The ability of an individual to survive and reproduce in its specific environment a, fitness b. adaptation c. natural selection

fitness

The ability to survive and reproduce in a specific environment

vestigial

The kind of organs that are so reduced in size they are just traces of homologous organs in other species

homologous

The kind of structures that have different mature forms but develop from the same embryonic tissues

fossils

The preserved remains of ancient organisms

common descent

The principle that all species were derived from common ancestors is known as ----

descent with modification

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

common

The type of descent that explains why all species are linked in a single tree of life

artificial

The type of selection that humans control

natural

The type of selection that increases an organism's fitness in its environment

To survive for yourself

What does the phrase struggle for existence mean?

They have been confirmed and expanded by scientific advances in biology, geology, and physics

What is the status of Darwin's hypotheses today?

developing a scientific hypothesis to explain how evolution occurs

What was Darwin's greatest contribution?

Because they get use to the surroundings

Why is camouflage considered an adaptation?

how well an organism can survive and reprdouce in an environment

fitness

the process by which organims that are ;most suited to their enviomnent survive and reproduce

natural selection