Human Evolution - Chapter 1: How Evolution Works

Front 1

_________ are constructed components that interact to help the organism survive and reproduce.

Back 1

adaptations


(Chapter 1, p. 2)

Front 2

Define adaptation.

Back 2

A feature of an organism created by the process of natural selection designed to help the organism survive and reproduce.


(Chapter 1, p. 2 & Glossary p. A3)

Front 3

Before Darwin's theory of evolution by natural selection, people believed that adaptations were the result of _________ ________.

Back 3

divine creation


(Chapter 1, p. 4)

Front 4

T or F:
Charles Darwin was born into a poor family and was expected to be a doctor or country parson.

Back 4

False:
Darwin was born into a well-to-do, intellectual and politically liberal family in England where he was expected to become a doctor. When he failed at that, his family expected him to become a country parson.

(Chapter 1, pp. 4 - 5)

Front 5

From what three postulates does Darwin's theory of adaptation, explaining how species change through time, follow?

Back 5

1. The ability of a population to expand is infinite, but the ability of any environment to support populations is always finite. (struggle for existence)

2. Organisms within populations vary, and this variation affects the ability of individuals to survive and reproduce. (variation in fitness)

3. This variation is transmitted from parents to offspring. (the inheritance of variation)

(Chapter 1, pp. 5 - 6)

Front 6

_________ _________ refers to traits that confer advantages in survival and reproduction are retained in the population, and traits that are disadvantageous disappear.

Back 6

natural selection


(Chapter 1, p. 6)

Front 7

T or F:
When Darwin coined the term natural selection, he was making a deliberate analogy to the artificial selection practiced by animal and plant breeders of his day.

Back 7

True


(Chapter 1, p. 6)

Front 8

Define natural selection.

Back 8

The process that produces adaptation. Natural selection is based on three postulates: (1) the availability of resources is limited; (2) organisms vary in the ability to survive and reproduce; and (3) traits that influence survival and reproduction are transmitted from parents to offspring. When these three postulates hold, natural selection produces adaptation.

(Glossary, p. A11)

Front 9

Theologian ___________ _________ used a discussion of the human eye to argue for the existence of God in his book Natural Theology, published in 1802.

Back 9

William Paley
He argued that the eye is clearly designed for seeing; and where there is design in the natural world, there certainly must be a heavenly designer.


(Chapter 1, p. 4)

Front 10

Who were Peter and Rosemary Grant?

Back 10

They were biologists at Princeton University that conducted a landmark study of the ecology and evolution of one particular species of Darwin's finches on the island Daphne Major of the Galapagos islands. The Grants were able to document how Darwin's three postulates lead to evolutionary change when a drought hit the island.

(Chapter 1, p. 7)

Front 11

How did the events on the island of Daphne Major embody all three of Darwin's postulates?

Back 11

First, the supply of food on the island was not sufficient to feed the entire population, and many finches did not survive the drought. Second beak depth varied among the birds on the island, and this variation affected the birds survival. Deep beaked birds ate large, hard seeds while shallow-beaked birds ate small, soft seeds. During the drought abundance of small seeds decreased, thus individuals with deeper beaks were more likely to survive than individuals with shallower beaks. Third, parents and offspring had similar beak depths.

(Chapter 1, pp. 7 - 9)

Front 12

Define morphology.

Back 12

The form and structure of an organism.


(Glossary, p. A11)

Front 13

An organism's size, shape and composition is called it's __________.

Back 13

morphology


(Chapter 1, p. 9)

Front 14

T or F:
Selection preserves the status quo when the most common type is the best adapted.

Back 14

True


(Chapter 1, p. 9)

Front 15

T or F:
Selection is required to change a population, and selection is also required to keep a population the same.

Back 15

True
When a selective equilibrium exists within a population, the process that produces this equilibrium state is called stabilizing selection.


(Chapter 1, p. 10)

Front 16

Define stabilizing selection.

Back 16

Selection pressures that favor average phenotypes. Stabilizing selection reduces the amount of variation in the population but does not alter the mean value of the trait.

(Glossary, pp. A14 - A15)

Front 17

________ is a steady state in which neither gene frequencies nor genotypic frequencies change.

Back 17

Equilibrium
It is produced by the process called stabilizing selection.


(Chapter 1, p.10)

Front 18

T or F:
Populations do not remain static over the long run unless selection is operating.

Back 18

True


(Chapter 1, p. 10)

Front 19

T or F:
Evolution always leads to change in the same direction.

Back 19

False
Evolution need not always lead to change in the same direction. Natural selection causes organisms to change so that they are better adapted to their environment - often environments fluctuate over time, thus adaptations fluctuate as well.


(Chapter 1, p. 10)

Front 20

________ are populations of varied individuals that may or may not change through time.

Back 20

Species


(Chapter 1, p. 11)

Front 21

According to Darwin's theory a ________ is a dynamic population of individuals.

Back 21

species


(Chapter 1, p. 11)

Front 22

T or F:
The characteristics of a particular species will be static over a long period of time only if the most common type of individual is consistently favored by stabilizing selection.

Back 22

True


(Chapter 1, p. 11)

Front 23

T or F:
Stasis is the natural state of species.

Back 23

False
Stasis is not the natural state of species.


(Chapter 1, p. 11)

Front 24

T or F:
Adaptation results from the competition among individuals, not between entire populations or species.

Back 24

True


(Chapter 1, p. 11)

Front 25

Selection produces adaptations that benefit _________.

Back 25

individuals
(adaptations may or may not benefit the population or species)

Ex. Selection often leads to changes in behavior or morphology that increase the reproductive success of individuals but decrease the average reproductive success of the group, population or species.


(Chapter 1, p. 11)

Front 26

________ is the term that demographers use for the ability to produce offspring.

Back 26

Fecundity


(Chapter 1, p. 12)

Front 27

T or F:
The idea that natural selection operates at the level of the individual is a key element in understanding adaptation.

Back 27

True


(Chapter 1, p. 12)

Front 28

T or F:
The accumulation of small variations by natural selection can also give rise to complex adaptations.

Back 28

True


(Chapter 1, p. 12)

Front 29

Why are small variations important?

Back 29

Over time, they can lead to complex adaptations.


(Chapter 1, p. 12)

Front 30

What are the two categories of variation?

Back 30

Continuous and Discontinuous


(Chapter 1, p. 12)

Front 31

Give an example of continuous variation.

Back 31

The distribution of heights in people. Humans grade smoothly from one extreme to the other (short to tall), with all the intermediate types represented.


(Chapter 1, p. 12)

Front 32

Define continuous variation.

Back 32

Phenotypic variation in which there is a continuum of types.


(Glossary, p. A5)

Front 33

Define discontinuous variation.

Back 33

Phenotypic variation in which there are a discrete number of phenotypes with no intermediate types.


(Glossary, p. A6)

Front 34

Give an example of discontinuous variation.

Back 34

Pea color in Mendel's experiments is an example of discontinuous variation.


(Chapter 1, p. 12)

Front 35

________ variation is where a number of distinct types exist with no intermediates.

Back 35

Discontinuous


(Chapter 1, p. 12)

Front 36

T or F:
Discontinuous variants are usually rare in nature.

Back 36

True


(Chapter 1, p. 13)

Front 37

________ __________ is not important for the evolution of complex adaptations, because complex adaptations are extremely unlikely to arise in a single jump.

Back 37

Discontinuous variation


(Chapter 1, p. 13)

Front 38

Complex _______ can arise through the accumulation of small random variations by natural selection.

Back 38

adaptations


(Chapter 1, p. 13)

Front 39

_______ variation is essential for the evolution of complex adaptations.

Back 39

Continuous


(Chapter 1, p. 13)

Front 40

Selection can give rise to great complexity starting with small random variations because it is a ________ process.

Back 40

cumulative


(Chapter 1, p. 14)

Front 41

T or F:
The evolution of complex adaptations requires all of the intermediate steps to be favored by selection.

Back 41

True


(Chapter 1, p. 14)

Front 42

__________ is the evolution of similar adaptations in unrelated species.

Back 42

Convergence


(Chapter 1, p. 16)

Front 43

T or F:
Sometimes unrelated species have independently evolved the same complex adaptation.

Back 43

True
This suggests that the evolution of complex adaptations by natural selection is not a matter of mere chance.


(Chapter 1, p. 16)

Front 44

Give an example of convergence.

Back 44

The evolution of camera-type eyes in both vertebrates and mollusks is an example of convergence.

Other examples of convergence:
Similarities between marsupials of Australia and South America and placental mammals of the rest of the world.


(Chapter 1, pp. 15 - 16)

Front 45

T or F:
Natural selection can cause evolutionary change that is much more rapid than we can commonly observe in the fossil record.

Back 45

True


(Chapter 1, p. 17)

Front 46

Give an example of rapid evolutionary change.

Back 46

Change in beak morphology in Darwin's finches observed by Peter and Rosemary Grant on the island of Daphne Major.


(Chapter 1, p. 19)

Front 47

Darwin's ____________, published in 1859, proposed that new species and other major evolutionary changes arise by the accumulation of small variations through natural selection.

Back 47

On the Origin of Species
(It was a best seller, but his theory was not widely embraced.)


(Chapter 1, p. 21)

Front 48

T or F:
Darwin couldn't convince his contemporaries that evolution occurred through the accumulation of small variations because he couldn't explain how variation is maintained.

Back 48

True
Because they lacked the understanding of the mechanics of inheritance.


(Chapter 1, p. 21)

Front 49

________ ________ is a model of inheritance that assumes the mother and father each contribute a hereditary substance that mixes, or "blends," to determine the characteristics of the offspring.

Back 49

Blending inheritance


(Chapter 1, p. 12)