Lecture 2 Evolutionary Approach

Question 1

What are the 5 assumptions of natural selection?

Answer 1

1. variation among individuals
2. variation is heritable
3. organisms produce more offspring than can be supported by available resources
4. competition occurs among individuals
5. organisms that can reproduce are favored

Question 2

What are the 4 levels of selection?

Answer 2

1. gene 2. individual 3. group (interdemic) 4. species

Question 3

What is GENE selection?

Answer 3

selection may favor particular gene; natural selection operates upon the phenotypic expression of a gene

Question 4

What is INDIVIDUAL selection?

Answer 4

selection favors individual; individuals with a combo of well adapted genes are most likely to survive and reproduce

Question 5

What is GROUP (interdemic) selection?

Answer 5

selection favors group rather than individual “for the good of the species”; to avoid overpopulation, groups which limit their reproduction or commit suicide have a selective advantage over groups whose populations increase then crash ie. honey bees sting an intruder and die to protect the group

Question 6

What is a major problem with group selection?

Answer 6

individuals may cheat; in nature cheaters always prosper

Question 7

What is an explanation for self sacrificing or altruistic behavior?

Answer 7

altruistic behavior is performed by individuals for the benefit of the closely related kin; may increase its genetic fitness by performing behavioral act that decreases its own fitness by increases fitness of closely related relatives; altruistic behavior is actually selfish

Question 8

What is SPECIES selection?

Answer 8

selective distinction of species; removes species within a group of species rather than genes within a species; thought to be a driving force in macroevolution

Question 9

Which level of selection has strongest evolutionary effect?

Answer 9

selection acting on differences among individuals.

Question 10

What are the two factors that cause behavior?

Answer 10

1. ultimate 2. proximate

Question 11

The variable that determines the value of the measured variables is the ________?

Answer 11

independent variable

Question 12

What kind of factors deal with immediate mechanisms of behavior?

Answer 12

Proximate factors

Question 13

What are ultimate factors?

Answer 13

long term evolutionary causes of behavior; resources-based: food, water, territory, mating, shelter, etc; ultimate factors answer “why” questions about behavior

Question 14

What are proximate factors?

Answer 14

immediate conditions or mechanisms that cause behavior; environmentally-based photoperiod, rainfall, olfaction, etc., answer “how” questions about behavior

Question 15

Why do temperate species of birds in North America fly southward during autumn and northward during spring?

Answer 15

Birds migrate in search of resources.

• ultimate factors: food, less competition during breeding season
• proximate factors: increasing photoperiod triggers hormones, which cause birds to migrate north/south

Question 16

What is an ethogram?

Answer 16

inventory of behaviors performed by a species of animal (time budget); allows for hypotheses to be tested to explain similarities or differences between species

Question 17

What is the experimental method?

Answer 17

one of more variables are controlled under natural or lab conditions

Question 18

What is an independent variable?

Answer 18

factor that defines condition or treatment of a group in an experiment

Question 19

What is a dependent variable?

Answer 19

behavior that is observed or measured

Question 20

What is the control group?

Answer 20

an unmanipulated set of test subjects

Question 21

What is an experimental group?

Answer 21

a manipulated set of test subjects; often more than 1 experimental group in a study

Question 22

What is a null hypothesis?

Answer 22

No difference between groups being tested; either accepted or rejected; best evaluated in terms of probability with inferential statistical tests

Question 23

How do we test hypotheses?

Answer 23

find a satisfactory explanation for a particular behavior by using scientific method

Question 24

What is observer behavior?

Answer 24

When a male lion takes over a pride and kills all of its infants… ask a question.. form a hypothesis…test it

Question 25

What is the sexual competition hypothesis?

Answer 25

scope is to get your genes into the next generation; best explains infanticide

Question 26

What is the cannibalism hypothesis?

Answer 26

killer males obtain high quality meals by killing infants

Question 27

What is the social pathology hypothesis?

Answer 27

human interference causes stress on the killer male lion and affects his actions

Question 28

What is the aggression hypothesis?

Answer 28

killer males are extremely aggressive and dominant; evidence is weak to support this over sexual competition hypothesis.

Question 29

True or False: Science must accept that there is an absolute certainty in many of our conclusions.

Answer 29

False; old ideas are continually being replaced and modified by new ones.