Lecture 14: Behavior

Question 1

The mechanisms and ontogeny of a behavior ask ____

Answer 1

How a behavior happens

Also called casual or proximate

Question 2

The phylogeny and fitness of a behavior ask _____________________

Answer 2

Why it evolved

Also called functional or ultimate

Question 3

Female estrus in lions is __________________ meaning…

Answer 3

synchronous meaning the mechanism is hormonal and they don’t consciously realize it is happening

Ex. When one lion gets pregnant, many others of the herd will also get pregnant because they have a hormonal response to one another

Question 4

When evaluating animal behavior,
HOW is asking…
WHY is asking…

Answer 4

How asks what mechanisms are involved

Why is asking how those mechanisms evolved

Question 5

What is one of the hypotheses for why male lions will kill other cubs in the pack?

Answer 5

The male needs reproductive benefits. He wants the female to be caring for his offspring so he kills the cub that isn’t his to mate with the female so she will instead be caring for his cubs.

Question 6

What are casual explanations for behavior?

Answer 6

How a behavior happens
AKA proximate or mechanistic

Ex: Observation: Female lions are synchronous in estrus and the casual explanation for this is chemical cues

Question 7

What are functional explanations for behavior?

Answer 7

Why a behavior has evolved
AKA Ultimate

Ex. Observation: Female lions are synchronous in estrus and the functional explanation for this is better cub survival when raised/protected in a group vs alone

Question 8

Casual and Functional explanations of behavior are _____________, not _____________

Answer 8

Complementary, not competing

Question 9

Is the “why” of a behavior important from the perspective of stellar evolution?

Answer 9

No, it is only important in organic evolution

Question 10

What are the similarities between organic and stellar evolution using the five points of Darwin’s theory?

Answer 10

Same
1) Universe is ancient and constantly changing
2) The ongoing change is steady and gradual
4) New stars are always being formed

Different
3) Common descent (not true for stars)
5) Natural selection (not true for stars)

Question 11

Behavioral Ecology

Answer 11

Focuses on the why of natural behavior

Answers the ? of why a behavior is selected for by natural or sexual selection

Question 12

Sexual Selection

Answer 12

Traits that evolve because they increase access to mates

Usually evolve in males

Involve weaponry, size, color, calls, etc

Two situations could occur that lead to development of certain sexual traits
A) A need for force (weaponry)
B) A need for charm (color, calls, etc)

Question 13

Explain a sexually selected trait in elephant seals

Answer 13

Size
Bigger size makes it easier to fight off other males to defend your nest, resources, etc

Pups could be killed in the hatching grounds in the years after they are being born because the large males will “run over them”. In this case, they don’t care about those pups, only about increasing their ability to father a newer generation of pups

Question 14

If a female does not select a mate based on the male himself, what might she choose a mate because of?

Answer 14

The habitat, resources, or gifts he can provide

Question 15

Male trait values (sexually selected ones) will increase until…

Answer 15

those traits are opposed by natural selection

AKA the mating advantage no longer outweighs the survival disadvantage

Question 16

What happens to a sexually selected trait when natural selection acts against it?

Answer 16

The trait will “reverse” and the process will repeat again with the trait getting less advantageous –> more advantageous until natural selection acts against it once again

Question 17

What are the things on a “natural selection checklist”

Answer 17

Variation
Inheritance
Fitness effects

Question 18

Why does a male red-backed spider allow himself to be consumed in the act of mating?

Answer 18

He has already fathered offspring and is satisfied from a natural selection perspective

Question 19

What determines the degree of intensity of natural selection?

Answer 19

The relationship between advantages and disadvantages

Question 20

What is the selfish herd effect?

Answer 20

Each individual seeks safety from predators by hiding themselves within a group

Question 21

What are the foraging benefits and why did this trait evolve?

Answer 21

Group hunting enables some predators to capture prey too large or dangerous to handle alone

This trait evolved because it is advantageous (does not mean it doesn’t have costs, just that the benefits outweigh them)

Question 22

What is one of the advantages of group foraging?

Answer 22

Safety is higher in groups, if they are better able to spot predators

Question 23

Altruism

Answer 23

Any behavior that benefits an individual (or group) at the cost of one animal

Ex. A group goes out to hunt while one animal watches for predators–more likely to be preyed on

Question 24

For something to evoke, the _______________ must outweigh the _________________

Answer 24

advantages must outweigh he disadvantages
(usually a reproductive benefit)

Question 25

How do relatives affect altruistic behavior?

Answer 25

Organisms are more likely to put themselves at risk for relatives because relatives are more likely to carry the same alleles

Question 26

Alleles that promote altruism are favored by natural selection if...

Answer 26

they enhance the fitness (survival or reproduction) of relatives by an amount sufficient to compensate for the cost of the altruist

Question 27

Hamilton's rule for the evolution of altruism states that...

Answer 27

b=benefit to the recipient c=cost to the altruist r=coefficient of relatedness Altruism evolves if c < br If cost is less than the # of extra alleles that go to the next generation

Question 28

Eusociality

Answer 28

The highest level of social organization It is characterized by a reproductive division where a few individuals reproduce while the others are sterile workers that cooperate to raise the offspring

Question 29

What things define eusociality?

Answer 29

1) Cooperative brood care 2) Overlapping generations within a group 3) Division of labor into reproductive and non-reproductive groups (often with specialized sub groups)

Question 30

What was the idea from O. Wilson's book?

Answer 30

The species with the most advanced organization system dominate the planet Vertebrates: Humans Invertebrates: Ants

Question 31

Why are ants such a highly developed organizational system?

Answer 31

They split up into reproductive (Queen) and workers (everyone else) and have highly efficient systems that allow them to reproduce quickly and spread nests far and wide while (sometimes) taking over local ecosystems

Question 32

From an anti-predator's POV, what are the benefits (4) for living in groups?

Question 33

From a foraging POV, what are the benefits (2) for living in groups?

Answer 33

1) Better food finding (information centers) 2) Better food capture (group hunting)