Chapter 14- Habitat selection, Territoriality, and Migration

Question 1

Domestication of steelhead trout study

Answer 1

Researchers wanted to determine how quickly natural selection can act after a habitat changes. They bred pairs of wild caught trout and pairs of first generation hatchery raised trout. Offspring from all pairs were raised in the hatchery environment, and an mRNA molecular genetic analysis examined differences in the offspring of the WW and HH matings. They found heritable differences in gene expression in a large number of genes. Most differences in gene expression were associated with wound healing, immunity, and metabolism. HH offspring showed generally higher levels of gene expression. This makes sense because crowded environments like a hatchery can facilitate aggression and the spread of disease. The results suggest that evolution can act over only 2 generations

Question 2

Relationship between habitat and behavior

Answer 2

An animal’s habitat affects its behavior, but its behavior also affects its habitat

Question 3

Home range

Answer 3

Areas an animal passes through but does not spend much time in any specific one

Question 4

Territory

Answer 4

An area occupied and defended by an animal

Question 5

Abiotic factors

Answer 5

Factors like heat, availability of water, wind, refuge from danger, and availability of specific nutrients. Can impact habitat choice in combination with biotic factors

Question 6

Biotic factors

Answer 6

Factors like location of mates, food, predators, and parasites. Can impact habitat choice along with abiotic factors

Question 7

Migration

Answer 7

When animals make a shift in habitats, where they move over long distances. Some animals, like birds, migrate for a period of time and then return to their territory. Typically involves moving between a region where young are reared (breeding range) and nonbreeding region

Question 8

Habitat choice

Answer 8

How animals distribute themselves in space and time with respect to resources in their environment

Question 9

Ideal free distribution model

Answer 9

Addresses what behavioral rules animals use to distribute themselves between habitats. The model is used to predict the equilibrium frequency of individuals in different patches. Considers how many units of food each habitat provides per minute, along with the number of individuals in the population to determine how many individuals in the population should end up in each habitat

Question 10

What does the IFD model predict for the equilibrium distribution?

Answer 10

It predicts that the equilibrium distribution of individuals into patches should be the distribution at which, if any individual moved from the patch it was in, it would suffer a cost. At IFD equilibrium, and individual that moved from one habitat to the other would obtain fewer resources as a result of the move. This translates to individuals settling in habitats in proportion to the resources available in that patch.

Question 11

Mathematically, when is equilibrium reached in the IFD model?

Answer 11

Equilibrium is reached when R1N1=R2N2. R is the amount of resources and N is the number of individuals in the habitat

Question 12

IFD model of foraging in sticklebacks

Answer 12

The foraging behavior of fish was observed in two treatments. In one treatment, 5 times as much food was released at one feeder than the other. In the other treatment, the ratio was 2:1. The fish in both treatments distributed themselves under feeders in a ratio similar to the resource matching rule of the IFD model. This study did not examine foraging success, however.

Question 13

IFD model of foraging in mallards

Answer 13

The ducks were given food in patches of varying profitability. Profitability was manipulated by varying the number of pieces of food or the weight of each piece. When equal amounts of food were thrown into patches, ducks quickly distributed themselves in a 1:1 ratio. As predicted by the IFD model, when one patch had twice as much food as the other, the ducks distributed themselves in a 2:1 ratio

Question 14

Ideal despotic distribution model

Answer 14

In the IFD model in mallard ducks, some ducks were more aggressive, and therefore all individuals did not receive the same amount of food across patches. This model takes aggression into account

Question 15

2 ways evolution can act on behavioral traits to minimize exposure to disease

Answer 15

1. Avoidance of habitats that contain pathogens
2. Avoidance of individuals that are already ill

Question 16

How can individuals reduce the risk of infection from parasitic disease in their offspring?

Answer 16

They can produce offspring in habitats that have low parasite levels. Amphibians carry many parasitic pathogens and are able to distinguish between oviposition sites based on a wide variety of characteristics.

Question 17

Oviposition in treefrogs

Answer 17

Treefrogs base their decision on where to lay eggs based on the presence of a specific snail in their habitat. The snail is an intermediate host for a harmful parasite. Researchers wanted to determine whether treefrogs can distinguish between sites with the snails and whether they take into account the density of snails present. It was found that gray treefrogs favored ponds with no snails. They also were less likely to lay eggs in areas with a higher snail density.

Question 18

Which hormones impact spatial memory?

Answer 18

High levels of glucocorticoid hormones (stress hormones) interfere with spatial memory skills. Corticosterone is an example.

Question 19

Impact of corticosterone on spatial memory and habitat choice in rats

Answer 19

Rats were placed in a dark water tank with a platform that could serve as a resting place. When placed in the tank, rats swam around randomly and then discovered the platform- they got better at finding the platform with additional trials. Researchers hypothesized that a stress induced increase in corticosterone would impact the rats’ ability to find the platform. Rats were split into groups and received shocks at varying time intervals before water maze trials. The performance of the rats who received shocks a few minutes and a few hours before the trial was not impacted. The rats who received a shock 30 minutes before the trial did show impaired memory for the location of the platform, and they also had increased levels of corticosterone, suggesting the hormone has a memory inhibiting role

Question 20

In additional water trial experiments with rats, what happened when corticosterone production was inhibited?

Answer 20

Rats were injected with a drug called metyrapone, which blocks chemical signals in the adrenal glands and inhibits corticosterone production. With the drug, rats that were shocked before their trial did not show impaired memory and retained the ability to find the platform. In addition, rats who were injected with corticosterone but not shocked before the trial showed impaired memory

Question 21

Territoriality

Answer 21

The occupation and defense of a particular area. Territories provide their owners with access to food, mates, and shelter from predators. However, defending a territory can be costly in time and energy

Question 22

Group territoriality

Answer 22

Territories are sometimes defended by groups of individuals instead of a single individual or a family. This can result in dramatic between group interactions as one group tries to enlarge their territory by taking another group’s territory, similar to tribal raiding behavior in humans. This occurs in chimps as well

Question 23

Raiding behavior in chimpanzees

Answer 23

All male chimpanzee patrol groups travel into areas that border their territorial boundaries. These chimps do not emit the vocalizations that are typical of foraging behavior- they move cautiously and silently. Raids can result in killing a small number of the other group and capturing females. If two raiding groups encounter each other, they engage in hostile vocalizations and withdraw

Question 24

The role of learning in territory formation in anolis aeneus lizards

Answer 24

These lizards form territories early in life, and researchers examined how juveniles decided to stake out a territory. In this case, there was no effect of food availability in territoriality. However, safety from predators and appropriate temperatures were important in selecting a territory. Researchers hypothesized that lizards learned how to determine territory quality by watching other members of their species. If one individual is already using a territory, it must be suitable. This is called conspecific cuing

Question 25

Conspecific cuing model of territoriality

Answer 25

The idea that animals learn which territories are suitable by watching which territories are selected by other members of the species

Question 26

Conspecific cueing model of territoriality in lizards

Answer 26

Researchers examined whether a territory that had been occupied in the past but was now vacant would be attractive to lizards. When given a choice between a vacant territory and an occupied territory, the juvenile lizards chose the occupied territory once the territory owner was removed. This trend only occurred when the lizards were able to observe the territory being occupied

Question 27

Optimal skew theory

Answer 27

Studies the distribution of breeding within a group and whether there will be cooperation or conflict over reproductive activities. Sometimes it’s in the best interests of the family for an individual to stay at home and not breed in order to help out with siblings

Question 28

Parent-offspring conflict over breeding opportunities in white fronted bee eaters

Answer 28

Young male white-fronted bee eaters often remain on their natal territory and help their parents with raising their siblings. There is no conflict between the young male and their parents if breeding opportunities are rare. However, there may be conflict if the male has the opportunity to mate and leave home. Parents receive a greater benefit in fitness if their son stays than if the son leaves because parents are more related to their offspring than their grand offspring. A male is equally related to his siblings and offspring, so there is no incentive for a male to resist his parents’ attempt to suppress his breeding. There is more resistance if an individual attempts to stop other kin or non kin from breeding

Question 29

Nest complexity and cerebellar foliation

Answer 29

The amount of folding the in cerebellum is positively correlated with nest complexity in birds

Question 30

Obligatory migration

Answer 30

Annual migration that occurs like clockwork

Question 31

Irruptive migration

Answer 31

Migration that occurs only when conditions are poor

Question 32

Migration patterns in cuckoos

Answer 32

In the fall, cuckoos living in the UK migrate south to central Africa for the winter. Researchers used trackers to determine that cuckoos used 2 different migratory routes- a southwest route via Spain or a southeast route via Italy. Both routes ended in the same location and birds were consistent in using the same path every year. Although the southwest route was shorter, the mortality rate was higher. This may be due to severe drought and wildfires near Spain. There is a negative correlation between population size in a UK population and the proportion of birds that migrated using the southwest route

Question 33

Navigation techniques of monarch butterflies

Answer 33

Monarch butterflies use the position of the sun to help them navigate as they migrate south. Researchers conducted a clock shift experiment where they experimentally manipulated the amount of daylight and darkness the animals were exposed to to make it seem like a different time of year. Once the butterflies had been clock shifted back six hours, they flew west when released rather than south, which is the direction they usually fly when migrating. The clock shift caused the butterflies to misinterpret the information that the sun was conveying about direction

Question 34

Indigo buntings and star navigation

Answer 34

Most passerine birds migrate at night, when there is no sun to use as a cue. Researchers placed buntings in a funnel shaped test cage that could record the orientation patterns of the bunting’s flight. When the cages were placed under a starlit sky, the buntings oriented their flight attempts toward the south in September and October and toward the north in April and May, which is the direction they would normally migrate. These patterns disappeared on cloudy nights when stars weren’t visible, which suggests that stars play a role in navigation. Results were similar in a planetarium when the North Star was artificially shifted

Question 35

Earth’s magnetic field and bobolink migration

Answer 35

Birds were brought to a planetarium, which projected star patterns that matched the autumn sky in the Northern Hemisphere. When the birds were given correct visual cues, they oriented south. The magnetic polarity the birds experienced was also manipulated. When the visual cues and magnetic polarity were consistent with each other, the birds oriented in the correct direction. When visual cues were correct but magnetic polarity reversed so north was the opposite direction, the birds headed toward the magnetic south. This indicates that magnetic cues are used for bobolink round trip migration

Question 36

How are bobolinks able to sense changes in magnetic polarity?

Answer 36

Researchers found high levels of an iron rich, magnetically sensitive substances in the bobolinks during autopsies. The substance was found around the olfactory nerves and the bristles that project into the nasal cavity, as well as in the tissue between the nasal cavity and the eyes

Question 37

Why do animals increase rates of foraging prior to migration?

Answer 37

To increase levels of body fat, as long migrations require a lot of energy. In birds, basal metabolic rate is significantly higher in migrating species

Question 38

Basal metabolic rate and migration in birds

Answer 38

Species that live in colder environments tend to have high BMRs, and species that migrate tend to be found in cold environments. Therefore, the relationship between BMR and migration could just be due to the fact that migratory species tend to live in colder places. An analysis found that BMR was more tightly correlated with environmental temperature than the tendency to migrate. Natural selection favors both migration and higher BMR in bird species and cold environments, causing the association between the variables

Question 39

Why does migration make animals more susceptible to disease?

Answer 39

The energy used during long migration can reduce immune responsiveness, making animals more susceptible to disease. Animals also face new parasites and diseases in the new environment they migrate to, since the new environment is very different from their past environment.

Question 40

Migration and immune function in birds

Answer 40

Researchers hypothesized that migratory birds should invest more heavily in immune function compared with related resident relatives. They compared 2 immune defense organs- the spleen and a lymphoid organ called the bursa of Fabricus. The bursa of Fabricus and the spleen was larger in most birds from migratory species. This suggests selection on the immune system of migratory species

Question 41

Evolutionary precursor model of migration

Answer 41

States that migration will be associated with species that live in open or edge habitats rather than species that live in forests. This is because open and edge habitats exhibit greater seasonal variation in food resources than do forest habitats, and this variation might select for migration in the birds from open and edge habitats

Question 42

Migratory behavior of Motacillidae birds

Answer 42

Researchers categorized the migratory behavior of 49 species of birds as either migratory or sedentary, and their habitat as either open/edge or forest. Phylogenetic evidence did not support the evolutionary precursor model- there was no association between migration and habitat in terms of open/edge vs forest. The analysis suggests that Motacillidae’s ancestral state of migration was sedentary and the ancestral habitat was likely open/edge. In addition, species that lived at high altitudes were also more likely to migrate than those that lived at lower altitudes

Question 43

Density-dependent habitat selection

Answer 43

One factor in making a habitat selection, reflects intraspecies competition

Question 44

Benefits of territoriality

Answer 44

One of the primary benefits of territorial behavior is the ability to use the resources on a territory without interference from others. When the benefits are greater than the costs, territory defense will be favored by natural selection

Question 45

American redstart competition for territories

Answer 45

The American redstart competes for territories during the nonbreeding season on its wintering grounds in Caribbean and Central America. Heavier males in mangrove habitat attack intruding females and younger males, forcing
them into second-rate habitats. Redstarts living in mangroves retained their weight over the winter, whereas those in inferior scrub habitat generally lost weight. This illustrates the costs of territoriality. Probably because they
have more energy reserves, male territory holders in mangroves leave their wintering grounds for their breeding sites sooner- this provides a fitness benefit

Question 46

Dispersal

Answer 46

The one-way, permanent movement from the birthplace to somewhere else. Some species juveniles display sex-biased
dispersal, in which one sex disperses farther than the other. This occurs in ground squirrels, with males dispersing farther than females

Question 47

Passive dispersal

Answer 47

Occurs with marine animals and small insects that produce large amounts of small offspring

Question 48

Costs of dispersal (4)

Answer 48

1. Energy
2. Time
3. Predators
4. Opportunity costs- reduced fitness if an individual selects a poor habitat

Question 49

Tropical origins hypothesis of migration in birds

Answer 49

Migration evolved through a geographic shift from the
tropics to the temperate breeding grounds to take advantage of the rich bounty of food resources for reproduction

Question 50

Temperate origins hypothesis of migration in birds

Answer 50

Migration evolved through a shift toward the tropical
wintering grounds from the temperate breeding grounds
to take advantage of the milder climate during the
nonbreeding season.

Question 51

Proximate analysis

Answer 51

What are the immediate causes for the behavior?
Hormones, neurotransmitters, fear response are examples of causes. This analysis occurs at the level of the animal. Includes mechanistic and developmental questions.

Question 52

Ultimate analysis

Answer 52

Focuses on the evolutionary forces that have shaped this behavior over time. Occurs at the level of the species. Includes survival value and evolutionary history questions.

Question 53

4 types of questions about how to study behavior

Answer 53

1. Mechanistic
2. Developmental
3. Survival value
4. Evolutionary history

Question 54

Mechanistic questions

Answer 54

Asks what stimuli causes this behavior. What changes are occurring in the body in response to this stimuli? Includes changes in hormones, neurotransmitters, and brain connectivity.

Question 55

Developmental questions

Answer 55

Asks if this behavior is the same as the organism ages. Is it seen at all ages, or to the same extent at all ages? Sexual behavior is an example of a behavior that generally develops after puberty, later in an animal’s lifespan.

Question 56

Survival value questions

Answer 56

Is this behavior necessary for survival, and does it increase the likelihood of successful mating? For peacocks, males have large, colorful tails. This puts the males at greater risk because they are more likely to be seen by predators. However, the tail is necessary for reproduction, so it does have survival value

Question 57

Evolutionary history questions

Answer 57

How does the behavior change from the viewpoint of phylogeny? Phylogenetic trees are used to study this- at what point in evolutionary history was this trait added?

Question 58

Artificial selection

Answer 58

When humans want to increase the probability of a trait being expressed in the species. The species undergoes an artificial breeding program so this trait will occur more frequently. In Darwin’s The Origin of Species he described how pigeons were able to be bred artificially to increase the frequency of certain traits, like with breeding homing pigeons. Also occurs with plants and many other animals

Question 59

Natural selection

Answer 59

The evolutionary process where traits increase in frequency over time if they give an individual a reproductive advantage. Darwin came up with this theory even before Mendel’s work on genetics.

Question 60

Pavlovian/classical conditioning

Answer 60

Stimuli are paired. One is neutral (conditioned), the other is designed to elicit a response (unconditioned stimulus). Eventually the animal will respond to the neutral stimulus like it would the conditioned stimulus. This response to the conditioned stimulus is called the conditioned response

Question 61

Conditioned stimulus

Answer 61

Classical conditioning- a stimulus that initially fails to elicit a particular response but comes to do so once it’s associated with the second (unconditioned) stimulus. For example, a blue stick being paired with cat odor will eventually cause a fear response in rats.

Question 62

Unconditioned stimulus

Answer 62

A stimulus that elicits a response in the absence of training, like fear.

Question 63

Second order conditioning

Answer 63

Once a conditioned response has been learned by pairing the unconditioned stimulus and conditioned stimulus 1, a new stimulus is presented before CS1. If the new stimulus eventually elicits the conditioned response, the new stimulus becomes a conditioned stimulus (CS2).

Question 64

Operant/instrumental conditioning

Answer 64

Occurs when the response that is made by an animal is reinforced (increased) by the presentation of a reward or the termination of an aversive stimulus. Or the response can be suppressed (decreased) by the presentation of aversive stimulus or termination of reward.

Question 65

Cultural transmission

Answer 65

A system of information transfer that affects an individual’s phenotype by means of either teaching or some form of social learning. Can occur within or between generations.

Question 66

3 modes of cultural transmission

Answer 66

1. Vertical
2. Oblique
3. Horizontal

Question 67

Vertical cultural transmission

Answer 67

Occurs when information is transmitted across generations from parents to offspring. It can take place through teaching or social learning. In some finch species, vertical transmission occurs when males learn the song that they will sing from their fathers, and females develop song preferences in mates based on the songs their father sang

Question 68

Oblique cultural transmission

Answer 68

The transfer of information across generations, but not parent/offspring interactions- young animals get information from other adults. This is more common in systems where there is no parental care.

Question 69

Horizontal cultural transmission

Answer 69

Involves transmission between peers- occurs in young individuals as well as adults

Question 70

Social learning

Answer 70

The process of learning by watching others

Question 71

Teaching

Answer 71

A form of cultural transmission in which the teacher imparts some information to a student faster than the student could learn it on their own. There is one individual serving as an instructor and one acting as a student. A teacher must provide an immediate benefit to students but not to themselves

Question 72

Kin selection theory

Answer 72

Predicts that individuals shouldn’t be aggressive to kin like siblings. However, in situations where resources are limited and the siblings have to compete, each sibling wants those resources for themselves