Midterm 1 - behaviour, evolution, hypotheses Flashcards
1
Q
what is a behaviour?
A
A behaviour is any involuntary or voluntary response to an external or internal stimulus
2
Q
Do behaviours have to be voluntary?
A
No, there are involuntary behaviours too, for example, breathing.
3
Q
What is an example of an internal stimulus that can create a behaviour?
A
hormones
4
Q
True or false. Seeing a predator is an example of an external stimulus, that will trigger a behaviour in the animal
A
true
5
Q
True or false. Exhibiting behaviour is a property, a characteristic, of life. All living things exhibit behaviour
A
True
6
Q
The father of ethology was __________?
A
Nikolaas Tinbergen
7
Q
What are the four ways Nikolaas Tinbergen said you could ask questions about behaviour?
A
- What are the physiological mechanisms behind this behaviour? (intrinsic mechanisms)
- How does the behaviour develop in the animal (ontogeny)?
- What is the adaptive value of the behaviour? (adaptive value)
- How did the behaviour originate and be modified over evolutionary time? (phylogeny)
8
Q
Describe what a proximate cause for behaviour is.
A
Proximate causes explain how a behaviour works (physiologically) or is developed in the life of the individual (ontogeny). Proximate causes explain the HOW of a behaviour.
9
Q
Describe what an ultimate cause for behaviour is.
A
Ultimate causes explain why behaviours exist. What they’re adaptive value is, why they originated, how they have evolved… Ultimate causes explain the WHY of a behaviour.
10
Q
What is an ethogram?
A
A list or description of all the behaviours you observe in an animal of a certain species.
11
Q
What is a time budget?
A
A time budget is you basically noting down how much time an animal spends doing a certain behaviour
12
Q
What is an independent variable?
A
A variable that is not affected by other variables in the experiment. It is usually what is being manipulated by the experimenter, or the variable that varies between groups (independently of other variables).
13
Q
What is a dependent variable?
A
A variable that is affected by the independent variable, and is what we are measuring in the experiment.
14
Q
What is a categorical/discrete variable?
A
Any variable that can only take a set or limited number of values - for example, location, plot #, sex etc.
15
Q
What is a continuous variable?
A
Any variable that can take any value between a maximum and minimum - e.g. population size, elevation, age, height, weight etc.
16
Q
What kind of variables would you do a linear regression on?
A
Both variables are continuous variables
17
Q
What kind of variables would you do a t-test on?
A
X categorical, y continuous - only two groups
18
Q
What kind of variables would you do an ANOVA on?
A
X categorical, y continuous - 2+ groups
19
Q
What kind of variables would you do a Chi-square test on?
A
Both X and Y are categorical variables
20
Q
What kind of variables would you do a Logistic regression on?
A
Y is a categorical BINARY variable, x is a continuous variable.
Basically opposite of ANOVA, where the x is the categorical variable, but remember that the categorical y variable here is binary.
21
Q
Would an ANOVA tell you which group mean is different? What test should you use to figure that out?
A
no, will need a Tukey-Kramer test
22
Q
A p-value is significant when it is less than _______. It represents the probability of getting the data you have by chance alone.
A
0.05 (5%).
It means there’s a 5% chance you got the data by chance alone.
23
Q
what is estrous?
A
Estrous is the phase in a female’s reproductive cycle in which the female is sexually receptive to the male
24
Q
what is monoestrous/monoestrum mean?
A
Monoestrum means that there is one estrous phase per breeding season
25
compare and contrast the social system of wolves and lions?
Wolves:
- males and females in the pack are related
- breeding pairs can choose to leave the pack
Lions:
- Females are related, males likely from a different pride
- Males must leave their pride and take over a new one
26
Compare the Reproductive System and Behaviours of Wolves vs. Lions:
Wolves:
- Monoestrous females
- Monogamous breeding - mate pairs
- Seasonal breeding
- Both males and females involved with parental care
- Only the breeding pair/dominant pair breeds. Subordinates rarely do.
- Female wolves go through pseudopregnancy
- Wolves go through copulatory tie
Lions:
- Polyestrous females
- Breeding not seasonal
- Polygamy (males mate with all females)
- No pseudopregnancy
- Lions don't have copulatory ties
- Male lions may kill cubs of other males, or females may abort cubs if a new male takes over.
27
How do you know an animal is monogamous or polygamous? What is one physical feature to look out for?
If the species are sexually dimorphic they are likely polygamous.
28
What is the proximate explanation of monoestrum?
Proximate = Mechanistic (physiology) explanation -
an extended luteal phase due to a long-lived corpus luteum (CL), means the amount of progesterone is high for longer in the blood of female wolves. Progesterone prevents ovulation
29
What is the ultimate explanation of monoestrum?
Adaptive value explanation-
2) Breeding once, when it is optimal, will ensure cub survival and waste less energy, because cubs may die in winter months when food is scarce.
3) Polyestrous lifestyle would create conflict in the pack because it would promote breeding between subordinates. In class we talked about how this is unlikely to be the case, because many canid species hae evolved monoestrum, but they do not live in social groups like wolves do, so the idea that monoestrum is connected to group cohesiveness doesn't make sense for them. Option 2 is what Leticia liked best.
30
What is the proximate explanation of male parental care?
Mechanistic / physiological explanation:
High amounts of prolactin in males is released around the same time pups are born, and many studies have linked this hormone to parental care behaviours.
31
What is the ultimate explanation of male parental care?
Adaptive value:
Greater chance for pups to survive, and therefore greater success of the pack, and passing of the genes of the mating pair, which are the genes in the subordinates too.
32
What is the proximate explanation of female alloparental (not your child) care?
Mechanistic / physiological explanation:
Extended luteal phase (i.e. a pseudopregancy) due to a long-lived CL means that LH levels are high in the blood of females for a long time, and this along with prolactin gives female wolves maternal instincts. This is because pseudopregnancy results in an endocrine activity similar to pregnancy.
33
What is the ultimate explanation of female alloparental (not your child) care?
Greater chance for pups to survive, and therefore greater success of the pack, and passing of the genes of the mating pair, which are the genes in the subordinates too.
34
What are adaptations?
Heritable traits that improve the chances of an organism to survive and/or reproduce
35
Can some behaviours that we see not be adaptive (two reasons)?
Yes.
1. The behaviour could have initially been adaptive but now isn't after a change in environment
2. Some behaviours didn't evolve because they had adaptive value, but rather due to mutation or drift
36
What mechanism leads to the evolution of adaptations?
natural selection
37
What is natural selection?
A mechanism of evolution by which organisms descend with modification from their ancestors.
38
Evolution by natural selection occurs when four conditions are met. These four conditions are referred to as _________________
Darwin’s Four Postulates
39
Name Darwin’s Four Postulates
1. There must be VARIATION in a trait in the population
2. Some traits result in better survival/reproduction than others
3. The trait must be heritable
4. There must be a turnover of individuals in a population that must die, so that a more adaptive generation can take over.
40
What is phenotypic plasticity? Give an example
The ability of a genotype to have a different phenotype depending on the environment for example Daphnia from high predation sites won't go up towards light when the area has high predation, but will if the area has fewer predators.
41
True or false. The ability to learn is considered a heritable trait
true
42
True or false. The ability to learn is governed by both genetics and the environment.
True. For example, in one study, identical twins that grew up in different environments did a learning task differently compared to identical twins living in the same environments.
43
What is "heritability"?
Heritability is the measure of the proportion of phenotypic variation in a population that has been inherited from genes from parents.
44
What symbol represents heritability?
h^2
45
What is a parent-offspring regression plot?
A regression plot with mean trait value of the parents on the x-axis, and mean trait value of the offspring on the y-axis
46
One way to measure heritability, h^2, is with a parent-offspring regression plot. Explain how.
The slope is the heritability of the trait, h^2
47
In a parent-offspring regression plot, what does it mean...
a) if the slope is 0
b) if the slope is 1
a) We cannot predict what the offspring will look like based on the parents.
b) We can predict 100% what the offspring will look like based on what the parents looked like.
48
True or false, another way of measuring heritability is by using an equation with the response to selection, R, and the selection differential, S.
true
49
What is the equation for the response to selection, and state what each variable in the equation stands for.
R = (h^2) S
R is response to selection
h^2 is the heritability of the trait of interest
S is the selection differential
50
What is the equation for the selection differential, S?
In the SAME GENERATION:
Take the mean of the individuals favoured by selection in the population, Xs, and subtract it with the mean of the population Xp.
S = Xs - Xp
51
If you do not have the value for h^2 or S, what equation would you use to find R? You can't use R = (h^2) S
R is also equal to the difference between the mean of the NEXT generation in the offspring Xr, and the mean of the PREVIOUS parental population, Xp
R = Xr - Xp
52
How would you calculate heritability using population variances?
h^2 = Va / (Va + Vd + Ve)
53
Does a heritability, h^2, of 0 mean the trait is not heritable?
No, the trait can still have a genetic basis, but we simply cannot predict what the phenotype of the offspring will be based on the phenotype of the parents.
So there would be no additive effects, but the trait could have a genetic basis, but the phenotype we see could be controlled by something like environmental factors.
54
Can estimates of heritability that you made about one population be applied to other populations?
No. Heritability estimates are taking into account the environmental factors that the population is in, and these environmental factors may differ in different populations, so their heritability estimates could be entirely different.
55
Why use heritability if it has so many caveats?
It helps us predict whether a specific population is responsive to natural selection.
56
Other than natural selection, what is another mechanism by which behaviours can evolve?
genetic drift
57
The effects of genetic drift are stronger than natural selection when populations are ________
small.
58
Does genetic drift happen in populations of infinite size?
no.
59
Drift has a strong effect on the evolution of _____ alleles.
Neutral
60
What is non-adaptive evolution?
When genetic drift results in the fixation of maladaptive alleles for behaviour
or
when genetic drift results in the loss of FAVOURABLE adaptive alleles for behaviour.
61
What are the four limitations of natural selection?
1. It is constrained by evolutionary history
2. Not every trait is adaptive
3. There may be tradeoffs associated with adaptive traits
4. Natural selection cannot foresee the future, what we see are the results of environmental conditions in the immediate past.
62
Are organisms designed to be ideal?
No. Natural selection is constrained by evolutionary history, so it has to work around ancestral constraints instead of creating a newer more efficient solution to a problem
63
Natural selection cannot foresee the future. Its results portray environmental conditions that were there in the immediate past. This is referred to as the “__________________”
Red Queen's Hypothesis - The environment changes first, and organism changes lag behind.
64
What are four reasons for why a trait may not be adaptive?
1. genetic drift has selected for maladaptive alleles or lost adaptive alleles
2. The trait might exist as a consequence of chemistry and physics - for example, the colour of hemoglobin being red isn't adaptive, it's just chemistry.
3. There could be multiple adaptive peaks, all equal in fitness
4. The gene could have been hitchhiking. Genes that are selected for can't be isolated and bring along flanking genes with them.
65
Whenever you make hypotheses, you make at least two. A ______ and an ________ hypothesis
A null and an alternative hypothesis.
66
What is an observational study?
A study in which the researcher simply observes a sample population in their natural surroundings, and collects data from them.
67
Explain the findings of the garter snake thermoregulation study, also explain what kind of study this was?
Explain the null, the alternative hypothesis, and the results.
This is an observational study.
Garter snakes like to stay under rocks, but the rock thickness they choose has an effect on their body temperature.
Thin rocks would make the snake too hot in the day and too cold at night. Thick rocks would make the snakes too cold both in day and night. Rocks of medium size let the snakes be in optimum temperature in both day and night.
Null: garter snakes have no preference for rock thickness
Alternate: garter snakes prefer rocks that are medium-sized because it allows for optimal thermoregulation.
Results: the alternative hypothesis was supported. Garter snakes would overwhelmingly choose medium-sized rocks.
68
Explain the crow nutcracker experiment. Say the null, alternative, what kind of experiment it was, and the results.
Null: crows were not using cars to crack nuts, but rather dropping them on hard roads to make them crack and the cars running over the nuts is a coincidence
Alternative: crows were purposefully using cars to crack nuts by putting them in their paths
Kind of experiment: observational
Results: If crows were using cars, they would arrive and drop the nut more often when the road had cars than didn't. Also do the relinquish behaviour more often. That was not the case. Crows were not using cars to crack nuts.
69
What is a manipulative experiment?
An experiment in which the researcher can manipulate the independent variable, controlling for other variables, and then record the effect on the dependent variable.
70
Explain the Black-headed gull eggshell removal study
Give the null, the alternative hypotheses, type of study and results.
Null: black-headed gull nests are equally susceptible to predation regardless of whether they have a nest with regular white egg shells or a nest with painted camouflages egg shells
Alternate: Nests with the painted camouflaged eggs were less predated on.
Type of study: manipulative
Results: the alternative hypothesis was supported.
71
Explain the Tephritid fly mimicry study.
There is a null, two alternative hypotheses, for this study, what were they?
What kind of study is this?
What were the results?
Tephritid flies have colourings on the wings and a waving behaviour that make them resemble their predators, the jumping spiders. Does this make them less likely to be eaten by the jumping spiders?
Null: The markings and display behaviour have no effect on reducing predation on the flies
Alternative 1: the marking and display behaviour reduce predation by the jumping spiders
Alternative 2: the marking and display behaviour reduce predation in other predators of the flies.
Design: they had five treatments:
(1) The Tephritid flies, untouched
(2) Regular flies without the markings (different species of fly)
(3) Tephritid flies with their wings cut off and regular fly wings glued on
(4) Tephritid flies with their wings cut off, and their wings glued back on
(5) A regular fly with Tephritid fly wings attached to them
Result: spider predation and/or attack was less frequent for flies in the (1) and (4) treatments.
This is a manipulative experiment.
72
What are comparative studies?
Studies that compare phylogenetic characteristics and relationships.
73
Describe the Bat testes size and social group study.
describe the null, the alternative hypotheses, the type of study this is, and the results.
Type of study: comparative study
Null: The trait "testes size" is not correlated with the trait "social groups"
Alternative: Testes size is positively correlated to group size because both are proxies for a greater sperm competition.
results: alternative was supported. Bats with larger testes had greater group sizes. Makes sense because a larger group size and larger testes size are both proxies for a greater sperm competition.
74
True or false. Independent phylogenetic evolution of a trait is important. If two species derived a trait from the same MRCA, that would then be just one replicate, not two.
True
75
Comparative studies check for phylogenetic dependence (traits coming from the same MRCA) using _________?
Phylogenetic Independent Contrasts
Remember it as "PIC" if you need to
76
How do you do phylogenetic independent contrasts?
You take species of the same clade and make a paired data point. Then you take the one from the pair closest to zero and move its value to zero. What’s left is the other half of the pair, and that becomes one data point. When doing this, you might have to use extinct taxa (e.g. S, T, U, R)
It’s hard to know what size their testes were. So what they do for that is they take the mean trait value (in this case, testes and group size) of all the descendants of that extinct taxon (for example, M and N for the extinct taxon S), and use the mean.
