Exam prep

Question 1

What are Tinbergen’s four questions?

Answer 1

1. Ontogeny - how does X develop? (e.g. in Developmental Psych)
2. Mechanism/Causation - how is X triggered? (e.g., neuroscience, learning)
3. Phylogeny - evolutionary history (e.g. animal cognition)
4. Adaptation/function - what is the survival value? (e.g. evolutionary psychology)

Question 2

Define proximate explanations vs. ultimate explanations. Which is the focus of evo psych?

Answer 2

Proximate = How does X function?
Ultimate = Why did X evolve the way it did? (U is the focus of evo psych)

Question 3

What is the dynamic question of proximate and of ultimate explanations? What does dynamic refer to?

Answer 3

Dynamic = past explains present
Proximate - ontogeny
Ultimate - phylogeny

Question 4

What is the static question of proximate and of ultimate explanations? What does static refer to?

Answer 4

Static = explains current form
Proximate - mechanism
Ultimate - Function

Question 5

Define artificial breeding, a.k.a. selective breeding

Answer 5

selection in which humans choose which organisms reproduce based on desired traits

Question 6

Define Character

Answer 6

A structure or feature found in a group of organisms (e.g. the
vertebrate eye, a courtship display)

Question 7

Define character state

Answer 7

An attribute or value of a character. For example the character “eye colour” may have the states “red” and “blue”, and a display may
be present or absent

Question 8

Define comparative method

Answer 8

Comparing character states for multiple species or populations in order to understand relationships or trends among these
characters and how they have influenced patterns of evolution. Such correlations are often used to test adaptive hypotheses.

Question 9

Define convergence

Answer 9

A type of homoplasy where two or more taxa independently evolve the same character state from different ancestral states. (E.g. eyes in humans and octopus.)

Question 10

Define evolution via descent with modification

Answer 10

Change in genetic composition of
populations over successive generations, eventually leading to the formation of new species

Question 11

define fit

Answer 11

Relationship between a character and a tree. The fit is obtained by
optimisation and is measured by the consistency index

Question 12

define drift with ref to small and large populations

Answer 12

Changes in the frequency of genes in a population due to the fact that (in
the absence of selection, gene flow and mutation) one generation is a random sample of the previous generation.

The stochastic (random) nature of this process means that gene frequencies can fluctuate randomly. This process will be more pronounced in small populations, where stochasticity is higher.

Question 13

Define gene flow

Answer 13

The movement of genes from one population to another via migration or dispersal.

Question 14

define homology in its 2 different senses

Answer 14

1. operational homology. can mean features of two taxa that a systematist considers are comparable (i.e. in some sense the “same”).
2. Evolutionary homology refers to features that are similar due to inheritance from a common ancestor. can only be established after a tree is constructed. An homologous character should only originate once.

Question 15

define homoplasy

Answer 15

Similarities between taxa that are not directly due to inheritance
from a common ancestor.
In other words character states that seem the same (operationally homologous) are not evolutionary homologues. Homoplasy includes reversal (taxa evolves a character state indistinguishable from one of its ancestors), convergence and parallelism

Question 16

define length

Answer 16

The length of a tree is equal to the total number of character state
changes on that tree. The shortest tree is the most parsimonious.

Question 17

define macro-evolution

Answer 17

Long-term process of descent with modification along phylogenies, reflecting the formation of species.

Question 18

define micro-evolution

Answer 18

Short-term process of descent with modification reflecting change in gene frequencies through time within populations.

Question 19

define monophyletic

Answer 19

A group of organisms is monophyletic if they have a common ancestor that is unique to them, i.e. all descendants of that ancestor must be included in the group.
Birds are monophyletic but reptiles are not.

Question 20

define mutation

Answer 20

The introduction of variant alleles to a population via a change in the genetic material of the reproductive cells.

Question 21

define Natural selection

Answer 21

The process in which organisms that are better adapted to their environment tend to survive and produce more offspring.

Question 22

define optimisation

Answer 22

Process of fitting characters to a tree in the simplest, most parsimonious or most likely way. Under parsimony, characters have to be optimised before consistency indices can be calculated.

Question 23

define parallelism

Answer 23

A type of homoplasy where two or more taxa independently evolve the same character state from the same ancestral state.

Question 24

define parsimony

Answer 24

Principle of explaining observed data in the simplest, most economical way possible.
In phylogenetics, parsimony is sometimes used to choose (from the (2n-5)!! possible trees for n taxa) one or more trees to summarise the data.

Recently it has been superseded by likelihood and Bayesian methods.

Question 25

define phylogeny

Answer 25

the actual pattern of descent, i.e. the historical relationship between organisms

Question 26

define phylogenetic inertia

Answer 26

the tendency for descendants to be similar to their ancestor (and hence for similarity between closely related species).

Question 27

define proximate explanations and give examples in terms of ontogeny, and mechanism

Answer 27

An explanation for a trait based on its immediate physical causation (“Mechanism” – e.g., the lens of the eye focuses light on the retina) and/or its development (Ontogeny – e.g. neurons need the stimulation of light to wire the eye to the brain).

Question 28

define sexual selection

Answer 28

A form of natural selection in which some individuals reproduce more than others because they are better at attracting mates.

Question 29

define ultimate explanations and give examples in terms of adaptation and phylogeny

Answer 29

An explanation for a trait in terms of the evolutionary forces that gave rise to it - Adaptation (e.g. the eye functions to find food and avoid danger) and Phylogeny (e.g. the vertebrate eye initially evolved with a blind spot and phylogenetic constraints prevent the evolution of a better solution).

Question 30

define operational homology

Answer 30

features of two taxa that a
systematist considers are comparable (i.e. in some sense the “same”).

Question 31

define evolutionary homology

Answer 31

features that are
similar due to inheritance from a common ancestor. Evolutionary homology can only be established after a tree is constructed. An homologous character should only originate once.

Question 32

key tenets of Evolutionary Psychology

Answer 32

1. massive modularity - mind consists of many evolved discrete modules
2. adaptationism - modules are adaptations for fitness
3. EEA adaptations designed to survive in Pleistocene hunter/gatherer enviro
4. psychic unity - human nature = universal panhuman design
5. evoked culture - differences across cultures produced by universal psychology responding to different circumstances