Genetics and Behaviour

Question 1

Darwin (1859) natural selection

Answer 1

Evolution occurs throughput species as traits of successful individuals are passed down generations

Dark moth and light moths - smog industrial revolutions - light moth - birch tree

Owl butterfly - eyes on the wings, bird avoided food next to eye spots (Blest, 1975)

Question 2

Neoteny in evolution of human skull

Answer 2

the human skull was similar to the chimpansee but we have a bigger frontal cortex.

Question 3

evolution of human brain

Answer 3

brain size has increased during evolution. Most of the increase in size has occurred in the cerebrum

Increased convolutions in the cerebrum have served to increase the volume of the cerebral cortex.

Question 4

brain to body weight ratio

Answer 4

humans have the highest brain to body weight ratio in mammals except the tree shrew

Question 5

percentage of body weight is brain matter

Answer 5

brain makes up 2.3% of total body weight, elephant makes up 0.2%.

Prenatal brain weighs 350g containing 100 billion neurons

New neurons ceases expect in hippocampus and olfactory bulb, already present ones create new connections

Late adolescence - human brain reaches adult size of 1400g - 4 x the weight of a newborn’s brain

Question 6

Similarity with mammals

Answer 6

only 1.2% difference between human and chimpanzee brain

1.4% difference between gorilla and human

2.4% difference between orangutan and human

Question 7

History of evolution

Answer 7

human and chimpanzee lineages diverged from a common ancestor about five to six million years ago

Australopithecus (southern ape) species played a role in human evolution, genus homo being derived from Australopithecus after 3 million years ago.

First hominid to leave Africa around 1.7 million years ago (homo erectus)

Humans (homo sapiens) evolved in East Africa around 100,000 years ago

Question 8

Mendel’s theory

Answer 8

brown and white peas (put into context of eye colour)

First generation:
Homozygous bb (recessive allele blue, recessive allele blue)

Homozygous BB (dominant allele brown, dominant allele brown)

Creates Bb, Bb, Bb, Bb

Second generation:
Heterozygous Bb

Creates Bb, BB, bb, Bb
So one out of the 4 = blue eyes even if both parents have brown eyes

Question 9

Genotype

Answer 9

genetic make up of alleles

Question 10

Phenotype

Answer 10

observable trait from combination of alleles

Question 11

DNA

Answer 11

DNA in the nucleus of cells, contain alleles.

Banister of staircase are made up of sugars and phosphates

Rung of staircase are nucleotide bases adenine, thymine, guanine and cytosine.

Bases always reattach to the same type of base A to T and G to C.

Apple Tree, Car Garage =
Letters of gene codes

Question 12

Watson and Crick (1962)

Answer 12

humans have 23 pairs of chromosomes

Sets of genes control a trait sit at the same site of the chromosome called an allele

Genes direct the synthesis of protein

Question 13

Protein synthesis

Answer 13

1. DNA unravels exposing structural gene that is to be expressed
2. Transcription: a strand of messenger RNA is transcribed from one of the exposed DNA strands and carries the genetic code from the nucleus into the cytoplasm
3. In the cytoplasm the messenger RNA attaches to a ribosome. Ribosome moves along the strand attaching to an appropriate amino acid, added to the lengthening protein by a molecule of transfer RNA
4. When the ribosome reaches the end of the messenger RNA strand, a codon instructs it to release the completed protein.

Question 14

Meiosis

Answer 14

process of genetic transmission of gametes (sperm and egg cells)

Question 15

Human chromosomes

Answer 15

Humans have 23 pairs of chromosomes

Gender determined by 1 pair of chromosomes

All females have an exact pair of XX

All males have a mismatch pair of XY

Y is the smallest chromosome in humans

Chromosomes have 1,500 genes and Y has less than 200

Question 16

sex-linked traits

Answer 16

coat colour in cats
Male XY
Female XX

Ginger and Tabby (tortoiseshell) on 2 X chromosomes

So only females can be tabby and ginger

Colour blindness and haemophilia
Dominant H = do not have Haemophilia
Recessive h = do have haemophilia

Females can be heterozygous or homozygous (hh, Hh, HH)

Males only have one gene (H, h) so if males have recessive gene they have haemophilia = more common in men

Question 17

Single gene disorders

Answer 17

Down syndrome caused by a chromosomal aberration - resulting in an extra 21st chromosome.

Phenylketonuria (PKU)

Discovered by a Norwegian Dentist called Asbjorn Folling

PKU is transmitted by a recessive gene mutation on chromosome 12. Can’t break down phenylalanine, amino acids common in food as a result build up in blood = Bari damage

Hospitals screen for high levels of this amino- acid, reduction of phenylalanine in diet = relieves symptoms

Question 18

Maze bright Maze dull tyron - genetic control of cognitive ability

Answer 18

Rats running through a maze, then separated the fast rats and the slow rats so the slow rats bred with other slow rats and vice versa

By the fourth and especially 8th generation there as a high difference between the two groups

There was only a difference however in the improvised environment and hardly any difference is in an enriched environment.

Question 19

twin studies

Answer 19

Fraternal twins- from two eggs individually fertilised (dizygotic)

Identical twins - from one egg that spilt after fertilisation (monozygotic)

Bouchard, 1998 - Minnesota study twins reared apart showed that identical twins more similar than fraternal twins on all psychological dimensions

Turkheimer et al. 2003 - heritability of IQ was near 0 in improvised twins and near 1 (maximum) in affluent twins - epigenetic - environment and genetics do play a role

Question 20

Darwin - advantageous behavioural traits

Answer 20

older males attracted to younger females = healthier offspring

Social dominance is adaptive because dominant males produce more offspring than non-dominant males

Evolutionary pressure to take on imposter offspring overrides costs of mistakenly rejecting your own (Fisher, 2003)

It is good to have a healthy chick (saino et al, 2000)

Group-benefit group selection - hereditary characteristics benefit a group but harm an individuals chance of reproducing, they will be eliminated over time (no matter how good they are for the group)

Question 21

sentinel behaviours

Answer 21

Clutton-Brock (1999)
Include direct fitness

Question 22

direct fitness

Answer 22

traits that will increase the ability to survive and contribute large numbers of fertile offspring to the next generation

Sentinel behaviour provides an advantage to the individual as it is the first to see the predator and the first to escape

It does not have a disadvantage in terms of stopping it feeding as the individual will only engage in the behaviour after it has finished feeding

Question 23

indirect fitness

Answer 23

trait increases ability to help kin survive and contribute large numbers to fertile offspring to the next generation.

The animal making an alarm sound is most likely to get eaten so it doesn’t benefit the individual but benefits the colony

Only females make alarm calls - males are not related to the rest of the colony so do not gain enough indirect fitness by saving others

Question 24

Hamilton rule of altruistic behaviour would evolve

Answer 24

R x b - c > 0

R = relatedness to recipient
B = benefit to the gene pool of act,
C = cost of act

Question 25

kin selection in people and animals

Answer 25

Beldings ground squirrels are less aggressive and more altruistic to half siblings reared apart than to unrelated individuals reared apart Mothers can recognise photographs of their infants within 33 hours of birth, strangers can match photographs of mothers to their infants, suggesting a physical resemblance among kin (Porter et al. 1984) Porter and Moore (1981) - smelly children and siblings Gustafsson et al. 2013 - both mothers and fathers reliably recognise their infants cries Communal bank swallows breecher (Beecher and Hahn, 1981) Solitary Tree Swallows (Leonard ert al, 1997)

Question 26

extreme altruism

Answer 26

extreme altruism is bringing up sisters instead of daughters Eusocial societies in hymenoptra Societies which exhibit: cooperative care of brood, reproductive division of labours, overlapping adult generations

Question 27

bees haplodiplody

Answer 27

mother-offspring genetic relatedness = bees each daughter shared 50% of her chromosomes with her mother Sister-sister genetic relatedness = in bees the genetic similarities is on average 75% of genes shared between sisters As a result a female passes more genes on by helping raise sisters than flying off and raising daughters

Question 28

eusocial vertebrates

Answer 28

Naked mole-rats Like bees - have a division of labours, queen largest and long lived, other females do not breed. Unlike bees - diploid and no difference in physiology Factors leading to eusocial society: inbreeding, living in a contained nest, harsh conditions outside of nest

Question 29

Altruistic behaviour in non-eusocial vertebrates

Answer 29

helpers at the Nest Emlen (1997), predicting family dynamics, in behavioural ecology Florida scrub jays help siblings as it will increase indirect fitness

Question 30

Regions of the cortex that processes in incoming stimuli

Answer 30

Association cortex