LO5 - Human Evolution and Genetics

Question 1

Nature

Answer 1

This links to the idea of nativism - everything we know about the world is innate and genetic. It is this that determines behaviour.

Question 2

Nurture

Answer 2

This links to empiricism - we are born with a tabula rasa and nothing in terms of behaviour and knowledge is inherited. Everything is learned.

Our past experiences determine individual differences.

Question 3

Interactionism

Answer 3

We are born with some behaviours but our experiences can influence our behaviour and how it is expressed in the future. Experiences can also change which innate behaviours are expressed.

What is expressed in the future is based on the interaction between nature and nurture.

Question 4

Nativism

Answer 4

Most of the knowledge we have is innate (view held by Descartes) and we are born with it. It is this alone that determines out behaviour.

It is associated with the nature side of the debate and genetics. We can look at genetics and inherited characteristics to explain behaviour.

Question 5

Empiricism

Answer 5

We are born as a blank slate with no innate behavioural knowledge. Everything we know is learnt.

Watson and Locke held this view. It is associated with nurture. We need to look at a child’s individual history to understand their behaviour.

Question 6

Proximate causation

Answer 6

The close causes: these are the things related to the internal changes of an animal such as hormonal state, learning and experiences.

This explains how an animal produces a behaviour and takes a reductionist approach.

Question 7

Ultimate causation

Answer 7

This is related to evolutionary causes of behaviour (why an animal behaves the way it does).

Functionalism is interested in this question.

Question 8

Species

Answer 8

A group of animals that can mate, do mate and produce fertile offspring.

Question 9

Genus

Answer 9

A group of species that have evolved from a common ancestor

Question 10

Family

Answer 10

All of the genera that originate from the same ancestor.

Question 11

Homo Erectus

Answer 11

This was the first from our genus that left Africa. They were very conservative and used the same tools. They didn’t have the flexibility and development of culture that Homo Sapiens have.

While it could create tools, it could not adapt in the same way.

Question 12

Homo neandertahlensis

Answer 12

Another species within our genus. The migrated out of Africa in a different route to Homo Erectus.

Their DNA is found in modern humans (mostly Asians and Europeans).

They mated with Homo Sapiens at some point.

Question 13

Homo Sapiens

Answer 13

This is our species. We used to coexist with other Homo species.

What differentiates us is our large brain. We are a young species but had the most flexible culture which showed the most development.

We also moved out of Africa. Our increased brain size sparked the cognitive revolution.

Question 14

Out of Africa Hypothesis

Answer 14

We came from Africa. The first Homo genus were born there and from there we left and explored the planet.

Homo Erectus was the first to explore the planet and entered Europe and Asia.

Question 15

Multi-regional hypothesis

Answer 15

This is the idea of several migratory waves out of Africa. Includes the different routes that the different species within Homo genus took.

Another group of Homo evolves from the earlier group and continues to migrate.

It is not simply in Africa that humans evolved.

Question 16

Cognitive revolution

Answer 16

This is characterised by the explosion in brain size that distinguishes us from our ancestors.

Humans have cultural abilities, lifestyles and interactions that Homo Erectus was not capable of because of brain size.

The brain is an enormous energy sink and the size of it is the result of a random nutation in one gene.

Question 17

Consequences of the cognitive revolution

Answer 17

We have to spend more time looking for food to feed our brain.

Humans are born prematurely because of our skull size. Babies are very plastic and are helpless for a long time.

Raising children is a shared responsibility. We cook with fire which increases the nutritional density of food.

Language is far more complex. Helps us survive by communicating, planning etc.

Language also lets us talk about theories and allows for rapid innovation.

Question 18

Agricultural revolution

Answer 18

Around 8000 years ago, hunter-gatherers settled down and agriculture emerged and animals were domesticated.

We discovered food grew from seeds and animals could be tamed. Shift in culture occurred. We required permanent houses near our crops.

Question 19

Consequences of agricultural revolution

Answer 19

Ownership as a concept emerged. You protect the things you think are yours.

Larger societal structures emerged e.g. villages/cities. We are not adapted to this.

Diet changes - it got worse as we only eat the crop we grow. Cohabitation with animals resulted in disease.

Loss of knowledge - in one generation all nomadic knowledge was lost.

We had to work harder - plants and animals require more labour.

Question 20

Advantages of the agricultural revolution

Answer 20

We could have more children at once. This was also needed to look after the crops.

No need to carry children around. It didn’t matter so much when one child dies.

Population grew a lot.

Question 21

Scientific Revolution

Answer 21

We developed methods that allowed us to explore the nature of things. We are able to control nature to an extent and the introduction of science ensured our survival despite not being at the top of the food chain.

Question 22

The Anthropocene

Answer 22

We are in a position now to modify the entire biosphere due to our knowledge and lifestyle. This may be the last phase if we are not cautious.

We have manipulated the planet so much that it may not be able to habitate us anymore.

Question 23

Gene

Answer 23

Within each cell’s nucleus we have strands of genetic material (chromosomes) which contain DNA which is used to express certain traits.

DNA produces nRNA which codes the building block proteins of an organism. DNA contains all the genes that low a cell to function.

Question 24

Chromosomes

Answer 24

46 chromosomes contain all of our genetic material. Each cell contains many mitochondria that contain their own DNA meaning there is more than one set of genetic material in each cell.

Our chromosomes look similar to chimps but other organisms have far more pairs - the number does not relate to advanced development.

Question 25

Diploid set

Answer 25

We have 23 pairs of chromosomes which makes up a diploid set.

Normal human cells contain 23 pairs of chromosomes

Question 26

Haploid set

Answer 26

The sex cells of a human have a haploid set of chromosomes (only 23). They don’t have pairs.

Two combined haploid sets produce a diploid set in the offspring which allows us to inherit traits from both parental lines.

Question 27

Genotype

Answer 27

The complete set of an organisms genes

Question 28

Phenotype

Answer 28

The overt characteristic of an organism (properties we can observe resulting from what genes are expressed).

Phenotype is a product of genotype and environmental factors and experience.

Question 29

Nucleus

Answer 29

Within a cells nucleus is the genetic material.

Prokaryotic cells have no nucleus, only Eukaryotic cells (plant and animal cells) have a nucleus.

Question 30

Allele

Answer 30

These are different forms of the same gene.

We inherit a combination of features from our parents (two sets of genetic coding). These different forms can be called alleles and can either be hetero or homo zygous.

Question 31

Heterozygous

Answer 31

The alleles code for different phenotypes. The expressed phenotype reflects the coding in the dominant gene.

Question 32

Homozygous

Answer 32

The alleles code for the same phenotype.

Question 33

Innate human characteristics

Answer 33

What are we born with? These are phylogenetically preserved behaviours across the species. E.g. Baby Schema.

Question 34

Baby Schema

Answer 34

It is the reaction to a specific set of facial characteristics that adults express.

Human babies have: large heads, round faces, large eyes and a small mouth and nose.

This causes adults to carry out caretaking behaviours as these characteristics have a high appeal to humans as this induce a perception of cuteness.

Caretaking behaviours ensure the survival of infants.

Question 35

Piloerection

Answer 35

This is hairs standing on end as a reaction to cold or a fight.

We see this behaviour in animals raising their hackles. This makes them look bigger.

When we are cold this occurs to create a layer of warm air between the skin and outside - it insulates.

Question 36

Inborn preferences

Answer 36

There is a preference to seek cover (building forts and caves). As humans are not at the top of the food chain we like to hide.

Adult humans also prefer to fit in corners.

We also prefer higher looking for our dwellings as this is safer.

Question 37

Inborn abilities (social)

Answer 37

Primates stretch out hands to initiate contact.

Body contact signals affection/caring. This is the same in all primates and is used to establish trust.

Behaviour of petting/caressing is primate behaviour of social grooming. Purpose of keeping clean.

Question 38

Inborn abilities (facial expressions)

Answer 38

We share facial expressions with primates (grimacing). We have similar facial expressions with strong emotions as those of chimps.

Similar facial expressions allow us to conclude that others have the same inner state as us. We can only speculate - this is theory of mind.

Question 39

Innate behaviours

Answer 39

These are not learnt but given to us through genetics. These are part of our species behavioural knowledge.

We have adapted to a hunter-gatherer lifestyle as this is what the majority of our ancestors did. Babies come with behaviours that promote their survival to this kind of lifestyle.

Question 40

Inborn reflexes

Answer 40

These aid survival.

We also have an attraction to novelty which helps us to develop our knowledge of the world.

We have motivation to explore and manipulate objects.

Play behaviour simulates adult life.

We have basic cognitive skills e.g. numerical.

Question 41

Moro reflex

Answer 41

The arms spread out then pull in then the infant starts to cry. This is present at birth and is a startle reflex associated with a loss of balance or support.

It is a survival reflex as the baby wants to cling to their mother. If they lose balance and try to grab their mother but they are not there, the baby will try to get its attention.

Question 42

Grasping reflex

Answer 42

Infants can support their own weight with grasping. Mothers has fur and previously this would have been to attach the baby to its mother.

Question 43

Feeding/Rooting reflex

Answer 43

If the corner of a baby’s mouth is touched, it turns towards the stroking and roots.

If the baby had to learn to feed this would be a risk for survival. It helps for breastfeeding.

Question 44

Crying

Answer 44

Extremely efficient innate behaviour. It is well coordinated and high in energy consumption.

it is primal communication and ensures a caring reflex from parents as it is both worrying and irritating.

It activates the centre that promotes fear and adults try to rectify this as we want the sound to stop.

Question 45

Laughing

Answer 45

It is innate as blind and deaf children still show it.

It is universally human and part of our social behaviour - it serves a purpose.

Question 46

Trait

Answer 46

These are commonalities such as personality, emotion, sexual behaviour and reasoning that can be traces to evolution and natural selection.

Question 47

Twin studies on heritability (interactionist findings)

Answer 47

Groups are created to examine the extent to which performance on IQ tests reflects the influence of inherited traits or environmental factors during development.

Monozygotic twins growing up together/apart
Dizygotic twins growing up together/apart
Normal siblings growing up together
Individuals not related to each other living apart (control)

Similarity in intelligence was highest in monozygotic twin who grew up together, then those who grew up apart, then dizygotic twins living together then siblings reared together.

Inheritability estimates for intelligence are around 40-50% in children and young people and 60-80% in adults.

Scores of adopted children correlate more with the scores of their biological compared to non-biological relatives.

Question 48

Dizygotic twins

Answer 48

These come from two eggs being fertilised by two sperm.

They are two organisms with a different genetic makeup.

Question 49

Monozygotic twins

Answer 49

They come from one sperm fertilising one egg the then the egg splitting to form two zygotes.

They are genetically identical.

Question 50

Heritability

Answer 50

A statistical estimate of the proportion of variability in the population for some trait is attributable to genetic differences between the group

Question 51

Natural Selection

Answer 51

Darwin’s theory of evolution has this at its core. Those organisms who are best adapted to their environment survive and have a better chance of reproducing.

These traits are delivered to the next generation and the number of adapted organisms increases.

Question 52

Rapid multiplication

Answer 52

There are so many life forms that produce far more offspring than can actually survive.

There are random mutations in the genes of offspring compared to parents. Genetic material is not identical between parents and offspring. This generates variation.

Question 53

Limited resources

Answer 53

Organisms must compete to get resources. An increase in population requires more resources (space and food). However, both are limited and often relatively constant. Individuals compete for these resources.

Humans may decide to be agriculturalists as it gave us some control over these limiting factors.

Question 54

Struggle for existence

Answer 54

Occurs over limited resources but also available reproductive partners. It is both intraspecific and inter specific. All animals in a habitat compete for the resources.

It also plays out on the environmental level as individuals compete for space to live.

Symbiosis provides another view of this. Cooperation is seen.

Question 55

Variation and mutation occurs (genetic material changes)

Answer 55

As the environment changes, the more genetic variation within a species, the more likely it is to adapt as it is more likely that a mutation will have occurred that increases the ability of the species to survive.

If environment changes but not changes occur in the organism, the species will go extinct as it cannot adapt.

Some traits in an individual allow them to adapt better to environment.

Question 56

Survival of the fittest

Answer 56

Individuals with more adaptive traits will have higher probability of reproducing and passing on their genes. Natural selection acts on phenotype. Advantageous genes are passed on to the next generation.

Inheritance of useful variation allows for the formation of new species.

Question 57

Endosymbiosis theory

Answer 57

This contests that the world is a fight for survival.

Previously, life has developed by one organism absorbing another and taking in the qualities of both organisms to form a new species.

Endosymbiosis is the process of cells living together. One organism lives inside another and cells stated to become highly complex as they were filled with chloroplasts and mitochondria.

Question 58

Prokaryotes

Answer 58

These were the first living organisms - they were unicellular and had no membrane-bound organelles such as mitochondria/nucleus.

They have none of the basic features of plant and animal cells.

They had the ability to absorb other organisms by wrapping their cell membranes around them.

Question 59

Eukaryotic cells

Answer 59

These are the plant and animal cells that we see today. They contain specialised organelles, some of which are membrane-bound.

For example mitochondria are an organelle with their own DNA. They reproduce themselves through binary fission.

Question 60

Evidence for Symbiotic theory

Answer 60

Cells aren’t able to contain some of the structures within them e.g. mitochondria - they must have absorbed them.

Chloroplasts and mitochondria have their own DNA which is strikingly similar to that of bacteria. Ribosomes also have the same structure to that of ancient bacteria.

Two layers of membrane for these organelles suggest that the outer membrane used to belong to the cell that engulfed them.

Question 61

Binary Fission

Answer 61

This is different to sexual reproduction as it only requires one bacterium to divide and reproduce.

DNA replicates itself then the cell splits in two, both of which containing identical DNA.

Question 62

Consequences of endosymbiosis

Answer 62

Endosymbiosis can account for the origins of the vast variety of eukaryotic organisms.

Absorbing process allowed organisms to combine powerful abilities and become better adapted for life on earth. This resulted in the plants and animals we see on earth today.

Life as we see it now is the result more of cooperation than competition.