L05 - Human Evolution and Genetics

Question 1

Nature vs. Nurture

Answer 1

Nature – Genes determine behaviour

Nurture – Environment determines behaviour

Question 2

Nativism vs. Empiricism

Answer 2

Nativism – Nature – knowledge of the world is mostly innate and determine certain abilities (we are born with it)

Empiricism – Nurture – The mind is a clean slate at birth (tabula rasa) nothing like behaviour nor knowledge is inherited, it is all learned through one’s experiences

Question 3

What are species, genus and family?

Answer 3

Species: animals that tend to mate and produce fertile offspring.
We are of genus Homo (man) and species sapiens (wise).
Our family (all genera originating from same ancestor) is great ape

Question 4

What is Interactionism?

Answer 4

A mix of both Nativism and Empiricism – some genetic factors affect behaviour, but the environment can also affect it.

Some genes can influence the behaviour, but it is unlikely that genes code for things like gay relationships, religiosity, anxiety or mental disorders like schizophrenia.

More likely the environment affects these things.

Piaget’s theory of human development

Born with some innate knowledge/behaviours

Babies use this knowledge to start exploring the world

New knowledge-experience is assimilated into existing knowledge of the world

If experience does not fit with your existing knowledge, then the new experience needs to help accommodate by changing knowledge concepts

Disequilibrium – when innate knowledge and experiences do not match.

Question 5

Proximate vs. Ultimate causation

Answer 5

Proximate causation – Behaviour can be affected by close factors/experiences.
Internal changes of an animal like hormones, learning, experiences etc.
Explains “how” an animal produces a behaviour

Ultimate causation – evolutionary causes of behaviour
Explains “why” an animal behaves as it does.
Genes do not “cause” behaviour. They influence the development of the body which gives rise for certain behaviours to emerge.

Question 6

Out-of-Africa versus the multiregional hypothesis

Answer 6

Two competing hypothesis on the origin of modern humans

The Out-of-Africa hypothesis
Homo erectus originated in Africa and expanded to Eurasia about one million years ago
Proposes that a second migration out of Africa happened about 100,000 years ago, in which anatomically modern humans of African origin conquered the world by completely replacing archaic human populations (Homo sapiens)

Multiregional hypothesis.
Homo erectus originated in Africa and expanded to Eurasia about one million years ago
The multiregional hypothesis states that independent multiple origins or shared multiregional evolution with continuous gene flow between continental populations occurred in the million years since Homo erectus came out of Africa
(the trellis theory). A compromised version of the Out-of-Africa hypothesis emphasizes the African origin of most human populations but allows for the possibility of minor local contributions.

Question 7

What is Cognitive Revolution?

Answer 7

The cognitive revolution arose in the basis of a drastic increase in brain size. Our brain is about 2.5% of body weight, but consumes 25% of body resting energy (compared to 8% of brain of apes)

Question 8

What are Consequences of increase in brain development affecting our mind/behaviour?

Answer 8

we spend more time looking for food to provide energy for brain

muscle atrophy to help feed energy needs of brain

human premature birth due to bigger brain of newborn and smaller pelvis of mother (upright walk)

babies are very plastic and not “set” in their way: highly adaptive

human children are helpless for a long time

requires raising child by help of group; evidence for “kindergartens” as early as homo neanderthalensis

cooking (handling fire), which increases nutritional density of food and dramatically improves digestion speed

a very special language

possible friendliness

Question 9

What are Advantages of cognitive revolution?

Answer 9

Humans have a language that is unparalleled compared to the languages of other animals. It endowed us with significant characteristics, different to other apes (and probably other members of our family)

Ability to communicate knowledge about world.

Planning complex actions (e.g., avoiding predators)

Ability to communicate about social structure.

Larger groups of humans can live together (up to 150, after that information cannot be share effectively about everyone).

Ability to communicate about things that do not exist (such as myths, laws, rules, concepts, etc.

Friendliness, Cooperation of strangers (myths, concepts);

rapid innovation of social behaviour (laws, traditions);

Increasing size of functional human societies from kinship tribes to
villages, cities, nations

Question 10

What is the Agriculture revolution?

Answer 10

For 100K years hominids depended on hunting and gathering for survival.

Humans followed their food around, camped around protective sites and waterholes.

But 8K years ago agriculture emerged, animals were domesticated

Question 11

Consequences of agricultural lifestyle .

Answer 11

Concept of ownership

Instead of kinship tribal bands, villages and cities and nations became default social structures.

Diet change from wholesome and varied to monocultural. Nutrition- related diseases occurred.

Settled humans have reduced knowledge about the wider surroundings, such as animals, plants, geography, etc. compared to nomadic humans.

Sedentary lifestyle due to spending significant more time on working for food compared to hunter and gatherers. Work-related diseases emerged.

Evolutionary Psychologists argue that our minds remained hunter-gatherer minds and our behaviour reflects this. We are not yet adapted to the setlled lifesyle

Question 12

What is Baby schema (Kindchenschema)?

Answer 12

Certain facial characteristics have a high appeal to humans, inducing perception of “cuteness”, eliciting caretaking behaviour.

The perception of cuteness emerges early in human development (3-6 yrs).

Features inducing baby schema: large head and a round face, a high and protruding forehead, large eyes, and a small nose and mouth.

Commonly found both in human and animal infants

Question 13

What is Piloerection (“goosebumps”)?

Answer 13

Hairs “stand up” as a reaction to fright, cold.

Inherited from our ancestors who had fur.

Makes us look bigger and scarier. Also helps keep air around skin, insulating us from cold.

Question 14

What are Human innate behaviors?

Answer 14

Unconscious use of environmental features provide cover
Social behaviour
Grasping reflex
Smiling and laughing

Question 15

What is proof of the innate human behaviour for smiling and laughing?

Answer 15

Boy blind and deaf from birth can smile and laugh. Impossible to learn this by imitation

Question 16

What is proof of the innate human behaviour for grasping reflex?

Answer 16

Human newborns are remarkably strong, being able to support their own weight with the grasping reflex.

This innate behaviour seems to reflect the fact that primates used to have fur, and grasping allowed the newborn to attach itself to the mother

Question 17

What is proof of the innate human behaviour for social behaviour?

Answer 17

Stretching out hand in primates and humans signals initiation of contact
Body contact signals affection, caring

Some ethologists have argued that human behaviour to pet/caress/ gentle touch comes from primate behaviour of social grooming (allogrooming)
Because of the way our species evolved, many abilities, tendencies, and characteristics are:
either present at birth in all human beings, or
develop rapidly as a child matures
Examples of such inborn characteristics:
inborn reflexes
an attraction to novelty
a motive to explore and manipulate objects
an impulse to play
the capacity for certain basic cognitive skills

Question 18

What is the unconscious use of environmental features provide cover

Answer 18

Children love to build caves, little forts, hideaways

Most humans prefer to sit with back against wall

In an empty room, humans first occupy seats at corners and at the borders/edges

If available, we prefer higher lookouts for dwellings

Question 19

What is DARWIN’s THEORY OF EVOLUTION - Natural selection?

Answer 19

Those organisms best adapted to their environment have a better chance of surviving and reproducing.

This theory of evolution involves the following factors
Rapid multiplication
Limited environmental resources
Struggle for existence
Variation/Mutation
Survival of the fittest
Inheritance of the useful variation Formation of new species

Question 20

What is Rapid multiplication?

Answer 20

Many organisms reproduce more offspring than can survive (e.g., plants produce thousands of seeds; cod fish lay >million eggs).There are random mutations in the genes of offspring compared to parents.

Question 21

Describe the issue Limited environmental resources?

Answer 21

Increase of population requires mores resources (space and food), but both are limited and often relatively constant. Individuals compete for these limited resources.

Question 22

What is Struggle for existence?

Answer 22

(struggle for existence; BUT SEE SYMBIOSIS!). The competition for the limited resources as well as for mates plays out on three levels: intraspecific (within species), interspecific (between species), environment (eg. flood, drought etc).

Question 23

What is Variation/Mutation?

Answer 23

Because environment changes, the more genetic variation (mutation) within a species, the more likely it can adapt. Some traits in individuals allow them to adapt better to the environment than other organisms can.

Question 24

What is Survival of the fittest?

Answer 24

(natural selection). Individuals with most adaptive traits have higher probability to reproduce and pass on their genes. Natural selection acts on phenotype

Question 25

What are Genes?

Answer 25

Cells contain nuclei, which contain chromosomes, which contain DNA.

Hereditary transmission of traits requires chromosomes, i.e., DNA.

Question 26

What are Genes?

Answer 26

Cells contain nuclei, which contain chromosomes, which contain DNA.

Hereditary transmission of traits requires chromosomes, i.e., DNA.

Question 27

What are Chromosomes?

Answer 27

Cells contain chromosomes, which contain DNA, which contains genes that code for traits and non-coding areas that likely code for gene expression

Question 28

What are Diploid set ?

Answer 28

Cells in human body generally contain 46 chromosomes (=23 pairs; diploid set)

Question 29

What are Haploid set ?

Answer 29

Female egg and male sperm contain only 23 chromosomes (one half of each pair, haploid set)

Question 30

What are DNA?

Answer 30

DNA (deoxyribonucleic acid) is a complex molecule which contains the genes.

DNA contains information allowing cells to function

Question 31

What are Allele?

Answer 31

We inherit the genes coding for the same features once from our mother and once from our father. These different forms are called alleles

Question 32

What is Homozygous?

Answer 32

Homozygous: the alleles code for the same phenotype

Question 33

What is Heterozygous?

Answer 33

Heterozygous: the alleles code for different phenotypes. The expressed phenotype reflects the coding in the dominant gene. The recessive gene is usually not expressed

Question 34

What is Genotype?

Answer 34

The complete set of an organism’s genes.

Question 35

What is Phenotype?

Answer 35

The overt characteristics of an organism, i.e., the properties we can observe (resulting from what genes are expressed) Phenotype is product of genotype and environmental factors, and experience.

Example: skin color of humans. Our genes determine how much melanin we produce, but exposure to UV-B radiation can increase melanin production, which darkens the skin because melanin is black

Question 36

What are Fraternal twins ?

Answer 36

Separate eggs fertilized by two separate sperms

Share half their genes

Question 37

What are Identical twins ?

Answer 37

Single egg fertilized by single sperm, then split in two

Share all of their genes

Question 38

What did the Study design: groups required to examine to what extent performance on IQ tests reflects the influence of inherited traits or environmental factors during childhood development prove?

Answer 38

Biological parents and child – shared genes

Adoptive parents and child – shared environment

Monozygotic twins growing up together
Provides data for equal “nature”, similar “nurture”

Monozygotic twins growing up apart
Provides data for equal “nature”, different “nurture”

Dizygotic twins growing up together
Provides data for similar “nature”, similar “nurture”

Dizygotic twins living apart
Provides data for similar “nature”, different “nurture”

Siblings growing up together
Provides data for similar “nature”, similar “nurture” (but did not share womb at same time)

Individuals not related to each other living apart
Baseline control group.

Provides data for genetically unrelated, separately living individuals that should correlate in IQ scores randomly

Monozygotic twins tend to resemble each other in intelligence, whether the twins were raised together or not. Dizygotic twins show less resemblance, even if they were raised together, although they resemble each other more so than randomly selected individuals

Question 39

What is a Prokaryotic cell?

Answer 39

According to the fossil record, the first cellular life forms were unicellular prokaryotic cells.

These cells had no membrane-bound organelles, such as mitochondria, and had no nucleus (their name denotes that: “pro”=before, “karyon”=kernel).

They have thus none of the basic features of plant or animal cells.

For millions of years, these were the only cellular life forms on Earth, according to the fossil record

Question 40

What is Eukaryotic cell?

Answer 40

Eukaryotic cells found in plants and animals contain specialised organelles, some of them surrounded by a membrane.

Mitochondria, for example, are organelles that also have their own DNA. The cell cannot make mitochondria, they reproduce independently by binary fission (like bacteria)

Eukaryotic cells found in plants and animals contain specialised organelles, some of them surrounded by a membrane.

Mitochondria, for example, are organelles that also have their own DNA. The cell cannot make mitochondria, they reproduce independently by binary fission (like bacteria).

The evolution of eukaryotic cells may not have been the result of mutation and natural selection alone, but also symbiotic processes

Question 41

What is the Symbiogenetic theory

Answer 41

According to the symbiogenetic theory, different life forms not only arose from mutation and natural selection, but also from cooperative merging of two independent life forms entering a state of symbiosis

Theory of symbiogenesis introduces evolutionary processes to explain the origin of species in addition to random mutation and natural selection. The theory proposes that eukaryotic cells arose from symbiosis of singly living prokaryotic life forms.