The contributions of heredity to our physical structure and behaviours

Francis Galton (1869) viewed Nature and Nurture as competing for control over structure and behaviour, but today psychologists believe that the two are closely intertwined in particular types of behaviour.

The contributions of environmental factors and experience to our physical structure and behaviours

Subtopic

This occurs when genetic instructions are used to produce a particular protein

The process in which genetic instructions are converted into a feature of a living cell

Although each cell contains the instructions for the entire human organism, only a subset of instructions is expressed at any given time and location

Gene expression in a nerve cell is different from that in a muscle or skin cell.

Subtopic

One of several versions of a gene

Having 2 of the same alleles for a gene

If both parents contribute the same type of allele, the child would be considered homozygous for that gene.

Having two different alleles for a gene

If parents contribute two different alleles, the child is geterozygous for that gene

These determine a phenotype only when an individual is homozygous for a particular gene

Written as lower case letters

These determine a phenotype in either homozygous or heterozygous condition.

Written as a capital letter

A small segment of DNA located in a particular place on a chromosome

Each gene contains instructions for making a particular type of protein

Observable and physical characteristics

A personal set of instructions

Half come from Mother and Half come from Dad

A structure found inside the nucleus of a single cell

Made up of proteins and DNA organized into genes

Each cell normally contains 23 pairs of chromosomes

A set of intructions for building a human

Basic building blocks of all living things.

In most cells there is a structure called the Nucleus which contains the genome.

In humans the genome is split between 23 pairs of chromosomes

The prbability that two people share copies of the same allele from a common ancestor.

Relatedness is usually computed within a limited number of generations

The chances that you share an allele with one of your parents is 1/2. Same as for a sibling. First cousins have a 1/8 likelihood of sharing an allele.

Of the 23 pairs of human chromosomes from each parent, 22 are perfectly matched. ie. A gene appearing on one of a pair of chromosomes has a corresponding gene on its partner.

X chromosome is larger and contains roughly 2000 active genes.

Y chromosomes have fewer than 100 active genes.

Females carry XX Chromosomes

Males carry XY Chromosomes

Descent with modification from a common ancestor

Charles Darwin proposed that species evolve or change from one form to the next in an orderly manner.

A farmer's goal to raise the strongest oxen might be accomplished by the breeding the strongest available oxen with each other. This is known as artificial selection

Natural selection is the process by which survival and reproduction pressures act to change the frequency of alleles in subsequent generations

Evolution can result from mutation, migration and genetic drift

A mutation is an error that occurs when DNA is replicated. Mutant alleles providing some advantage spread through the population. While those that result in a disadvantage disappear from future generations.

Migration occurs when organisms move from one geographical location to the next.

Genetic drift produces change from one generation to the next through chance or accident

Any consideration of evolution must include the question of what natural selection selects. Natural selection favours the organism with the higest degree of fitness.

Fitness is defined as the ability of one genotype to reproduce relative to other genotypes. The concept of fitness includes survival to adulthood, ability to find a mate and reproduction.

Refers to the process or result of change because of natural selection. ie. a species can respond to an environmental change by adapting, and features of the new phenotype are called adaptations

Adaptations can be behaviours (jumping higher) or anatomical features (eyes that see colour)

Any adaptation that is good enough to contribute to the fitness of the organism will carry forward into future generations.

Over 7 million years homonims (species that walked on 2 feet and had large brains) brains grew quickly, suggested improved intelligence was translated into substantial advantages in survival.

The major factor distinguishing human intelligence from that of other species is the richness and complexity of social behavior.

Distinguishing between friend or foe, imitate the behaviour of others, use language, recognize and anticipate emotions, thoughts and behaviour of others, maintain relationships and cooperate required the evolution of a special brain.

Evolutionary psychology is a direct descendant of the functionalism support by William James

Current behaviour exists because it provided some advantage in survival and reproduction to our ancestors

Behaviour is seen as promoting survival as opposed to being random and pointless. It serves as a function for a species survival.

The goal of evolutionary psychology is to explain how the patterns of behaviour that we share with other humans have been shaped by evolution.

Belonging to a social group provides the benefits of mutual protection and assistance. Being on the perimeter is risky for fish swimming in a ball as predators will hunt on the perimeter as it is easier to isolate prey. The same is true for humans and explains why we reacts emotionally when we believe we are being socially excluded.

Being social carries costs and benefits. Social animals face injury in competition for food and mates and are exposed to contagious illness.

Individuals either benefit or do not benefit from the interaction, ultimately affecting their survival and reproductive success.

Darwin's term for the development of traits that help an individual compete for mates.

Parental Investment

Traits influenced by sexual selection

Human societies are directly influenced by our biological history but also culture. Cultures provide practices, values and goals shared by a group of people. Experiences shapes by culture interact with survival and reproductive pressures.

With all the flaws of our groups: families, communities or nations, humans retain a strong need to belong. Humans do not thrive in isolation. Humans dependence on kinship, friendship and group membership continues to influence our behaviour.