4.5 billion years ago  earth. First signs of animal life was a billion years after that.

First forms were simple, and bacterial.
First 3 billion years, nothing more complex than algae evolved.Explosion: 10 million years. The Canary Explosion (Sp?).
Sea and bird evolved.
Darwin’s theory explains how/why these species came to be.
Nothing to do with origins of life, but with evolution.

Amino Acids: proteins in cells (found in lightning).

Darwin: interest in natural history, collected minerals, bird’s eggs, insects etc. Did not do well in school, went to medical school, graduated at 22.

Invited to be a specimen collector in The Beagle. 2 year trip.
Was a decon.

No theory about evolution. Did species evolve from other species, or did they come in a different time in creation? Either God created animals to change their form, or that God created life.

Darwin wanted to explain how animals evolved into other forms. – Galapacos Islands.
Published his Evolution 25 years after his voyage. Killed himself?

Darwin saw a variety of animal types he had never seen before. Lived in separate, distinct groups.

Must have branched out in some way from other types of animals.
Studied his notes, and came up with the theory of natural selection.

Read an essay by Malthus  concluded that human pop’n would double if they were not kept in check by food supply and economics.

Theory of Natural Selection

1) Organisms are different in some way form each other, and some of these differences are based on heredity.

– Criticized for being biologically deterministic.

2) Organisms over produce.

Darwin reasoned that individuals who have inherit differences that are more adaptive (better enabled to cope with environmental factors to survive and reproduce) will tend to live longer, reproduce, pass these traits on to future offspring.

Called these traits selected in the population.

Saw lots of birds on the island, mainly finches, and lived in groups. They separated from each other, and were different in beak structure.

Differences in beak structure evolved from natural selection.
Birds in places with nuts had stronger beaks. The ones that did not, could not break nuts and therefore didn’t survive.
Birds who were in a dessert environment had long beaks, which allowed them to sip nectar from plants.
Interested in turtles and their shells.
Oval shells, dome shaped, and saddle back. Turtles that live on food from the ground would evolve a dome shaped.
Turtles that had areas where food was on bushes, they had to look up and therefore had saddleback shells

This is what is meant by “Survival of the Fittest”. Fitness, in a Darwinian context referred to traits that were best suited to the animals in the environment.

g. People feel like they worry more than they need to. Those who worry more are more likely to survive.
Don’t worry as much  go into dangerous environments.

Evolution is not always physical, in humans we use the opposable thumb as our example of evolution. BUT it is also behavior:

Animals food searching, predator avoidance, etc.
Evolutionary psychology is more complex behaviour as well. In humans, it applies to consciousness, intelligence, sociability, etc.
The adaptive functions of the human hand: it can carry, build, explore. Every organ has a reason and adaptability. The brain evolved as a mechanism from natural selection.

Socio Political Aspects on Darwin’s Theory

“Survival of the fittest”  Phrase by Spencer. Believer in Laisse faire philosophy (right wing extremist) – Evoked Darwinian theory to say that competition is the natural order of things. – Government should not interfere with this natural order.

BUT this is flawed

1) Naturalistic fallacy: mistaken belief that what is natural is also what is good or right. Confusion between what is and what ought to be.

Ex. Death, disease, pain, loneliness.

Science deals with what IS, but not necessarily is ought to be. Not a rationale for the order of things.

Natural but not good moral right.
What IS: from your brain. What ought to be: your heart. Sometimes they coincide, and sometimes they do not.

Applying the theory to society

– Led to social Darwinism. Applying the theory of Darwinian evolution to society. Theory does not give to the moral sense always, but sometimes it does like empathy

2) What is natural is immutable  unchangeable.

This isn’t necessarily a rule, you can change some things. This is NOT valid statement.

E.g. Marx – fan of Darwin’s theory, and wrote that Darwin’s theory is the basis of natural history and socialism.

Marx assumed that you can change this behaviour to have the correct socio-economic system.

Why does evolution need Darwin?

All sciences share the same goal  understand the cause of things.
There are proximate causes, or ultimate causes, which are causes that are not immediate. Ex. Why are you here (class is schedules [proximate]) or I like psychology (ultimate).

Most people like sweet things  why? They activate certain end organs of your tongue (Ultimate) or they taste good (proximate).

We were vegetarians at the start, and we ate the right fruit which gave us the favorable like towards sugars.
If you liked bitter, it is possible that they got sick from eating the wrong fruits.

Psychology focuses on Ontogenetic causes: pertains to development within a single individual, within their lifespan. From embryo to death.

Ignore phylogenic development, which is your genetic development. Everything before conception, with genes and evolution.

 Psychology tends to ignore this.

Ex. They spend time on human family dynamic. No where do they question the ultimate question like why do people live in families in the first place?

Some species live in families, and some do not.

It is ultimate causality that is studied in evolutionary psychology.

Psycho-linguistics

Language begins and ends in ontology. How to they go from babbling to words? No attempt to incorporate the ultimate question which is why we have language in the first place??
There are different communication patterns. How and why do communication systems develop?
Teach this to chimps, and this purpose was communication, thought it was not innately learned.

Being a proximate or ultimate is not necessary, they all have their special aspects. There is a dichotomy between the 2.

We need to look at both in relation to each other to get a whole picture. Need the how as well as the why to understand something. Proximate causation is primitive thinking.

Why did sex evolve? In comparison to the less sexual ways (like splitting cells). You lose half your genetic data.

Asexual preceded sexual reproduction, so why did it evolve?
Psychologists might say that it is a primary drive. This is a primitive explanation.
Always be limited if you stay unaware about the ultimate causation.

Sex drive decreases after the first year, or after a child. WHY? Better chance of survival if you have offspring, and it allows the pair to focus time/energy/attention on the offspring. Males drop in T after the child is born so they are focused on a child.

Many say that culture is a big determinant of our behaviour, not just our evolutionary past. But they say that we do these things, and that’s why we have a big brain. We developed opposable thumbs because they enabled us to be better tool makers.

We have a big brain, but must talk about how it adapted/evolved.

Saying that something is based on culture is NOT SCIENTIFIC. Theory of Culture has no explanatory values for behavior, unless you are looking at cultural traits.

Psychology will never function at the level of biology, because it does not serve to the ultimate question, but only the proximate.

Darwin had reservations before presenting his theory.
Natural selection is a process that works very slowly, and depends on chance events. Depends on environmental change ex.  Giraffe’s long necks reaching food on higher levels of the tree.

Opposing to Darwin’s theory. (Or more feasible)

Earth was 6 million years old, rather than 4.5 billion years old
Mechanism of inheritance  offspring are born with the attributes of the parents. Mendel: discovers than would resolve the blending question. Inheritance was a matter of particulate.
Grew peas. He either got round or wrinkled peas, so he dispensed the blending theory. They always came out in 3:1. How does this happen?
Dominant and recessive trait. The gene is the unit of heredity.
They are passed on as intact, discrete, articulate entities. Any evolutionary advantage an animal has is INTACT, not blended. Not blended backwards.
He was aware of Darwin’s research.

Blending theory: there was a blending of the protoplasm and that’s how a child acquired their parent’s attributes.

Took till the 1930s until someone used natural selection in terms of genes and traits.

 “The synthetic theory of evolution” It syntehesized Darwin and Mendel’s theory of evolution.

Selection is no longer limited to individual, it is spoken off to genes. It is survival of the individual’s genotype. Not the phenotype and traits, but the genotype. The gene
It explains parenting behaviour. Genes not only enable to survive, but to be good parents as well.
The genes to be good parents, your offspring will get this gene and give it to their offspring as well.
Behaviour is passed on, not only the phenotype.

Genes are no longer limited to the individual, it is also the parenting behaviour. There are genes for good parenting, and these genes will emerge to offspring later on.

 Explains why parents give so much time to their children. It is related to their own survival.

Natural selection needs variation, and genetically based differences between individuals.

What are the sources of variation?  nature and cause of variability

 MUTATION

There are random changes in gene structure, and this is the primary mechanism of evolutionary change.
BUT mutations are not very frequent, and most mutations are deletrious.

 The process of sexual reproduction

Every cell as 23 pairs of chromosomes, except the sex cells. When the M and F cells unite, there are 23 for each that constitute the offspring.
Inherit different combinations from the parent cells, when the gametes unite.

 It contributes to variation, and variation is the basis of natural selection. It does still seem limited in the basis of variation.

A discovery in the 1930s has an answer to this dilemma  sexual reproduction shows more variation than you would expect. – RECOMBINATION

 Gene shuffling, recombination, cross-over phenomenon. Happens in miosis. Pairs of chromosomes and germal cells split to form a GAMETE (sex cells)

The discovery is that just prior to the split (the germ cell), they swap parts randomly.
What this provides is an infinite variation from one generation to the cell. Every gamete in your body is different from every other.
One generation could have limitless offspring, and would have to have 10 to a thousand to have the same one.

Crossover has replaced mutation as the source of variation.

There are 3 major kinds of natural selection

Directional selection: evolutionary change meets the different types of species. Drives change
Stabilizing selection: leads to greater specialization and homogeneity within a species. Have an ecological niche, and specialization in that niche, and then optimal levels in that adaptation. Ex. Cockroaches. Occupy a stable niche, and develop greater selection, and then maximum adaptation.
Disruptive: natural selection is at 2 ends of a continuum. Happens in pack animals. Dominance or submission. Dominant survives the encounters, and submissive animals survive by submising and avoiding encounters.

Why do we have so many extinct species with so much change? Why not just a world full of beetles? “Red Queen Theory”: ‘keep running to stay in the same place’.

Ex. Lions and antelopes. Lions are predators. As the lions hunt antelopes, the slowest ones are eaten, the less cunning are eaten. The fastest will survive. The lions ALSO have to become faster to survive. Both need to be constantly adapting to survive.

Humans have the most amount of change – we do have predators. Viruses. They can contribute to evolutionary change within the human species.

If it were not for our intelligence and mastery of environment, eventually it would lead to physical changes in our environment.
Other people as well. Most of human directional selection is assumed to be based in internal competition with other humans. Evidence of interspecies conflict even in earlier time. Another view from sociologists and cultural anthropologists:
Biggest factor in the development of the brain was competition. This is how the brain got so large. (Evolutionary)
Big brain developed with natural selection, but also because it involved cooperation, more than internal competition. Developed more ways of using the environment. More pleasant than developing ways to compete. (Sociologists and cultural anthropologists)

Competition is in our genes.

Less gradual than Darwin said it was. It is dependant more on sudden environmental change. Mayr: called this is the allo-patrick theory. Natural selection that leads to change happens when a small percentage of the pop’n gets separated from the main one. This may be geographic, or social (overcrowding). He called this the isolated population.
The separated sub pop’n is not well adapted to its new environment, and will have rapid directional natural selection.

Punctuated equilibria: put forth by Eldridge and Gould  the most significant evolutionary changes, including the development of a species is episodic. They are in hundreds of thousands of years. Like the Camridian explosion. Period of 10,000 years.

Permian Extinction: 50% of marine creatures became extinct because of the fusion of the land masses, which created shallow waters. Animals who fed on fish in the shallow waters had less food.

Ice Age: cretian extinction – 75 mill. Years ago. A quarter of species were eliminated, the end of the dinosaurs, which opened a way of the rise of the mammals.

Assumes these and many other are the basis of the intense variation we see, and the basis for natural selection.

Also explains why in fossils there is no speciation (the change of one species to another). Species seem to just appear in paleontological evidence, and stay the same until they disappear.
Species do most of their evolving in a very short time after they appear. Most become extinct rather than branching into new species. No missing link, too quick to recognize.

Autralopithicaus Africanus is the first known relative to the human species. No fossil records for the differences in these fossils. But theory is that speciation occurs too quickly to be seen in fossils.

One implication is that our most salient psychological characteristics have been unchanged over the years
Mating, parenting behaviour, intergroup alliances, competition, conflict, territoriality, formation of status hierarchies, etc. you can find in the earliest form of human life.
Understand why people on different ends of the globe have the same traits. We have the same priorities  more same than different.

Murdock (1945): made a list of traits known to exist in every culture in history

Levels of Selection

Monday, September 30, 2013

Theory of science is a conceptual tool. In religion, and philosophy theory is a truth. In science, it is in the form of a testable hypothesis.
Exceptions and contradictions to the theory are more valuable as the things that support the theory.
These lead to revisions to the theory, which lead to new hypothesis, which leads to new data etc.
A good theory is revised until it no longer exists. What does Darwinian theory not explain?  ALTRUISM

Social definition:

Biological definition: any behaviour which enhances the fitness of others at the expense of the helper. – No motivation, or intention.

An individual that produces few offspring is altruistic  every kid you don’t have will leave more resources for others.

Wyn-Edwards: relationship between the amount of food a population consumes, to the degree that the food is replenished/maintained.

The amount of food a population consumes increases with the resources.
Until it reaches the critical maximum  too much pop’n and not enough food. And then the pop’n decreases.

Hunting: weed out the weaker animals, and the stronger ones reproduce. Pass the critical maximum, you wipe out the strong and the weak until the species are destroyed.

Species have evolved behavioural strategies to control their own population. A mechanism kicks in when they reach CM that stifles the reproduction process.

This works through opimization: [LAK] how females control reproduction  how often she lays eggs, how many eggs per season etc. She adjusts her reproduction potential with the size of the flock. If the pop’n is overcrowded, the reproductive system will shut down.

The epiditec display: observe the flock flying at dusk, and the females bird take a consensus about the number of birds in the flock and how to reproduce accordingly.

One study about this in birds: attempt to control the rook size in Scotland. They shot the rooks, and got paid. But this did not work, the females just doubled up on their eggs when they saw there were less birds.

Overcrowding in rats: [Lachoots?] he overcrowded the rats. The females became infertile, ate their young, males became homosexual, and by doing this they optimized.

 Can get optimization in something like a virus: lyxoma virus. Brought into Scotland to control the rabbit pop’n.

It stabilized the pop’n.

Dawkin’s: sneezing is a way of pop’n control. It gets the virus into a new host. What is the physiological response to humans?

What happens to a female when she gets no food? Ovulation shuts down and she does not reproduce.
The difference in sexual preferences in rural and urban pop’n: in rural pop’n where food and shelters is plentiful you get a larger family, younger pregnancies etc.

Another mechanism for pop’n control is

Helpers at the nest: birds will go to other nests and help the babies in that nest.

Of the 15% of women who remain voluntarily childless, tend to be the oldest in large families. – Overcrowded childhood conditions also turn off the switch of wanting children.

Thompson Gazelle: if there is a danger, the first gazelle that sees the danger begins to alert the whole troop and they would flee. You make yourself more vulnerable.

Bees have kamakazee bees that sniff out ones that don’t belong. They kill them but die in the process.

Baboons: will distract the enemy from the rest.

Young men/women in the prime of reproductive life: going to fight a war.

 Nothing in natural selection accounts for this, or making self sacrifices for others.

Individual selection: competition between individuals.

Group selection: competition between groups  a group has an advantage of reproducing compared to another. The individual may be disadvantaged but the group has benefits.  Ex. 5 by 5 basketball (group) vs. one on one (individual)

Misconceptions

Group selection means survival of species: too wide a scope. They do not die for their species. It refers to herds of gazelles, group of monkeys etc.

Does not start in helping the species, but it does start with joining and defending the group which after a while will affect the wellness of a species.
Group selection has to occur in a smaller sphere to be meaningful. It does not preclude individual selection: people who are not altruistic will outlive the altruistic ones.
But this is using a theory of Darwin. Populations that defend their group are more likely to outsurvive those that do not.

Huxley: advocate of group selection to justify strong government control. Work for the group, work for the state.

 May have had group selection because you could not stand the selfishness of individual selection.

Third level of selection:

Kin selection (inclusive fitness): 1960s by Smith.

Fitness is achieved not only by caring for offspring, but also caring for other relatives. The more you help you kids, the more you are preserving your genotype.
Explains the widespread notion of altruism to children. More altruistic to relatives that share more of your genes.

Twice as nice to siblings as you would be to nieces and nephews, cousins etc.

Hamiliton’s theory: non-reproductive castes of insects

Hymenoptera: ants, bees, etc. Are said to be eusocial: he highest order of social order.

Become sterile to help the offspring of the queen. A true form of altruism.
Many hymenopteria were

Heploid/Diploid: males come from non-fertilized eggs. They were strongly related to each other than to their own offspring if they had any.

100% of their genes they share with their father are alike. 50% of their genes with their mother, and share 75% of their genes with their sisters. More related to their sisters than their mothers.

 With inclusive fitness, they became sterile so the queen could generate more.  Fitness is increased by investing in your sisters than your own.

Diploid/diploid: only one set of chromosomes for males.

Multi level selection: all 3 levels can be operated in the individual at different circumstances. Can sacrifice different levels for the group, including your life.

How far does kin selection extend: no farther that second cousins. Others say much farther, and it can account for ethnocentricism.

Natural selection favored the ability to form the most effect and changeable alliances. Also gives you the ability to change alliances as the circumstances change

E.O Wilson: as wars increased and economic downfalls emerged, then ethnocentricism increased.

Fourth level of selection

Gene selection: (Dawkins) – all natural selection operates at the level of the gene. Construct individuals to be designed for their own survival and replication.

Never became a productive theory.
It did not generate more hypothesis. No way of pointing out the genotype, just observing the phenotype.
Most studies are not done by the genotype, but in terms of the phenotype.

Morning sickness: adaptive function. Infant pushing the mother into the fact that she was feeding him potentially toxic food.

Darwin’s Theory of Evolution/Natural Selection

Levels of Selection