Chapter 4: Evolution And Genetics Flashcards
A theory of evolution
Charles Darwin (wrote the origin of the species)
Was a materialist did not believe in the non-material mind
*gave the idea of natural selection and fitness
Natural selection
Animals that have certain traits that give them a survival advantage, those genes get passed on to the next generation. Animals that don’t have those beneficial traits will die out
Fitness
The idea that an organism is going to survive and pass on the trait/genes on to future generations; you can’t just survive you also have to pass on our traits
Survival adaptations
Physical traits to help you survive make your chance of survival better
Reproductive adaptations
Gives animals a better chance of passing on their genes, but it is not a useful thing
Intersexual competiton
Usually males compete against each other, for the opportunity to mate with the female
Intersexual selection
When th opposite sex makes their decision usually the female
First brain cell
700 million years ago, awareness of the environment
First brain
250 mya, collection of brain cells, to perform tasks
First primate brain
7 mya beginning of intelligent life
Evolution of modern humans
humans and chimpanzees share a common ancestor about 7 million years ago
-modern humans are relatively recent geological record
-substantial psychological and cognitive changes compared to earlier species
-vocal change and cognitive change
Australopithecus
Our distant ancestor
-first primate to show distinctly human characteristics
-walk on two legs (bipedalism), doesn’t spend all his time on trees, probably as intelligent as a modern chimpanzee
-intelligence judged through fossil tool; tool making and using- they could use tools but could not make them
-making a tool requires more intelligence
Hominids
The earliest human
-Homo habilis (“the Handy human”)
*could make simple stone tools
-Homo erectus (“upright human”)
*on earth for longer than we’ve been on earth; more sophisticated stone tools = higher intelligence
-Neanderthals
*more sophisticated stone tools= higher intelligence
Evolutions of modern humans
-adaptations to changing environment
-bipedalism; allows an animal to move efficiently, walking on all fours restricts ability to move
-change in diet = smaller facial muscles and teeth; cooking meat softens it, which means we do not need big teeth or jaws anymore
-smaller facial muscle and teeth= greater range of vocalization= language (humans are a ale to have sophisticated language; only ones that do this, it also requires incredible cognitive abilities)
- tool making (making a tool from nothing, filling a need), hunting and cooking ( predicting tides), social organization (working in groups)
-from early to modern humans, brain size and cognitive ability increases
Genetics
-every cell in an organisms body contains the genetic blueprint for that organism
-small section of the chromosome is the genes
Genes and behaviour
Genes - protein - expression
Genotype: genetic plan for what is going to happen: physical trait, eye colours (blueprint)
Phenotype: the physical expression of the genotype
What makes up the DNA
Adenine
-Guanine
-Thymine
-Cytosine
A - T C-G They only bond with each other
Genes to proteins
he sequence of bases in a gene determines which amino acids are used to build the specific protein
-amino acids are the building blocks of proteins
-sequences of bases codes for specific amino acids
Bases - amino acids - proteins
DNA
Doesn’t leave the nucleus of the cell
DNA -mRNA - amino acid chain
Transcription
Endoplasmic reticulum translates the mRNA to know what has to be constructed; translated using a ribosome
Codon
Each three bases on mRNA is referred to as a codon, each codon codes for a specific amino acid
Golgi body
Where the proteins are packed in a vesicle and transported to various parts of the cell
Genetic techniques/ trans genetic
Manipulate genotype, the plan so that the phenotype is different
Introduce or remove genes of an embryo
Knock in (genetic technique)
Introduce a gene that was not there before
Knock-out (genetic techniques)
Silence a gene, you prevent it from being expressed
Animal models for human disorders
The mammalian brain is structurally similar across species
Ex. Hippocampus forms long term memories in both rats and human brains
-animal models used to mimic human diseases such as Alzheimer’s and Parkinson’s
Selective breeding
“Maze bright” and “made dull” rats (tested on the memory of the brain)
-manipulate a genome of animals
-breeding animals with preferable genetics (rats who could remember the maze= maze bright)
The human genome project
Completed in 2003
Human gentic code contains less than 30,000 genes
Identifying what these genes are
Identical twins
Monozygotic
Share the same gentic code (one sperm fertilizes one egg, and the zygote, splits in two)
Identical genomes
Minnesota twin study
Identical twins raised apart share many of the same physical and personality traits
Desire to know what is the effect of the environment and what is the genetic code
What was found from this study was that they did share many of the same traits
Behavioural genetics
Behavioural genetics are used to study genetic influence on a host of different behaviours
-learning disabilities and mental disorders
-despite the throng influence of genetics, there is always and effect of the environment
Epigenetics
genes can explain variation between certain traits and behaviours but not all
-a powerful source of individual differences involves the interaction with environment
Epigentic drift
look a molecular level; when you examine identical twins at a young algae you’ll find their genetics are almost identical. If you measure adults traits and at the genetic level, you begin to see differences (differences=epigentic drift) the reason is the different experiences they are having in life
Epigentic mechanisms
ways the plan can be changed)
Histone modification: DNA is coiled around histones, instead of transcription occurring, it is blocked, the DNA does not fully uncoil from the histone. Transcription does occur fully
DNA modification: bases block transcriptions of some of the bases; you don’t produce the protein that was intended to be produces
mRNA modification: ncRNA binds to RNA preventing translation
-critical during development when genes have to turn on and off at precise intervals, to prevent certain genes from being expressed
Environmental effects on the genome
Disease linked to environmental exposures are difficult to track
Different people respond differently
Ex. Some people who smoke never develop lung cancer but some do
