Psychology 2220A/B Chapter Notes - Chapter 8: Glossopharyngeal Nerve, Geopolitics, Adenine
2 May 2018
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LECTURE 8: EVOLUTION PART 1
- Understanding Evolution analogy
o Trying to understand the brain without understanding how it evolved is
like trying to understand geopolitics without knowing any history
- Why are the Cranial Nerves a Mess?
o Face-related nerves
▪ Trigeminal (V): mostly sensory facial, some motor (jaw)
▪ Facial (VII): mostly motor, some sensory (taste from anterior
2/3 of tongue)
▪ Glossopharyngeal (IX): sensory (incl. posterior 1/3 of tongue)
+ motor (throat)
o Cranial Nerves:
▪ Control of the face (sensory input, and motor output) there are
at least 3 nerves involved
▪ Why are they such a mess?
▪ Evolution cant go back and start again
▪ Tiny fixes and add-ons
o Craziest Example:
▪ Vagus Nerve:
• One of the branches goes from base of the brain, loops
around the heart and then goes into the voice box
• Goes for a very long distance to move 2 inches
• Controls the muscles that makes sound and breathing
and swallowing
• Inherited from the fish
• Fish don’t have necks
• Direct link from brain to gills in heart
• Evolution cannot start over, must make small changes
to keep going
▪ Why?
• Sensible design in fish
• Brain and heart are close together in fish
• Simplest way to make things work in animals with
longer necks
Basics to know for Evolution:
- Charles Darwin 1809-1882
- HMS Beagal
find more resources at oneclass.com
find more resources at oneclass.com
- Sailed from England south america Australia
- Galapagos Islands
o Animals haven't been interbreeding with other species
o Diversity of finch beaks
o Insects
▪ Smaller longer beaks
o Brains
▪ stubby, stronger
- Diversity within the categories
- The Origin of Species Book
Evolution and Natural Selection:
- Animal with a trait, mutation happens and you get difference variants of
that trait
o Some with the mutations reproduce
o Distribution of traits
o Survival of the Fittest
- VIDEO:
- Regardless of starting point, through the mutation and selection
process you get creatures with increasing “fitness”
DNA:
- Nucleotides = guanine, cytosine, adenine, thymine
o c & g
o a & t
- Mutations
o Darwin didn’t’t know about DNA
o Cell nucleus chromosome DNA nucleotides
o Putting nucleotides into certain order is used to make amino acids and
then amino acids into proteins
- Proteins
- Large, complex molecules
- >50,000 proteins
- All made from ~20 amino acids
- Examples
- Structural proteins
- e.g., actin (in muscles)
- Antibodies
o Enzymes
o Transporters
- e.g., hemoglobin
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find more resources at oneclass.com
- Messengers
o Hormones (e.g., oxytocin)
o Neurotransmitter receptors
- Base pairs amino acids proteins
- Examples
o Structural proteins
- e.g., actin (in muscles)
o Antibodies
o Enzymes
o Transporters
- e.g., hemoglobin: grabs onto oxygen and delivers it to
places in the body that needs it
- Traits and Genes
o Genotype, phenotype
o Dichotomous traits (pea color) vs. continuous traits (skin color)
o Alleles, dominant, recessive
o Genes are sections of chromosomes
- Alleles: types of genes
o Heterozygous: two different alleles
o Homozygous: same two alleles
- Dominant
- Recessive
o Genotype: actual genes (alleles)
o Phenotypes: what the trait is
o A lot of our traits are determined by a series of genes not just one
gene
- Eye colour is one of the exceptions
- In some ways the number of genes we have make sense
- Flu is a simple organism therefore very little genes
- Humans are complex organisms therefore many genes
- Number of genes is some what correlated with complexity but not entirely
- Video about Mice:
- Desert mice
- Mice who live on the light rocks remain light
- Mice who moved to the dark rocks have a darker fur
- DNA changes through:
- Reproduction
- Mutation
- Without mutation, generations would stay consistent
- Mutations happen when DNA divides and replicates
- DNA Cookbook Analogy
- DNA – a “cookbook” with an “alphabet” of 4 letters
- “Recipes” make proteins
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Understanding evolution analogy: trying to understand the brain without understanding how it evolved is like trying to understand geopolitics without knowing any history. Why are the cranial nerves a mess: face-related nerves, trigeminal (v): mostly sensory facial, some motor (jaw, facial (vii): mostly motor, some sensory (taste from anterior. 2/3 of tongue: glossopharyngeal (ix): sensory (incl. posterior 1/3 of tongue) Sailed from england south america australia. Galapagos islands: animals haven"t been interbreeding with other species, diversity of finch beaks, insects, smaller longer beaks, brains, stubby, stronger. Animal with a trait, mutation happens and you get difference variants of that trait: some with the mutations reproduce, distribution of traits, survival of the fittest. Regardless of starting point, through the mutation and selection process you get creatures with increasing fitness . Nucleotides = guanine, cytosine, adenine, thymine: c & g, a & t.
