Lecture 13 Flashcards
How does biology differ from math
- highly parallel, no obvious best teaching order
- life on earth had unique history, large measure of chance mixed in
- a different planet would have different biology, but not math
What would happen if aliens visited other Earth-like planets
- none would have same history (no matter how similar physical and chemical conditions)
What does evolution mean
‘unfolding’
How do stars evolve
birth (large and dense enough that gravity ignites nuclear chain reactions) to death (when fuel used up)
How does evolution with stars differ from lifeforms
How did Charles Darwin differ from others and thus is the most famous
none wrote as extensively, as carefully, or with as much insight
where was Darwin’s theory of evolution published? what did it consist of
The Origin of Species
- 5 main parts
(never used the word evolution, just evolve at the end)
What kinds of things did Darwin do as a child
loved natural history and outdoors
- collected insects, birds, plants, rocks
What kind of science was of debate during Darwin’s undergrad? and Tenets of this new science?
geology… of debate
1. world is ancient and constantly changing
2. ongoing change in planet’s landforms/lifeforms = steady, gradual, observable
What was the prevailing belief in England at the time
Earth was relatively young (6000 years previously)… Great Chain of Being
What was the name of the sailing vessel by British Admiralty?
HMS Beagle
- chart coastline of South America
What was Darwin’s unpaid job on the Beagle
naturalist
What did Darwin develop while on the Beagle
- common descent - every group of organisms descended from a common ancestor, with all lifeforms tracing back to single origin
- new species form gradually and steadily according to observable processes still in operation, happens as populations adapt to surroundings
- natural selection - mechanism of adaption whereby isolated populations evolve into new forms.
*Descent with modification
How many books did he write, which one made him famous
10 books after Voyage of the Beagle - made him famous
What allowed him to be wealthy and devote his time to writing and study?
Sizeable inheritance and investment in railroad stocks
What was Darwin’s likely long term ailment
Chaga’s disease, trypanosome transmitted by a ‘kissing bug’ which he was bitten while in South America
How many of his kids died young
2 infants, 1849 a 10 year old daughter (scarlet fever)…
What is natural selection
biological process… holds when certain conditions hold
What are the conditions needed to hold for erosion?
- substrates have differential hardness
- there is movement of wind, water, or ice
Ubiquitous… = important = always at work
What are the conditions needed to hold for natural selection?
- variation
- inherited
- traits affect survival and/or reproduction (fitness)
*ubiquitous = important = always at work
What other important geological processes are there
- big, large, scale, slow phenomena
- sudden, violent events
–> shaped planet
How does geography impact evolution
create places where unique lifeforms evolve
How does planetary scale catastrophes impact lifeforms
- occasionally occurred and changed dominant flora and fauna of the planet suddenly and completely
What are the 5 parts of Darwin’s theory
- world is ancient and constantly changing
- ongoing change of planet’s lifeforms is steady and gradual
- common descent
- new species also form gradually and steadily
- natural selection
*descent with modification
Draw a monophyletic group
Draw a polyphyletic group
Draw a paraphyletic group
Who pursued idea of peppered vs dark moths?
HBD Kettlewell…
First good quantitative demonstration of natural selection operating in nature
What is directional selection draw it
favours one extreme phenotypes, causing average phenotype in population to change in one direction
What is stabilizing selection and draw it
Favours phenotypes near the middle of the range of phenotypic variation, maintaining average phenotype
What is Disruptive selection and draw it
Favours extreme phenotypes at both ends of the range of phenotypic variation
What is Balancing selection, draw it
No single phenotype is favoured in all populations of a species at all times
What are three ways of understanding what is a species
- biological species concept - one or more actually or potentially interbreeding natural populations, reproductively isolated from other such groups
- morphological species - based on differences in morphology
- Lineage species - a terminal twig on a phylogenetic tree
