envs lecture 2 Flashcards
who talked about evolution pre-darwin
plato and aristotle
what is one of the big questions in evolutionary biology
how to explain variation in nature, within species, etc.
what is concept of eidos
‘form’ or ‘idea’ or ‘essence’
give example of essentialism
horses have an immutable (fixed/unchangeable) properties, but each individual has its imperfections
what is essentialism/pre-darwinian view
variation is accidental imperfection
where does this pre-darwinian view come from
from a perception of creationism; idea that life was created by an all powerful being, all life was perfect
basically what did pre-darwinians think
variation is imperfection
what happened in 18th century w/r to thinking of evolution
profound changes in thinking about nature and history of earth
uniformitarianism
present is the key to the past
who came up w/ uniformitarianism
geologists James Hutton, Charles Lyell
what is catastrophism
sudden violent and short-lived events were responsible for current state of the earth
what did Hutton and Lyell argue
the same geological processes operated in the past as in present, and therefore geological data could be explained by causes that we observe
what contrasts w/ uniformitarianism
catastrophism
describe catastrophism
ties the current state of the earth to sudden violent and short-lived events like volcanism, or events like asteroid impacts
describe reality w/r to uniformitarianism
both ongoing events AND catastrophic events play a role in evolution
georges cuvier
animal anatomist, studied fossils
what was cuvier among the earliest to recognize
fossil forms were likely extinct
why was this idea of fossils forms being extinct a hard concept to grasp
didn’t match the ideas of the day that all organisms were part of the ‘great chain of being’,
great chain of being
scale/ladder of nature created by god
what did jean-baptiste pierre antoine de monet, chevalier de lamarck do
developed theories of phenotypic evolution and speciation
was lamarck correct
nah
define lamarck’s theory of phenotypic evolution
inheritance of acquired characteristics —> traits acquired during the course of an individual’s lifetime were passed on to offspring
example lamarck’s theory
lengthening of giraffe’s necks over lifetime would be passed down, or thickening of blacksmith’s arms
inheritance of acquired characteristics
changes in individuals within a generation passed onto next generation
natural selection
variation among individuals, certain variants more likely to survive and pass traits onto next generation
lamarck’s theory of speciation
species originate by spontaneous generation, have not originated from common ancestors
who was pre-darwin
plato & aristotle, james hutton & charles lyell, georges cuvier, lamarck
when was Darwin
1859
who was darwin
1809-1882, voyage of the beagle, accomplished naturalist
what inspired Darwin
Thomas Malthus’s that argued rate of human pop growth is higher than rate of increase in food supply, leading to famine
what did malthus inspire darwin to think
inspired his ideas about struggle for existence
when did darwin read malthus
1838
describe process of publishing origin of species
after formulating his theory, spent 20 yrs trying to sort out flaws, then finaly published it
when did he publish origin of species
1859
why did he take a long time to publish origin of species
b/c he knew it would be controversial
two major theses of origin of speceis
- descent w/ modification (evolution), 2. causal agent of evolutionary change (natural selection)
describe the process of nat selection as a cause of evolution through generations
early in gen 1: heritable/genetic differences in phenotype
later in gen 1: natural selection acts
generation 2: evolutionary change via natural selection
how are the peppered moths example of nat selection/evolution
variation in phenotype, traits are heritable, etc.
what is the variation in phenotype
melanic and non-melanic peppered moths
describe these phenotypic traits
heritable; have a genetic basis
describe peppered moths
white form; soot from coal burning caused black form to be popular, then white form became popular after coal burning decreased
what is suggested agent of selection w/ peppered moths
predation by birds
descent w/ modification
describes biological evolution
natural selectoin
differential survival or reproductive success of classes of entities that differ in one/more characteristics
criteria for natural selection
differences, that are inherited (must be inherited for evolution by natural selection)
1st component of darwin’s book
evolution
what is evolutoin
characteristics of lineages of organisms change over time
what is 2nd component of darwin’s book
common ddescent
what is common descent
all life could be portrayed as one great family tree (tree of life, a metaphor
was common descent a new or old view of evolution
radically new
what is 3rd component of darwin’s book
gradualism
what is gradualism
proposition that differences b/w radically diff organisms have evolved incrementally, small steps thru intermediate forms
what is 4th component of Darwin
population change
what is population change
thesis that evolution occurs by changes in the PROPORTIONS of individuals within a population that have diff inherited characteristics b/c of differential survival and reproduction (natural selection)
what is 5th component
natural selection
what is natural selection
darwin; changes in proportion of individuals w/ diff characteristics are caused by differences in their ability to survive and reproduce; such changes result in evolution of adaptations
who independently conceived natural selection
Alfred Russell Wallace
was evolution a new theory
no
was common descent a new idea
yeah
was gradualism (slow incremental change) a new idea
yeah
what are adaptations
traits that improve an individual’s chance at survival and reproduction in a given env.
what was the Darwinian view of evolution
variation is adaptive, natural selection acts on that variation
describe pre vs. post darwinian view of variation
before they would see this variation as imperfection; Darwin & Wallace would say the variation is adaptive, natural selection acts on this variation
who was Wallace
british naturalist, traveled the world collecting specimens; came up w/ same idea as darwin: Evolution happens thru natural selection
what did wallace spur darwin to do
publish origin of species
what was wallace called
father of biogeography
wallace’s line
major biogeographic barrier b/w australasia and asia
wallace effect
explanation for speciation via ‘reinforcement’
what is biogeography
subfield of evolutionary biology; field that focuses on geographic distributions of organisms
what’s up w/ Wallace’s line
barrier, noticed that many groups of organisms were only found north or south of the line