SCILIVSY 12 Lecture Notes - Lecture 10: Biogeography, Pelvis, Essentialism
19 Jun 2018
School
Department
Course
Professor
!"#$%&'#()*+),-&%.-$)/0$01&'#(
A,#C,#T,#G
○
Bases#used#in#DNA
•
A,#C,#U,#G
○
Bases#used#in#RNA
•
99%#of#all#human#genes#are#present#in#the#mouse,#from#which#we#diverse#
about#75#million#years#ago
○
Ex.#The#mouse#gene#can#substitute#for#the#fruit#fly#gene#in#generating#an#
eye
○
Deep#Homology#(derived#from#a#common#ancestor)
•
Congruence#of#two#different#approaches#to#mapping#the#history#of#life
○
Order#of#evolution:#fish#>#amphibians#>#reptiles#>#mammals
○
INTERMEDIATE#FORMS#DOES#NOT#IMPLY#HALFWAY#FORMS
○
Fossils#and#Phylogeny
•
Ex.#The#Whale#Pelvis:#preset#only#because#whales#are#descended#
from#four-legged#ancestors
§
A#functionless#trait#that#is#only#present#by#virtue#of#descent#from#an#
ancestor#in#which#it#was#functional
○
Vestigial#Organs
•
Whale#caught#with#poorly#formed#hind#limbs#(1920)
□
Results#because#of#mutation#or#because#of#developmental#
anomalies
§
An#ancestral#trait#that#reappears#in#a#descendant#taxon
○
Atavism
•
A#panda's#thumb:#not#actually#a#true#thumb#but#rather#a#modified#wrist#
bone
○
Lousy#Design
•
Species#A#living#in#location#X#gives#rise#to#Species#B#through#
descent#with#modification.#Species#B#must#be#located#close#to#
location#X
□
Due#to#evolution
§
Analysis#of#the#geographical#distribution#of#animals#and#plants#shows#that#
closely#related#species#tend#to#be#found#in#contiguous#(overlapping)#
regions
○
Biogeography
•
20310(&)4'&5)6#7'8'1-&'#(
Variation:#determines#the#competition's#winners
§
Heritability:#the#next#generation#is#enriched#for#favorable#variants
§
Competition
○
Led#to#food/resource#shortages#>#increased#competition□
Due#to#1977#drought
§
In#a#single#generation,#natural#selection#has#shifted#the#mean#bill#size#of#
the#population#(finches)
○
Natural#selection#is#the#inevitable#result#of#"superfecundity"•
Paley#negation:#design#in#nature#is#accomplished#by#a#blind,#purposeless#
process,#rather#than#by#a#purposeful#designer
○
The#focus#has#shifted#from#the#ideal#to#the#population
§
950)2-.4'(:;-$$-10)&50#.+)is#a#departure#from#traditional#essentialist#
views#of#nature#(WHAT#IS#THIS?#2'"'(0)1.0-&'#(<<<=.#Instead#of#seeing#
variation#as#a#mere#deviation#from#an#ideal,#Darwin#elevated#it#to#a#new#
status#as#the#raw#material#of#evolutionary#change
○
Darwin-Wallace#Revolution•
,-&%.-$)/0$01&'#(
Lecture'#10
Friday,#October#28,#2016
1:27#PM
Document Summary
99% of all human genes are present in the mouse, from which we diverse about 75 million years ago. The mouse gene can substitute for the fruit fly gene in generating an eye. Congruence of two different approaches to mapping the history of life. Order of evolution: fish > amphibians > reptiles > mammals. A functionless trait that is only present by virtue of descent from an ancestor in which it was functional. The whale pelvis: preset only because whales are descended from four-legged ancestors. An ancestral trait that reappears in a descendant taxon. Results because of mutation or because of developmental anomalies. Whale caught with poorly formed hind limbs (1920) A panda"s thumb: not actually a true thumb but rather a modified wrist bone. Analysis of the geographical distribution of animals and plants shows that closely related species tend to be found in contiguous (overlapping) closely related species tend to be found in contiguous (overlapping) regions.
