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Lecture 8

BIOL 1F90 Lecture 8: BIOL 1F90 lecture 8 winter 2016

Biological Sciences
Course Code
Fiona Hunter

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Wednesday, January 20, 2016
BIOL 1F90, winter
Lecture 8
-fundamental similarity due to descent from a common ancestor
Anatomical Homology
-same set of bones in limbs of modern vertebrates has undergone evolutionary change to
be used for many dierent purposes
-homologous structures are derived from a common ancestor
-vestigial structures are anatomical structures that have no apparent function but resemble
structures of presumed ancestors
-ear wiggling muscles, tail bone, embryonic gill ridges
Developmental Homology
-species that dier as adults often bear striking similarities during enbryomic stages
-presence of gill ridges in human embryos indicates that humans evolved from an aquatic
animal with gill slits
-human embryos have long bony tails
Molecular Homology
-similarities in cells at the molecular level indicate that living species evolved from a
common ancestor or interrelated group of common ancestors
-all living spices used DNA to store information
-certain biochemical pathways are found in all or nearly all species
-the same type of gene is often found in diverse organisms
-P53 plays a role in preventing cancer
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