Coral Genomics Group,

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1) more individuals are born than survive
Coral Genomics Group, Queensland, Australia
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2) different individuals have different features,
and some of those features are passed on to the
next generation (i.e. the variation is
genetically heritable)
Sagittaria latifolia (AKA duck potato)
Spencer C. H. Barrett Nature Reviews Genetics 3
274-284 (2002)THE EVOLUTION OF PLANT SEXUAL
DIVERSITY
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3) some of these features will help in survival
(or reproduction), so those individuals that
have this feature will end up having more
offspring than those individuals that dont
Favored in habitats that dont last long
(temporary wetlands)
Favored in habitats that are mainly permanent
(stable wetlands)
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4) eventually, every individual in this
population will have this feature. The
population has now evolved (changed)
temporary wetland
permanent wetland
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oldest known evidence of life is over 3 billion
years old! much of this evidence is from blue
green algae (Cyanobacteria)
Photo by J.W. Schopf
Gloeocapsa (modern)
Myxococcoides (850 million years old)
http//coop.bio.ncue.edu.tw/aqua/ algae/
white/cyano/gloeo-kutzing.htm
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the radioactive decay rate of isotopes is used
to determine the age of fossils and rocks
Radioactive parent isotope (atom)
Half-life
Stable daughter isotope (atom)
 
 
 
Carbon-14
5730 years
Nitrogen-14
Potassium-40
1.3 billion years
Argon-40
Rubidium-87
48 billion years
Strontium-87
Uranium-235
700 million years
Lead-207
Uranium-238
4.5 billion years
Lead-206
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The universal tree
from the Sogin Lab, Woods Hole, MA
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among the earliest animal fossils (about 510
million years old)
Bolinopsis a modern- day comb jelly
Fasciculus a fossil comb jelly
Morris SC, Collins DH. 1996. Middle cambrian
ctenophores from the Stephen Formation, British
Columbia, CanadaPHILOS T ROY SOC B 351 (1337)
279-308
http//www.jelliezone.com
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two arthropods, one from over 500 million years
ago, one alive today
photo by George Brooks
Acadoparadoxides briaraeus (a trilobite)
Sphaeroma quoyanum (an isopod crustacean)
courtesy of The Paleo Project (House of
Phacops)
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great great great great great great
great..grandma (and one of her descendants)
http//www.carleton.ca/tpatters/teaching/ intro/c
ambrian/cambrianex32.html
http//www.dc.peachnet.edu/pgore/ geology/geo102/
burgess/burgess.htm
Pikaia, a 535 million year old chordate (left
actual fossil right cartoon)
Amphioxus, a modern-day cephalochordate
Evo-Devo Research Group, U of Oxford