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Final Exam Notes

Course Code
BIOL 3466B
Study Guide

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1. Macroevolutionary Patterns
Transitional fossils are evidence for macroevolution
» Transitional fossils document the past existence of species displaying
mixtures of traits typical of what are today distinct groups of organisms.
Radiometric dating is a method of measuring the ration of parent isotope to
daughter isotope in a rock sample since unstable isotopes emit particles at a
constant clock-like rate
» Igneous and metamorphous rocks only
» Age of rock = (# of half-lives that have elapsed)(# of years it takes for a half
life to elapse)
» Potassium argon method half-life of potassium = 1.3billion years
Cambrian: 543 mya 495 mya
» Rapid diversification and appearance of almost all animal phyla
» Algae abundant, marine invertebrate diversity
» Climate not well know, prob warming from cold, ice covered
» Ice melts, ocean levels rise, oceans cover much of N.A.
Ediacaran Fauna: 565-544 mya
» There is increasingly strong evidence that small-bodied bilaterally
symmetric animals were present prior to the Cambrian explosion
Burgess Shale Fauna: 520-515 mya
» Compared to animals present earlier in the fossil records, the hallmarks of
the Cambrian fauna are:
A dramatic increase in body size
Origins of hard body exoskeletons
Origins of complex body parts like limbs

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Diversification in basic body shapes and organization
» Most of the animal phyla living today make their first appearance in the
fossil record during the Cambrian
Phylogeny and morphology
» The bilaterally symmetric animals (Bilateria) have three embryonic tissue
types. Most of the bilaterians can move efficiently using a hydrostatic
» Within the bilateria the protostomes and deuterostomes form distinct
What really exploded during the Cambrian was not lineages but morphologies
and ways of making a living
The leading hypothesis to explain the Cambrian explosion is based on a
dramatic rise in atmospheric oxygen concentration, which would have made
higher activity levels and more rapid growth possible
Adaptive radiation occurs when a single or small group of ancestral species
rapidly diversifies into a large number of descendent species that occupy a wide
variety of ecological niches
» A lineage can diversify into many different species with divergent ways of
life in response to
The availability of new habitats and resources
A newly evolved morphological trait that allows individuals to
exploits resources in a new way
Although some lineages show rapid morphological change at speciation
followed by stasis, this is not the predominant pattern in the history of life
» Punctuated equilibrium
Although it might appear static, morphology in a lineage may actually fluctuate
over time around a long-term average
2. Quantitative Genetics
Natural selection is a process that produces descent with modification, or
The theory of evolution by natural selection is testable
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