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Lecture 7

BIO SCI 94 Lecture 7: Week 3 Lectures 7-9


Department
Biological Sciences
Course Code
BIO SCI 94
Professor
Nancy Aguilar- Roca
Lecture
7

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LECTURE 7
1.25.19
Phylogenies
Why study them?
Forensics
Answering biological questions
Vertebrate phylogeny
Parsimony
fewest steps
Synapomorphy
Animals with only one difference are related
Some traits (such as backbone) are not useful when figuring out difference
between species
If all animals have the trait→ it is the least useful
Polytomy
Three branches coming off of one point
Monophyletic group
All descendants of a common ancestor
Polyphyletic group
Unrelated organisms descended from one or more ancestor
Paraphyletic group
Includes an ancestor but not all of its descendants
“Something is left out of a group”
Homology vs. homoplasy
Homology
Similar characteristics emerged from common ancestry
Results of divergent evolution
Homoplasy
Similar characteristics that did not emerge from common ancestry
Results from convergent evolution
Where did whales come from?
Relationship to hippo-like ancestor supported by…
Fossils
Anatomy
Development and embryology
Paleoecology / sedimentology
DNA / Genetics
Geology and Fossils
Precambrian
1. Origin of life
2. Origin of photosynthesis ( & O2 production)
3. Origin of eukaryotes
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4. Origin of multicellular animals
LECTURE 8
1.28.19
Fossils and Geology
1. Earth is built with plates
2. Plates move and may collide or split apart
3. Affect habitats and climate
4. Creates opportunities for speciation
Adaptive radiation (Anole lizards)
1. Monophyletic
2. Speciatied rapidly
3. Ecologically diverse
Habitats
Ex. trunks, twigs, crowns, ground
Foods
Appearance
Behaviors
Anole lizard experiment
Does the presence of the curly-tailed lizard (predator) affect the perch height of
the trunk-ground anoles?
Experimental group: the perch height was increased with the presence of
their predators
What will happen to the % of anoles on the ground over several months in the
control (no predators) and the experimental (with the predators)?
Control: % of anoles on the ground will remain constant over time
Experimental: % of anoles on the ground will decrease over time
Cambrian Explosion: ultimate adaptive radiation
Enough O2 for
Multicellular
Tissues
Structures
Led to....
Arms
mouth/head
New habitats
Swim
Crawl
Burrow
Internal skeleton
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