Notesale: Turn your study into money

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● All life is fundamentally related to other life
● Three main groups: eukaryotes, bacteria, and archaea
● Phylogeny: a visual representation (a hypothesis) of the evolutionary history of
populations, genes, or species
○ Aka: phylogenetic tree or cladogram
● Anatomy of a phylogenetic Tree

● Characters and Character States
○ A character, or trait, is any genetic, morphological, physiological, developmental,
or behavioral characteristic to be studied (hair color, eye color, etc
...
Homoplasy
● Homology
○ The idea that two organisms share similar traits because it came from a common
ancestor

● Homoplasy
○ Things are similar for any other reason than common ancestor
○ Similar adaptations (evolved separately)
○ Ichthyosaur- water reptilian during dinosaur era

○ Convergent evolution- two organisms independently evolve similar traits
○ Cetaceans- mammals that went back into the water and evolved a fully aquatic
lifestyle
○ *more examples on slides 22 & 23*
(a) Whales are an outgroup
(b) DNA finds whales and hippos share common ancestor
(c) Supports close relationship
(i)
SINEs- short interspersed nuclear elements; sequence of DNA that
will insert themselves into certain genomes of organisms
(1) Transposon
(ii)
Whales and hippos share many of the markers (sharing the four
markers in the pic are not common and that is rare af so it supports
the relationship)

Fossils
● Piece of physical evidence from extinct organisms
● Fossil record- all the fossils scientists have found of a certain organism
○ Evidence of evolutionary past
● Intact fossil
○ Forms when decomposition does not occur and the organic remains are preserved
intact
○ Ex: pollen
● Compression fossil
○ Forms when sediments accumulate on top of the organism and become cemented
into rocks such as mudstone or shale
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The hole that remains
fills with dissolved minerals, which create an accurate case of the remains
○ Ex: ammonite
● Permineralized fossil
○ Forms when organisms decompose extremely slowly
...

● An organism's job
● Lots of empty “jobs”
● There are a number of places in an environment that an organism
can fit into and diversify
● Resource partitioning​: species diversifies and they start to
specialize in different things, eventually becoming different
enough to be different species
■ Evolution of a key innovation
● When the first species evolves a certain adaptation that makes it
successful
○ Ex: flowers, feathers
○ The Cambrian “Explosion”
■ Started 541 mya; lasted 50 my
■ Sudden and very rapid diversification of multicellular organisms that set
up the modern animal groups we find today

● Sponges, mollusks, arthropods, echinoderms, chordates
(vertebrates), etc

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