evolution review
DESCRIPTION
Evolution Review. Do Now: Turn in cladogram labs from yesterday. Part I: Phillosophy of Truth. What is science? Observable, measurable quantities only! Hypotheses require mechanisms (how) with supporting evidence Truth and Logic in Science - PowerPoint PPT PresentationTRANSCRIPT
EVOLUTION REVIEW
Do Now: Turn in cladogram labs from yesterday
Part I: Phillosophy of Truth What is science?
Observable, measurable quantities only! Hypotheses require mechanisms (how) with
supporting evidence Truth and Logic in Science
Negative proof is impossible (Russell’s Teapot, Flying Spaghetti Monster)
Occam’s Razor: the least complex solution to a problem has the highest probability of being correct
Parsimony: measure of complexity. More parsimonious = simpiler.
Part II: Evolution Basics Evolution: how species change over
time. Natural selection: the mechanism of
evolution. the process by which heritable traits that
make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations.
Natural Selection For natural selection to function, there
are 3 requirements Variation Differential mortality heritability
1: Variation For natural selection to work, there must
be a range of characteristics in a population.
2: Differential Mortality Some characteristics or variations allow
an organism to survive and/or reproduce more than others.
3: Heritability The
characteristics that lead to increased survival and reproduction must be able to be passed on to subsequent generations
Types of Evolution Speciation: The evolution of new
species from pre-existing ones Two types of speciation
Phyletic speciation: One species replaces an older one (think fossils)
Divergent speciation: One species evolves into two new species.
Phyletic vs. Divergent Speciation
2 Modes of Evolution Gradual Evolution: small changes over
long periods of time Punctuated Equilibrium: big changes in
short time periods.
Gradualism vs. Punctuated Equilibrium
Fossils Fossil: preserved remains or traces of an
ancient organism. Most are formed by mineralization
(turning to rock) Trace fossil: not the organisms itself, but
from an organism (dung, footprints, etc.) Other fossils: amber, ice, tar
Fossil Geology Sedimentary rock: rocks made of
compressed layers of sediment. Only type of rocks that contain fossils
Fossil Geology Law of
Superposition: Older rocks are found below newer ones, since layers of sediment are deposited over time.
Darwin Charles Darwin proposed the
theory of evolution by natural selection in his 1859 book The Origin of Species.
His evidence came from an expedition around South America on the H.M.S. Beagle.
Most important to his work are the unique creatures of the Galapagos Islands
Representing Change Phylogram (aka cladogram): A diagram
representing evolutionary relationships.
Homologous Structures Homologous structures are similar in
form and composition in different species.
Phylogeny Phylogeny is the relatedness among
different species (note: phylogenetic tree shows phylogeny)
It is based on: Fossil evidence Homology (including genetics)
That’s Evolution Part 1! BIG quiz tomorrow – study this guide!!!