Which of the following can promote allopatric speciation but not sympatric speciation?
geographic isolation
polypoidy
sexual selection
natural selection
geographic isolation
what was the first genetic material and why?
The first genetic material was most likely RNA, not DNA. RNA plays a central role in protein synthesis, but it can also function as an enzyme-like catalyst. Such RNA catalysts are called ribozymes. Some ribozymes can make complementary copies of short pieces of RNA, provided that they are supplied with nucleotide building blocks.
What hypothesis did miller Urey test
In 1953, Stanley Miller, working with Harold Urey at the University of Chicago, tested the Oparin-Haldane hypothesis by creating laboratory conditions comparable to those that scientists at the time thought existed on early Earth
methods to dating fossils
relative dating - geological time scale using the strata, consistent sequence of historical periods
absolute dating - age is given in years instead of relative terms ( use of radioactive decay)
hadean
4.5 bya to 4 ya
2.7bya
concentration of atmospheric oxygen begins to increase
origin of there solar system and earth on a 60 minutclock
Multicellular eukaryotes evolved by
1.2 bya
single celled eukaryotes on a 60 minuter clock
35 minutes
oxygen revolution in a 60 minute clock
25 minutes
prokaryotes dominated from
3.5 to 2 bya
45 minutes
multicellular eukaryotes
there are more earthquakes at
crustal plate boundaries
multicellular eukaryotes likely evolved by
endosymbiosis
why is the fossil record incomplete
- burial conditions
- rock layer must escape distortion
-fossil ( if preserved) must be re-exposed - needs to e preserved
Oxygen began accumulating at
2.7 bya
35 minutes on a 60 minute clock
single celled eukaryotes
gases formed earth
4.6 bya
crust cooled, solidified
4.1 ya
prokaryotes began = beginning of the fossil record
3.5 bya
Non living -> living
4 steps
1.) abiotic symthesis and accumulation of small organic molecules ( monomers)
e.g nucleotides, amino acids
2.) joining of monomers into polymers
e.g proteins and nucleic acids
- needed to be autocatalytic = the reaction product is the catalyst for the reaction
3.) aggregation of macromolecules into “ protobionts”
- exhibit some characteristics of “ life”
4.) origin of heredity
Self-replicating molecules
May have been RNA based at first
the miller Urey experiment
Wanted to test the OH theory of early earth.
Found organic compounds resulted and some amino acids.
Inherit variability
Competition for monomers to replicate
Struggle to aqcuire molecules required
