Lecture 6: Evolution, Genes, and Ecology Flashcards
Mutations that arise in what regions of the DNA are often eliminated by Natural selection?
noncoding
If mutations accumulate in noncoding regions at a constant rate, differences in the DNA sequences can serve as what?
a molecular clock
What does a molecular clock do?
It indexes the time at which two species diverged
Large difference imply divergence in the distant ____
past
Small differences in DNA sequences imply a more _____ common ancestor
recent
How are molecular clocks calibrated?
The fossil record and biogeographically with independent data
Phylogenies can help reveal what type of convergence?
Homoplastic
Similar traits have evolved independently in different ____
clades
What can phylogenies illuminate?
The stepwise evolution of complex characters
How do the initial stages of a character evolve?
as an adaptation to some environmental selective pressure
How can we map character transitions onto phylogenies?
using the principal of parsimony
What was used to understand how COVID- 19 spread?
phylogenetic analysis
What did the phylogenetic analysis of COVID-19 show?
that there were at least 9 introductions of the strains
What eon and around what year was the formation of the earth and moon?
The Hadean eon and around 4.5 BYA
What were the eras in the Archean Eon?
- Eqarchean
- Paleoarchean
- Meoarchean
- Neoarchean
What era and eon did prokaryotes appear?
The paleoarchean era in the Archean eon
What era and eon was the oldest fossil found and what was it?
It was in the paleoarchean era in the archean eon and it was a stromalites
What era and eon did the appearance of eukaryotes occur?
The neoarchean era in the archean eon
What eras are in the Proterozoic eon?
Paleoproterozoic
mezoproterozoic
neoproterozoic
When was the first multicellular life found, name the era and eon?
The Neoproterozoic era in the proterozoic eon
What eras are in the phanerozoic eon?
- Paleozoic
- Mesozoic
- Cenozoic
What periods are in the Paleozoic era?
- cambrian
- Ordovician
- Silurian
- Devonian
- Carboniferous
- Permian
What happened in the cambrian period?
The first true vertebrates appear
What happened in the ordovician period, and what era is it part of ?
Plants began to colonize land and it is in the palezoic
What happened in the devonian period and what era is it in?
The first animals with four legs evolved and it is in the paleozoic
What happened in the carboniferious period and what era is it?
It is the paleozoic era and the first amphibians developed
What happened in the permian period and what era is it a part of?
Four-legged animals split into mammal-like reptiles and reptiles and it is in the paleozoic era
What period and era did the first mammal appear?
The Triassis period in the Mesozoic era
What period and era did the first bird appear?
The jurassic period in the Mesozoic era
What period and era did the first flowering plants evolve?
The cretaceous period in the Mesozoic era
What periods are in the cenozoic era?
- Paleocene
- Eocene
- Oliocene
- Miocene
- Pliocene
- Pleistocene
- Halocene
What period and era did the first primates occur?
The paleocene period in the cenozoic era
What period and era did the hominis (early ancestors of humans- evolve)?
Miocene period in the cenozoic era
What period and era did the first “modern” humans evolve in Africa?
Pleistocene period and cenozoic era
How is geologic time divided into?
Four eons—> eras—> period
When did no rocks exist?
In the Hadean eon for the first 500-700 million years,
Because the Hadean Earth was pummeled by asteroids which could potentially do what to the oceans?
vaporize
If CO2 levels shift what do they affect?
The temperature
The early atmosphere probably had what type of levels of CO2?
High
What slowly vaporized from molten rock?
water
What weathering convert rock to?
soil
What can CO2 form?
carbonic acid
What is carbonic acid released by?
Bicarbonate ions from rock (HCO3- and Ca2+)
Decreases in CO2 cause a what to Earth’s temperature?
decrease
What are plates?
Earth’s crust in forms of rigid slabs of rock
What is Rodinia?
All continents
What is Gondwana?
All current southern Hemisphere continents
What is Pangea?
all continents formed from Gondwana
What eon did Life emerge from?
Archean eon
What potential year did life occur?
3.7 BYA
What is the Proterozoic eon characterized by?
The formation of Rodinia
When did Rodinia break up?
Before the Phaneozoic eon
What did the Cambrian period show diversification of?
multicellular organisms
What was the Miller- Urey Experiment reproduce?
The early atmosphere
What type of atmosphere did the Miller Urey try to recreate?
a reducing atmosphere rich in hydrogen with no oxygen gas
What did the Miller-Urey experiment find within a week?
That methane gas was converted into other simple carbon compounds
What did Miller Urey conclude from their experiment?
That the key molecules of earth could have formed on early earth
What can be assumed about primitive organism?
They could have been autotrophic or heterotrophic
What are some landmarks in the evolution of metabolism
- oxygenic photosynthesis
- carbon fixation
- nitrogen fixation
What is oxygenic photsynthesis?
Photosynthesis releases oxygen
What is carbon fixation?
photosynthetic organisms turn inorganic carbon into organic compounds
What is nitrogen fixation?
any natural or industrial processes that lead to free nitrogen
What may have been the first genetic material?
RNA
____ bubbles could increase the probability of metabolic reactions
lipid
What type of organisms are the first life-forms
single-celled organisms
What are the two main formations of 3.5-3.8 BY rocks that have been found that are interpreted to be biological in origin?
Kaapvaal craton and Pilbara craton
What are stromatolites?
They are mats of cyanobacterial cells that trap mineral deposits
What are stromatolites indirect evidence for?
ancient life
What is the oldest stromatolites?
2.7 Billion years old
What factors affect an organisms’ survival?
Climate and atmosphere
Dramatic shifts in what factors have led to mass extinctions?
climate and atmosphere
Did plants contribute to glaciations?
Yes
What two glaciations did plants contribute to?
colonization of land by plants was followed by gradual cooling and abrupt glaciation 488 to 444 mya
2. vascular plants diversification is concurrent with the second glaciation 400-360 MYA
What are vascular plants?
They are plants that lignified tissues for conducting water and minerals throughout the plants
How did the mitochondria and chloroplast enter early eukaryotic cells?
Endosymbiosis
What are Mitochondria descendants of?
a parasite
What are chloroplasts derived from?
cyanobacteria
What leads to cell specialization?
Multicellularity
What type of organisms constitute about half the biomass on Earth?
Unicellular prokaryotes
Whay multicellularity allow organisms to do?
To deal with environment in novel ways through differentiation
What does multicellularity require cells to do?
TO connect to each other and communicate
What varies among cells to allow specialization?
gene expression
What increases genetic diversity?
sexual reproduction
How does sexual reproduction allow for great genetic diversity?
- Meiosis
- Crossing over
Rapid what occurred durng the Cambrian era?
diversification
When did the first multicellular animals appear?
50 million years following the cambrian explosion
After cambrian radiation what began to colonize terrestrial environments?
plants and then animals
What protected organisms on land by creating the ozone layer?
evolution of photosynthesis
What happened to marine species and terrestrial vertebrates at the end of the permian era?
80% of marine species and 70% of terrestrial vertebrates were extinct
What is the time period for the Triassic period?
251.9 to 201.4 MYA
What is the time period for the Jurassic period?
201.4 to 145 MYA
What is the time period for the cretaceous period?
145 to 66 million years ago
What ended the Mesozoic era?
The K/T mass extinction event
What is the time period for the Paleogene period?
66 to 23 MYA
What is the time period for the Neogene period?
23 to 2.6 MYA
What is the time period for the Quaternary period?
2.6 to 0 MYA
What is the Cenozoic period categorized by?
- rise of mammals
- rise of grasslands
- origins of humans
- sixth mass extinction ongoing
What are the irregularly shaped plates of rock that float on Earth’s semisolid mantel called?
plate tectonic
What is it called when the currents in the mantle cause the plates, and continents to move?
Continental drift
What did Pangea separate into?
Laurasia and Gondwana
What year was Pangea?
240 MYA
What continents were in Laurasia?
North America, Europe, and Asia
What continents were in Gondwana?
South America, Africa, Antartica, Austrialia, India, Madagascar, New Zealand
What year did Laurasia and Gondwana form?
170 MYA
When did Gondwana begin to breakup?
120 MYA
How did Gondwana breakup?
South America and Africa, India and Madagascar and Antarctica and Australia
When did the Rift of Australia vs. India and Madagascar occur?
110 MYA
When did Africa and South America separate and Madagascar and India separate?
90 MYA
When was the KT-Extinction?
65 MYA
When did India collide with Asia?
20 MYA
Species with a ______ distribution live in suitable habitats throughout a geographical area.
continuous
What is disjunct distribution?
closely related species living in widely separated locations?
What two phenomena can create disjunct distributions?
- dispersal
- vicariance
What is dispersal?
the movement of organisms away from their place of origin
What is vicariance?
The fragmentation of a once-continuous geographical distribution by external factors
