CHPT 25: Origin and Diversity of Life Flashcards
(26 cards)
How many eons is geological time divided in?
four eons
How many years ago was earth formed and what eon was it?
4.6 billion years ago
Hadean Eon
How did early earth change through time?
CO2 levels shifted and affected temperature
water vaporized from molten rock and continental crust formed
earth cooled off over a million years ago
How did weathering release soluble ions?
CO2 mixed with water creating carbonic acid
carbonic acid and rain release bicarbonate ions form rock (HCO3- and Ca2+)
bicarbonate and calcium formed calcium carbonate which sequestered CO2 in the ocean
What are the two supercontinents formed?
Rodinia- Proterozoic Eon
Pangea- Phanerozoic Eon
When did life emerge?
in the Archean Eon
When are rock fossils created?
organisms buried in sediment
calcium in bone or other hard tissue mineralizes
surrounding sediment hardens to form rock
What elements did the early atmosphere have?
Carbon Dioxide
Nitrogen gas
Water vapor
Hydrogen gas
did not have O2
What experiment did Miller and Urey do in 1953?
condected experiment that reproduced atmosphere by assembling atmosphere in rich hydrogen with no oxygen, it was placed over water and the temperature was below 100C
it stimulated lightning and within a week methane gas converted into simple carbon compounds
What was the first genetic material?
RNA and it is why the first organisms are autotrophic
Where did earths oxygen come from?
oxygenic photosynthesis
first O2 produced was cyonobacteria(blue green algea)
How was the ozone created?
O2 in the atmosphere interacted with UV radiation from the sun
What are the three monophyletic domains?
Eubacteria
Archaea
Eukaryotes
Eubacteria and Archae are Prokaryotes
What are the six supergroups that identify with Eukaryotic domain?
Chromalveolates Rhizaria Archaeplastida Excavata Amoeboza Opisthokonta
What made early eukaryotes successful?
compartmentalization
What are the sexual reproduction of eukaryotes?
meiosis and crossing over bc it allows for greater genetic diversity for it is not creating new genetic material it is recombining genetic material
What is the hierarchical clusters?
Kingdom Phylum Class Order Family Genus Species
The Miller Urey experiment demonstrated that
organic molecules could have originated in the early atmosphere
Plate tectonics can contribute to
volcanoes and earthquakes
formation of supercontinents
increased weathering and CO2 sequestration
Which of the following events occurred first in eukaryotic evolution?
compartmentalization and formation of the nucleus
Fossil data indicate that..
life may have originated 3.5 bya but definitely did so by 3.2 bya
A global glaciation would be unlikely to occur if?
millions of acres of forest were cleared
Although we do no know how early life arose, the following likely happened
Lipids organized to form cell membranes
Which bits of evidence would convince you that life originated as early as 3.2 BYA?
using transmission and scanning electron microscopy, you find evidence of a carbon based material in what appears to be a cell wall of a fossil isotopically dated as 3.2 BYA
