CHPT 25: Origin and Diversity of Life

Question 1

How many eons is geological time divided in?

Answer 1

four eons

Question 2

How many years ago was earth formed and what eon was it?

Answer 2

4.6 billion years ago

Hadean Eon

Question 3

How did early earth change through time?

Answer 3

CO2 levels shifted and affected temperature

water vaporized from molten rock and continental crust formed

earth cooled off over a million years ago

Question 4

How did weathering release soluble ions?

Answer 4

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

Question 5

What are the two supercontinents formed?

Answer 5

Rodinia- Proterozoic Eon

Pangea- Phanerozoic Eon

Question 6

When did life emerge?

Answer 6

in the Archean Eon

Question 7

When are rock fossils created?

Answer 7

organisms buried in sediment

calcium in bone or other hard tissue mineralizes

surrounding sediment hardens to form rock

Question 8

What elements did the early atmosphere have?

Answer 8

Carbon Dioxide
Nitrogen gas
Water vapor
Hydrogen gas

did not have O2

Question 9

What experiment did Miller and Urey do in 1953?

Answer 9

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

Question 10

What was the first genetic material?

Answer 10

RNA and it is why the first organisms are autotrophic

Question 11

Where did earths oxygen come from?

Answer 11

oxygenic photosynthesis

first O2 produced was cyonobacteria(blue green algea)

Question 12

How was the ozone created?

Answer 12

O2 in the atmosphere interacted with UV radiation from the sun

Question 13

What are the three monophyletic domains?

Answer 13

Eubacteria
Archaea
Eukaryotes

Eubacteria and Archae are Prokaryotes

Question 14

What are the six supergroups that identify with Eukaryotic domain?

Answer 14

Chromalveolates 
Rhizaria
Archaeplastida 
Excavata 
Amoeboza
Opisthokonta

Question 15

What made early eukaryotes successful?

Answer 15

compartmentalization

Question 16

What are the sexual reproduction of eukaryotes?

Answer 16

meiosis and crossing over bc it allows for greater genetic diversity for it is not creating new genetic material it is recombining genetic material

Question 17

What is the hierarchical clusters?

Answer 17

Kingdom
Phylum 
Class
Order
Family 
Genus 
Species

Question 18

The Miller Urey experiment demonstrated that

Answer 18

organic molecules could have originated in the early atmosphere

Question 19

Plate tectonics can contribute to

Answer 19

volcanoes and earthquakes
formation of supercontinents
increased weathering and CO2 sequestration

Question 20

Which of the following events occurred first in eukaryotic evolution?

Answer 20

compartmentalization and formation of the nucleus

Question 21

Fossil data indicate that..

Answer 21

life may have originated 3.5 bya but definitely did so by 3.2 bya

Question 22

A global glaciation would be unlikely to occur if?

Answer 22

millions of acres of forest were cleared

Question 23

Although we do no know how early life arose, the following likely happened

Answer 23

Lipids organized to form cell membranes

Question 24

Which bits of evidence would convince you that life originated as early as 3.2 BYA?

Answer 24

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

Question 25

During which times would you expect that geographic isolation would be particularly important in the evolution of life?

Answer 25

the beginning of the Cenozoic era

Question 26

The chloroplasts of brown algae

Answer 26

are surrounded by two membranes