History of Life

Question 1

What is the oxygen revolution?

Answer 1

This is when an influx of oxygen entered the atmosphere in a short time period of time, demonstrating the dynamic history of the Earth
Caused the extinction of many prokaryotic groups

Question 2

What is macroevolution?

Answer 2

The broad pattern of changes above the species level

Question 3

What were the conditions on Young Earth like?

Answer 3

• Earth formed about 4.6 billion years ago
• Until about 4 billion years ago, bombardment by rocks and ice likely vaporized water and prevented seas from forming

Question 4

How was life likely originated?

Answer 4

• Abiotic synthesis of small organic molecules (amino acids)
• The joining of these smaller molecules into macromolecules (proteins)
• The packaging of these macromolecules into protocells
• The origin of self-replicating molecules that eventually made inheritance possible

Question 5

What does the fossil record do, and what are some of its flaws?

Answer 5

shows changes in kinds of organisms on Earth over time
* biased in favor of species that existed for a long time, were abundant, and had hard parts

Question 6

What are the eons in order of oldest to newest?

Answer 6

Hadean -> Archaean -> Proterozoic -> Phanerozoic

Question 7

What are the eras from the Phanerozoic eon in order of oldest to newest?

Answer 7

Paleozoic -> Mesozoic -> Cenozoic

Question 8

How long ago was prokaryotes were on the Earth?

Answer 8

Earth’s sole inhabitants for more than 1.5 billion years; first one was found 3.5 billion years ago

Question 9

The first eukaryotes

Answer 9

Oldest fossil: 1.8 billion years ago
endosymbiosis- mitochondria and plastids were formerly free-living prokaryotes that begun to fuse with larger cells to create eukaryotic cells

Question 10

Explain the origins of multicellularity

Answer 10

Oldest: 1.2 BYA
larger and more diverse multicellular eukaryotes don’t appear in the fossil record until 600 MYA.

Question 11

What is the Cambrian explosion?

Answer 11

Refers to the sudden appearance of fossils resembling modern animal phyla within a 10 million year window of the Cambrian period
* First evidence of predator-prey interactions in the fossil record

Question 12

When was the origin of modern humans?

Answer 12

200,000 years ago

Question 13

How does speciation and extinction rates influence diversity?

Answer 13

Patterns of diversity have been influenced by large-scale processes, such as plate tectonics, mass extinctions, and adaptive radiations

Question 14

What are plate tectonics

Answer 14

Earth’s crust is composed of plates floating on its mantle
Tectonic plates move slowly through the process of continental drift

Question 15

What are the consequences of continental drift?

Answer 15

*alters the habitat in which organisms live
*a continent’s climate can change as it moves north or south
*separation of land masses can lead to allopatric separation

Question 16

What is mass extinction

Answer 16

When the rate of extinction has increased dramatically
Result of disruptive global environmental changes
In each of the five mass extinction events, 50% or more species became extinct

Question 17

What was the Permian mass extinction?

Answer 17

Happened 251 MYA, defines the boundary between Paleozoic and Mesozoic era
Caused by volcanoes, 96% of marine species went extinct

Question 18

What was the Cretaceous extinction?

Answer 18

Happened 65 MYA, defines the boundary between Mesozoic and Cenozoic
Half of all marine species and many plants/animals went extinct (including dinos)

Question 19

What is adaptive radiation?

Answer 19

rapid evolution of diversely adapted species from a common ancestor
may follow mass extinctions, the evolution of novel characteristics, and the colonization of new regions

Question 20

What is an example of global adaptive radiations?

Answer 20

Mammals underwent adaptive radiation after the extinction of dinosaurs, allowing mammals to expand in diversity and size

Question 21

What is an example of regional adaptive radiation?

Answer 21

Can occur when organisms colonize new environments with little competition
ex: Hawaiian islands organisms

Question 22

How does macroevolution also allows for the study of traits?

Answer 22

*suggests that traits evolve by tinkering-new forms arise by the slight modification of existing forms
*natural selection can only improve a structure in the context of its current utility

Question 23

What are some evolutionary novelties?

Answer 23

Complex eyes have evolved form simple photoreceptive cells independently many times

Question 24

Why is it important to look at evolutionary trends?

Answer 24

Fossil records can be misleading, and evolutionary trends don’t imply an intrinsic drive toward a particular phenotype