Chapter 25: The History of Life on Earth

Question 1

What is MACROEVOLUTION? how is it often revealed?

Answer 1

evolutionary change above the species level

often revealed through the fossil record

Question 2

What are the 4 main stages that lead to the creation of the first cell?

Answer 2

1. monomer (the abiotic synthesis of small molecules such as amino acids and nitrogenous bases)
2. polymer (the joining of these small molecules into macromolecules such as proteins and nucleic acids)
3. protocells
4. cells that were self replicating (DNA)

Question 3

What are PROTOCELLS?

Answer 3

droplets with membranes that maintained internal chemistry that was different from that of their surroundings

Question 4

What is RADIOMETRIC DATING?

Answer 4

a technique of dating rocks and fossils based on the fixed rate of radioactive decay

Question 5

What is a HALF-LIFE?

Answer 5

the time required for 50% of the parent isotope to decay

Question 6

How old is a fossil that has 1/4 of the parent isotope left?

Answer 6

multiply 5730 (the half life of carbon) by 2
1 to 1/2 is the first half lie
1/2 to 1/4 is the second half life

Question 7

What is a PROKARYOTE cell?

Answer 7

a type of cell lacking membrane bound organelles

Question 8

What were the first cells to develop?

Answer 8

prokaryote

Question 9

How did prokaryotes obtain energy?

Answer 9

the sun

Question 10

What did the increase of prokaryotes using the suns energy lead to?

Answer 10

the oxygen revolution

Question 11

What is a eukaryotic cell? how did they evolve

Answer 11

a cell that has membrane bound organelles, evolved through endosymbiosis and infolding

Question 12

What is ENDOSYMIOSIS?

Answer 12

a relationship between two species in which and organism lives inside the cell to cells to another organism

Question 13

What did EDOSYMBIOSIS give rise to?

Answer 13

chloroplasts, mitochandra, and plastids

Question 14

What is serial endosymbiosis?

Answer 14

a hypothesis for the origin of eukaryotes consisting of a sequence of endosymbiotic events

Question 15

What did infolding lead to?

Answer 15

nuclear membrane and ER

Question 16

Why is multicellularity important?

Answer 16

lead to specialization

Question 17

What is the hypothesis for multicellularity?

Answer 17

unicellular organisms became sticking together in colonies known as a volvox

Question 18

What was the CAMBRIAN EXPLOSION and why is it important?

Answer 18

the Cambrian was a time about 525-535 million years ago in which many present day phyla emerged in a short period of time

important because this is where we first see hard bodied, large animals and HUNTERS EMERGE along with PREY DEFENSE

Question 19

When was the colonization of land for Fungi, anthropods, and plants?

Answer 19

420 million years ago

Question 20

When was the colonization of land for tetrapods?

Answer 20

365 million years ago

Question 21

What is CONTINENTAL DRIFT?

Answer 21

the movement of plates floating on the earth’s crust

Question 22

What does continental drift promote?

Answer 22

allopatric speciation on a grand scale

Question 23

What was the importance of the PERMIAN MASS EXTINCTION and around when did it occur?

Answer 23

most expensive extinction (96% all species wiped out)

250 m.y.a

Question 24

What was the importance of the CRETACEOUS EXTINCTION?

Answer 24

most famous and well studied extinction (wiped out dinosaurs but placental mammals start flourishing right after)
65 m.y.a

Question 25

What are ADAPTIVE RADIATIONS?

Answer 25

a period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological niches in their communities

Question 26

What is an example of WORLDWIDE ADAPTIVE RADIATION?

Answer 26

mammals underwent dramatic diversification/adaptive radiation after the extinction of the dinosaurs

Question 27

What are the 3 types of mammals (cynodont)?

Answer 27

placental
monotremes
marsupials

Question 28

what is an example of REGIONAL ADAPTIVE RADIATION?

Answer 28

the silverswords alliance (the plants of hawaii that are all different but came from the same plant - tarweed)

also house flies

Question 29

what often initiates REGIONAL ADAPTIVE RADIATION?

Answer 29

the founder effect

Question 30

What are the 3 trends seen through the fossil records of horses?

Answer 30

1. larger
2. complex molar teeth
3. fewer toes

Question 31

Evolution is like a mechanic not and engineer. T or F?

Answer 31

T

Question 32

What is an example of evolution not being goal oriented?

Answer 32

the mollusk eye

from the slides: The mollusk eye illustrates this. Although the mollusk eye is very similar to the vertebrate eye in its complexity, it is actually better because the photoreceptors of vertebrate eyes point backwards causing blind spots. Mollusks’ photoreceptors face forward; thus, they have better eyesight. This illustrates that although both of these animals evolved complex eyes independently, the vertebrate’s eye evolved with what was available, not what is the best design.