Chapter 23

Question 1

What’s absolute dating?

Answer 1

absolute dating is when the age of a fossil is given in YEARS rather than in relative terms like “before” or “after”

Question 2

What’s radiometric dating?

Answer 2

radiometric dating is when you determine how old a fossil is based on how much RADIOACTIVE ISOTOPES have decayed.

Question 3

What’s the half-life?

Answer 3

the half-life is the RATE OF RADIOACTIVE DECAY

Question 4

What does the half-life measure?

Answer 4

the half-life measures how long it takes for fifty percent 50% of the parent isotope

Question 5

The geologic record divide’s Earth’s history into what eons? (4)

Answer 5

oldest to youngest

1. Haldean
2. Archaean
3. Proterozoic
4. Phonerozoic

Question 6

What time periods does the youngest eon, Phonerozoic include?

Answer 6

oldest to youngest

1. Paleozoic
2. Mesozoic
3. Cenozoic

Question 7

What’re stromatolites?

Answer 7

Stromatolites are layered rocks that form when certain prokaryotes bind thin films of sediment together

Question 8

Wha’s the plate tectonics theory?

Answer 8

the plate tectonics theory says that continents are plates on Earth’s crus that float on the hot, underlying part of the mantle.

Question 9

What’s continental drift?

Answer 9

continental drift is when the mantle moves, causing the plates to move as well

Question 10

What’s Pangea?

Answer 10

Pangea is all of the continents attached together

Question 11

What’s mass extinction?

Answer 11

mass extinction is when a lot of species become extinct

Question 12

What’s the Permian mass extinction?

Answer 12

the Permian mass extinction killed of ninety six percent 96% of marine animal species

Question 13

How did the Permian mass extinction happen?

Answer 13

the Permian mass extinction happened when Siberian volcanoes erupted

1. increased carbon dioxide levels
2. increased the temperature
3. decreased oxygen levels
4. killed plants and animals

Question 14

What’s the Cretaceous mass extinction?

Answer 14

The Cretaceous mass extinction killed all DINOSAURS

Question 15

How did the Cretaceous mass extinction happen?

Answer 15

the cretaceous mass extinction happened because of an asteroid or comet colliding with earth

Question 16

What’re the consequences of mass extinctions? (3)

Answer 16

consequences of mass extinctions:

1. decreases diversity
2. kills of species or lineages with advantageous or novel features
3. leads to ADAPTIVE RADIATIONS.

Question 17

What’re ADAPTIVE RADIATIONS? (very important)

Answer 17

adaptive radiations are when new species develop new adaptations, allowing them to fill different ecological roles left by extinct species

Question 18

What’s heterochrony?

Answer 18

Heterochrony is an evolutionary change in the RATE or TIMING of development

Question 19

What’s paedomorphosis?

Answer 19

Paedomorphosis is when an organisms body development hasn’t caught up to its sexual development

Question 20

What’re HOMEOTIC genes?

Answer 20

homeotic genes control the PLACEMENT and SPATIAL organization of BODY PARTS

Question 21

What’re HOX genes?

Answer 21

how genes provide POSITIONAL information in an ANIMAL EMBRYO

Question 22

What’s evolution like?

Answer 22

evolution is like TINKERING

Question 23

Why’s evolution like tinkering?

Answer 23

evolution is like tinkering because it’s a process in which new form arise by slightly modifying existing forms

Question 24

What’s EXAPTATIONS?

Answer 24

exaptations are structures that evolve for one specific function but become co-opted for ANOTHER FUNCTION.