Ch 25.2: History of Life on Earth II: Extinction, Adaptive Radiations, and Evolutions of Morphological Complexity

Question 1

What is continental drift?

Answer 1

movement of land masses over underlying hot mantle

Question 2

What did continental redistribution cause?

Answer 2

it caused changes in climate change which changed biodiversity

Question 3

What are the five major extinctions?

Answer 3

ordovician-silurian mass extinction, late devonian mass extinction, permian mass extinction, triassic-jurassic mass extinction, and cretaceous-tertiary mass extinction

Question 4

What happened during the Permian mass extinction?

Answer 4

nicknamed “the Great Dying”, 96% marine species, 70% terrestrial species lost, all life on earth derived from the remaining species that survived, causes were mainly unknown, asteriod impact, methane release, oxygen depletion, sea level changes, volcanism, or combination of all of them

Question 5

What happened during the Cretaceous-tertiary mass extinction?

Answer 5

death of dinosaurs as well as many other taxa, many taxonomic groups including dinosaurs had been in decline for several million years

Question 6

What is the evidence for asteroid impact as the cause of C-T extinction event?

Answer 6

layers of the element iridium in sedimentary rock correspond to time of the extinction event, no dinosaur found above the C-T boundary, crater is the size predicted by Dr. Luis and Walters Alvarez, and the collision would have released energy equivalent to loo trillion tons of TNT

Question 7

What is adaptive radiation?

Answer 7

evolution of diversely adapted species from a common ancestor upon introduction to new environmental opportunities

Question 8

What are the major genetic mechanisms controlling structural and morphological changes?

Answer 8

changes in rate and timing of gene expression, changes in spatial pattern, creation of new genes, and changes in gene regulation

Question 9

How does the rate and timing of gene expression affect an organism?

Answer 9

small changes in the relative rates of growth during development can have dramatic effects on the shape of the adult organism

Question 10

What is heterochrony?

Answer 10

evolutionary change in the rate or timing of developmental event

Question 11

What is paedomorphosis?

Answer 11

they keep childhood characteristics/features, ex. axolotl

Question 12

What do HOX (homeobox) genes determines?

Answer 12

they determine the development of body parts, affects morphology of an organism