Pleistocene ice ages and mammal mega fauna extinction

Question 1

when was the last glacial maximun

Answer 1

started 25 kyr ago and ended 11 kyr ago

Question 2

glacial and interglacial periods effects on plant biomes

Answer 2

Tundras, boreal-spruce forests, and pinewood hard forests were found further down south in North America compared to today
- follows the glacial movement

Question 3

mastodon teeth vs mammoth teeth

Answer 3

mammoth teeth are more washboard like and similar to modern elephants
mastodon teeth are more tooth like and diverged a long time ago from mammoths

Question 4

ice age carnivores of north america

Answer 4

American lion & cheetah, sabertooth cat, dire wolf, short-faced bears

Question 5

Quaternary (end-Pleistocene) MegaFauna Extinction:

Answer 5

only land mammals
“Megafauna”: mammals weighing ≥44 kg (~100 lbs)
Affected all continents but at different times
Dated at about 11 kyr B.P. (end-Pleistocene) in North America
Clovis culture (excellent spear points) in North America dated at ~13 kyr

Question 6

evidence against overkill hypothesis

Answer 6

Against: Megafauna in Australia went extinct long before humans arrived
Against: Bison were hunted too, so why are they still around today?
Against: extinctions happened in north america before Bering Land bridge

Question 7

evidence for the overkill hypothesis

Answer 7

For: timing of extinctions occurred relative to the arrival of humans in North America
For: evidence of megafauna being hunted
For: megafauna tend to take longer to raise children, thus making it easier for them to go extinct

Question 8

why might large body sizes make animals more susceptible to going extinct

Answer 8

Greater individual longevity
Longer pregnancies
Longer time to reach sexual maturity
Birth fewer offspring
Not as many individual megafauna to keep up with hunting humans