Human Evolution - Ch 55 - Primate Origins and Evolution

Question 1

Start of the Triassic Period (252-201 mya), a group of vertebrates called therapsids had derived features such as upright posture and skeletal changes that suggest a muscular diaphragm to increase breathing, and a soft tissue secondary plate to allow for breathing while eating, all resulting in an increase in…

Answer 1

metabolic rate

Question 2

the first mammals were ___ (size), and ate ____.

• Females nursed offspring with nutritional ___
• muscular ____ lead to better respiration
• hair/fur for ____
• high metabolic rate
• complex cheek teeth allowed for efficient ___ ____
• bony palate separating food from airflow allowed for eating and _____ at same time

Answer 2

the first mammals were small, and ate meat.

• Females nursed offspring with nutritional milk
• muscular diaphragm lead to better respiration
• hair/fur for insulation
• high metabolic rate
• complex cheek teeth allowed for efficient food processing
• bony palate separating food from airflow allowed for eating and breathing at same time

Question 3

What are the 3 major lineages of mammals?

Answer 3

• Monotremeta (lay eggs)
• Marsupiala (pouches)
• Placentalia: true placental, make up most of mammals worldwide

Question 4

Our taxon, the Primates, consists of what three general lineages?

Answer 4

prosimians, platyrrhines (New World Monkeys), and catarrhines (Old World Monkeys + Apes)

Question 5

After what date was the origin of primates?

Answer 5

After K-Pg, so after 66 mya.

Question 6

Most primates live in what ecosystem? What are five characteristics of primates?

Answer 6

Forests.

1. highly visual (eyes forward, depth perception)
2. specialized limbs (ex. opposable toe/finger)
3. omnivorous dentition
4. two mammory glands, and give birth to 1 or a few offspring at a time
5. large brains

Question 7

Oldest primate fossil was found when, and what is the species related to it?

Answer 7

Oldest primate fossil is 65 mya (soon after K-Pg), but possibly 10 Mya earlier (molecular evidence)
-Plesiadapiforms

Question 8

Did we evolve from plesiadapiforms?

Answer 8

no, but they are the earliest relatives to primates

Question 9

In the Eocene (~56 mya), what two primate groups came up?

Answer 9

adapids (lemur-like), and omomyids (tarsier-like)

Question 10

Are humans apes?

Answer 10

yes

Question 11

Are humans catarrhines?

Answer 11

yes

Question 12

Catarrhines include what two general groups?

Answer 12

Old World Monkeys and Apes (greater + lesser)

Question 13

What is a postorbital bar?

Answer 13

where bones of forehead and cheek connect and form a bridge behind eyes

Question 14

Aegyptopithecus Zeuxis was one of the best-known species from Fayum (an early primate) – and it had a low sagittal crest. What is a sagittal crest?

Answer 14

A ridge of bone that allowed for greater surface area for attaching muscles which could produce great chewing forces

Question 15

The origin of New World Monkeys (platyrrhines): how did they get to South America?

Answer 15

most likely, some soil+vegetation+tree root rafts brought some Eocene monkeys from Africa to South America across the Atlantic

Question 16

Did platyrrhines (New World Monkeys) experience an adaptive radiation?

Answer 16

yes, in South America

Question 17

Platyrrhines vs. Catarrhines

Answer 17

• Platyrrhines have tails that can grasp surfaces, and better smell
• Catarrhines have shorter or no tails, and have better vision

Question 18

In the Oligocene (34-22 mya), what happened to catarrhines?

Answer 18

they diverged into apes (which includes us) and Old World Monkeys

Question 19

In the Miocene (~23 mya), what was the best-known ape, and what did it eat?

Answer 19

Proconsul, it mainly ate fruit

Question 20

Mid-Miocene, which primate taxon experienced an adaptive radiation?

Answer 20

Apes!