Chapter 17 - Primate Evolution

Question 1

Who was Carlos Linnaeus?

Answer 1

• Carlos Linnaeus (1707 -78)
• one of the first scientists to consider that similarities between plants, animals and humans may have evolved from common ancestors.
• established the basis for the binomial system of naming organisms.

Question 2

What is the binomial system?

Answer 2

The binomial system uses the generic (genus) and specific (species) names for the scientific name of a species.
- using this system, humans are referred to as Homo sapiens.

Question 3

What are Primates?

Answer 3

Humans, apes, monkeys and other related animals all classified under the order of primates.

Question 4

What are the four main types of sources that provide evidence for evolution?

Answer 4

• Comparative anatomy or primates
• Comparatuve biochemistry
• Behaviour of living primates
• Fossils of primates.

Question 5

What are the first four divisions of the hierarchy?

Answer 5

1. Kingdoms - plants and animals
2. Phyla (singular phylum)
3. Classes
4. Orders.

Question 6

Describe the classification of humans with the primate order.

Answer 6

Order : Primates 
Suborder : Haplorrhini
Infraorder : simiiformes 
Paravorder : Catarrhini 
Super family : hominoidea
Family : homindae 
Subfamily : hominnae
Tribe : hominini
Genus : homo 
Species : sapiens

Question 7

What does arboreal mean?

Answer 7

Arboreal means living in trees or tree-like environment.

Question 8

Describe the three main trends of human digits

Answer 8

Mobility - Increasingmobility and ability to move digits independently of one another.

Petadactyl - with friction ridges

Opposability - First digit opposable and increasing length results in increased effectiveness of opposability.

Claws/nails - Primitive primates retain claws on some digits : higher primates have nails on all digits.

Question 9

Define prehensile

Answer 9

Being capable of grasping.

Question 10

Describe three main evolutionary trends of vision in primates.

Answer 10

Eyes - gradually became more forward facing to give stereoscopic vision. 120% of vision overlaps
Increased efficiency in vision.
Humans have rods and cones .

Eye sockets - eyes gradually became enclosed in a protective bony socket.

Visual area of brain - increased while the olfactory area of the brain decreased.

Question 11

What are rods and cones?

Answer 11

Rods are important for vision in dim light.

Cones are important for fine visual and colour distinction

Found in the retina of human eyes

Question 12

Describe 3 main evolutionary trends of the dentition of primates.

Answer 12

Amount of teeth - lemurs, lorises and new world monkeys have 36 teeth, old world monkeys, apes and humans have 32.
Two sets of teeth ; deciduous and permanent

Dental formula - of humans it is 2:1:2:3 (two incisors, one canine, two premolars and three molars on each side of the jaw.)

Monkeys have 4 cusps in their teeth, humans have 5

Question 13

Describe two main evolutionary trends of the olfactory system in primates.

Answer 13

Bone protection - nose and snout areas have generally become smaller and flatter.

Increase in vision as decrease in smell.

Question 14

Describe three main evolutionary trends of the brain in primates.

Answer 14

Size - increasing size of brain relative to size of body

Cerebral cortex - makes up an increasingly large proportion of the brain.

Convolutions - makes up an increasingly large proportion of the brain.

Question 15

How has the cerebral cortex in primates evolvedover the years?

Answer 15

• more accurate visual and tactile perception,.
• better coordination
• increases ability to locate food and develop special skills
• tool making
• greater variety of behavioural responses to meet a wide array of environmental problems.

Question 16

Describe four evolutionary trends of the gestation in primates.

Answer 16

• Rhythmical sexual cycle
• one offspring at a time
• sexual maturity is attained much later in apes and humans than lemurs.
• Long period of parental care.