Last class
• How do you determine relationships
amongst organisms?
• What are homologous and analogous
structures?
• Which are more useful for
determining relationships? Why?
1
Tuesday, March 15, 2011
Similarity between organisms
• What are the different forces that can create
similarities between organisms?
• Why do some similarities indicate relationship
while others do not?
• Which indicate a shared evolutionary past?
2
Tuesday, March 15, 2011
More...
• What are primitive and derived characteristics?
• Why are shared-derived characteristics most
useful in determining relationships?
• What is the principle of parsimony and how does
this apply to determining the relationships
amongst organisms?
3
Tuesday, March 15, 2011
Humans
• How are humans classified?
• Why are we classified in this way?
4
Tuesday, March 15, 2011
Mammals
• What characteristics define
mammals?
• What are these characteristics an
adaptation for?
5
Tuesday, March 15, 2011
We share traits with the Primates
6
Tuesday, March 15, 2011
We share traits with the
Primates
•
Primates share a set of traits due to a shared
early adaptation
•
Arboreal Adaptation - adapted to living in the
trees
•
Due to a shared ancestry
7
Tuesday, March 15, 2011
Traits of Primates
• Emphasis on vision
• binocular or
stereoscopic vision
• forward facing eyes
• postorbital bar or
post orbital closure
8
Tuesday, March 15, 2011
Visual Traits
Post orbital bar
Forward-facing
Eyes
9
Tuesday, March 15, 2011
Humans?
10
Tuesday, March 15, 2011
Limbs and locomotion
• Erect posture
• Generalized Skeleton
• Retention of clavicle
• Grasping hands with
opposability
• Nails instead of claws
11
Tuesday, March 15, 2011
Skeletons
12
Tuesday, March 15, 2011
Primate Hands
13
Tuesday, March 15, 2011
Humans?
14
Tuesday, March 15, 2011
Diet
• Generalized dentition
• Tendency towards omnivory
15
Tuesday, March 15, 2011
Primate teeth
16
Tuesday, March 15, 2011
Senses, brain and behavior
• emphasis on vision
• decreased snout and olfactory areas
• larger and more complex brain
17
Tuesday, March 15, 2011
Senses, brain and behavior
• longer gestation,
infancy, life span
• more k-selected
(tend towards
single offspring)
• greater
dependency on
learned behavior
• more social
18
Tuesday, March 15, 2011
Primate trends
19
Tuesday, March 15, 2011
• Arboreal adaptations
• Dietary plasticity
• Behavioral complexity
20
Tuesday, March 15, 2011