PRIMATE FAMILY TREE (TAXONOMY)
In your own words, define “grade” and “clade” or explain the differences between these two terms
Grade: A group of organisms with similar adaptations (but not necessarily close evolutionary relatives)
Clade: A group including an ancestor and all its descendants (i.e., Monophyletic).
There are NINE traits included in the “primate suite of characteristics.” Name 3 of these traits.
1. Grasping hands
2. Nails instead of claws
3. Postorbital bar
4. Forward facing eyes
5. Stereoscopic vision
6. Binocular vision
7. Large brains/High cognitive ability
8. Increased visual areas
9. Decreased olfactory areas
There are several historical figures that contributed greatly to the study of fossils and fossilization. Who is NOT one of these key figures?
Charles Lyell
There are 3 major hypotheses that explain primate evolution: arboreal, visual predation, and angio-sperm coevolution.
Generally define each and name which one is the ‘correct’ hypothesis that explains primate evolution.
Arboreal Hypothesis: Many of the features of primates evolved to improve locomotion in the trees (i.e., arboreality).
Visual Predation Hypothesis: evolved due to arboreal locomotion, specifically for detecting insect prey and guiding the hands/feet to catch insects
Angio-sperm coevolution: Primate traits evolved in response to the spread of flowering plants (angiosperms) and the opportunities they provided
This Eocene primate is considered one of the two groups included within the ‘euprimate’ classification. This group is considered the stem members of the strepsirrhine lineage.
Adapid
Thinking of the primate tree, what are the first two "splits” of the tree under ‘Primate’?
Haplorrhini—(monkeys, apes, tarsiers)
Strepsirrhini—(lemurs, lorises)
Define sexual dimorphism and explain why it occurs.
-Morphological (size and shape) differences between males and females of the same species
-Competition for access to females creates sexual selection
We spoke about the “geologic time scale,” put these categories of time in order from the largest time-scale category to the smallest time-scale category: Period, Epoch, Eon, Era
Eon --> Era --> Period --> Epoch
What (group) are considered the earliest ancestors to primates?
Name the fossil considered to be the earliest primate.
-Plesiadapiformes
-purgatorius
This Oligocene primate lived 33mya. It was considered a Medium-sized monkey (6 kg or 13.2 lbs), likely diurnal, arboreal quadruped. It was likely an early catarrhine, and may be ancestral to both Old World monkeys and hominoids
Aegyptopithecus
Name the species included in Strepsirrhines and TWO characteristics of strepsirrhines.
lemurs, lorises, galagos
Define ecological hypothesis and social hypothesis to explain why primates might have developed larger brains.
social hypothesis—allows individuals to navigate social groups
ecological hypothesis—large brains helps with complex foraging and hunting
Define the two terms: taphonomy and fossilization.
Taphonomy: the study of what happens to an organism after death
Fossilization: the preservation of an organism against natural decay processes
Euprimates are called the ‘first true primates.’ There are two groups included within the ‘euprimate’ classification.
*Hint: one of these groups is considered the likely ancestors to strepsirrhines and the other groups is considered the likely ancestors to haplorrhines.
Adapids and Omomyids
This early Miocene primate had no tail (ape-like) but monkey-like body proportions, arboreal quadruped, brain larger than monkeys but smaller than later apes. Represents stem ape before modern apes diversified
Proconsul
Haplorrhini includes all monkeys, apes, and tarsiers. Haplorrhini is divided into two sub-categories. Name the two sub-categories after Haplorrhini.
Anthropoidea + Tarsiers
Platyrrhini (New world monkeys)
Catarrhini (Old world monkeys and apes) --> Hominidae
In class, we covered six primate residence patterns. Name two of these residence patterns and one species of primate for each.
1. Polygynous—one male + multi-female; Owl monkeys
2. Polyandrous—multi-male + one-female; Marmosets and tamarins
3. Multi-male + multi-female; Chimpanzees
4. Monogamy—one male + one female; Gibbons
5. All male—(any) juvenile males
6. Solitary—Orangutans
Nicolas Steno created 4 Laws of Stratigraphy that are still used today. Which of these is NOT one of Steno’s Laws.
1. Law of superposition
2. Law of original horizontality
3. Law of lateral continuity
4. Law of vertical striations
4. Law of vertical striations
What time period did euprimates first appear?
1. Eocene
2. Oligocene
3. Miocene
4. Pliocene
1. Eocene
This middle Miocene ape was found in Europe 12.5-11mya. It had suspensory arms (long arms, flexible joints), thin enamel (likely ate soft fruits). Probably an ancestor of African great apes and humans. Shows clear ape-like locomotion and brain enlargement
Dryopithecus
Anthropoidea includes these two subgroups. Name the two subgroups and ONE species included within each subgroup.
Platyrrhini (New world monkeys); Marmosets, tamarins, aotidae (owl monkey)
Catarrhini (Old world monkeys and apes)--> Hominidae (any great ape, lesser ape, humans)
Primates are very social animals. They communicate to compete and to cooperate. Which of these statements is UNTRUE regarding primate communication + social structure?
1. They use different volume calls for different contexts (ex: Quiet vocalizations are used to mediate social encounters and/or placate; loud calls are for aggression or to transmit information across large distances)
2. They can understand kinship relationships and rank/social hierarchy
3. Males never help with offspring care; this is a female-only task
4. They can relate warning calls to the rest of the group, with the ability to communicate if they saw the danger or if they are just passing on the message from someone else who did.
3. Males never help with offspring care; this is a female-only task
FALSE
Explain the difference between relative and absolute dating methods. Name an example of each.
Relative: uses simple observational skills
Examples: order of stratigraphic layering (biostratigraphic layering), fluorine dating, cultural dating
Absolute: require the removal of small samples from artifacts, bones, soils, and rock and are considered destructive
Examples: radioactive decay, radiometric dating, Carbon-14, K-Ar/Ar-Ar, Uranium, Fission track dating
Miocene apes were starting to look and behave more and more like what was to become modern humans. However, they still lacked an important characteristic of later great apes and humans. Which of these primate traits was not yet existent at this period in time?
1. Larger brains compared to faces (i.e., we see larger brains, flatter/smaller faces)
2. Habitual bipedalism
3. Variable diets (dentition showing signs of smaller canines, larger molars)
2. Habitual bipedalism
This late Miocene ape was discovered in Pakistan and India nearly 12mya.
It had thick enamel, robust jaws → diet of hard foods, facial structure very similar to modern orangutans, arboreal but not fully suspensory.
Sivapithecus