Theme 5 Flashcards
When did primates first arrive?
The early Palaeocene
What are the phenotypes of primates?
Nails (not claws), separated radius and ulna, upright posture.
What are the sensory adaptations of primates?
Reliance on vision, forward facing eyes, stereoscopic vision, eyes enclosed in socket, some colour vision. Less reliance on smell=reduced snout. Increased brain size means higher cognitive functions.
What are the dietary adaptations of primates?
Omnivorous diet, diphyodont (2 sets of teeth, baby and adult), heterodont (4 different types of teeth).
What are the dental formulas for primates and humans?
Primates: 2133 Humans: 2123
Arboreal Evolution Hypothesis
Monkeys live in trees and need hands to grasp
Visual Predation Evolution Hypothesis
Hunt prey easier
Angiosperm Radiation Evolution Hypothesis
Adapted due to rapid angiosperm evolution
Narrow Niche Evolution Hypothesis
Less pressure for monkeys to be on the ground
What is the intermembral index and what does it have to be for something to be quadrupedal?
Length of forelimbs/length of hindlimbs. Must be greater than 70.
What characteristics are in individuals with low intermembral index?
Vertical clinging and leaping, bipedalism
Folivores diet and foraging
Have high, sharp molar cusps; eat leaves
Frugivores diet and foraging
Low, rounded molar cusps; fruit stored in cheek pouches
Insectivores diet and foraging
Sharp, pointed cusps; eat insects
Gummivores diet and foraging
Eat gum, sap, resin
Graminivores diet and foraging
Eat grass
Strepsirhini characteristics
Small body size, nocturnal, tooth comb, grooming claw, well-developed sense of smell, elongated snout, rhinarium (wet nose)
Strepsirhini: Lemuriformes
Five families, 112 species, only on Madagascar. Varous ecological niches, wide range of behaviours and diets.
Strepsirhini: Lorisiformes
2 families, 11 species. Found in Africa and South East Asia. Solitary, quadrupedal.
Haplorhini characteristics
Larger body size, diurnal, tail, nails on all digits, no rhinarium, decreased smell reliance, increased vision reliance, complete closure of back orbits, trichromatic vision, large brain relative to body size.
Haplorhini: Tarsiers
5 species found in south east asia, nocturnal and solitary, grooming claw, vertical clinging and leaping, elongated tarsal bones, eat insects, can rotate head 180 degrees, eyes same size as brain.
Platyrrhini Characteristics
70+ species, tropical and subtropical forests, central and south america, broad flat nose, outward facing nostrils, diurnal and arboreal, prehensile tail, 2133 dental formula.
Catarrhini Characteristics
Old world monkeys, apes and humans. Tropical and subtropical forests and savannah, Africa and Asia, narrow noses and downward facing nostrils, ischial callosities, greater size range and sexual dimorphism, dental formula: 2123
Catarrhini: Cercopithecoids
Macaques, baboons, mandarins.
Catarrhini: Colobinae
Langurs, Colobus, and Probiscis monkeys, specialized stomachs, reduced thumbs.
Hominoidae
Largest, diurnal, no tails, nails on all digits, more complex behaviour, brain, and cognitive abilities. Increased period of infant development and dependency.
Hylobatidae
8 species, rainforests and South East Asia. Brachiation, reduced thumbs, frugivores, monogamous, little sexul dimorphism.
Orangutan
Found in Borneo and Sumatra, largest of Asian apes, arboreal, knuckle-walkers, solitary, sexual dimorphism, large cheek pads and laryngeal sacs, less than 30000 in the wild.
Gorilla
2 species, largest primate, Western and Central Africa. Terrestrial knuckle walkers, vegetation, silver backs.
Chimpanzees
Found in Africa, omnivores, males dominant over females.
Bonobos
Slightly built, Democratic Republic of Congo, females dominant over males, non-reproductive sex.
Northarctus
Estimated to be 50 million years old-defining features being human like hands (first time seen)
When did colour vision develop and why?
23 million years ago. Spot differences between food.
What is opsin?
Proteins that allow us to perceive colour. We started with 2 and developed a 3rd, created due to duplication in genes and mutations.
Where were the first bipedal fossils found?
Ethiopia (Lucy).
What are the consequences of bipedalism?
Back problems. Spine has weird curve to help us stand upright, but this is unnatural. Creates wedge fractures.
What do our brains share with primates?
Hand eye coordination and visual area
Differences in our brains
Baby monkeys understand object permanence, human babies don’t, which is largely due to longer childhood, which helps us learn more but slower. Our cortex contains more neurons (16 million)
Amphioxus
No brain, but have DNA that could have created a human brain.
