Evolution Flashcards

Question

What is a Primate? -general traits that primates generally have some or all of

Answer 1

- Primates (including fossil) have SOME or ALL of these traits; - bony ring around eye socket or bony enclosed eye socket - hands or feet that are constructed so they can grasp objects (exhibit prehension) - opposable thumb - external genitalia; 2 pectoral mammary glands - nails on edges of digits (unguiculate) - binocular vision - long gestation - slow-post natal growth compared to maternal body size - emphasis on learned behaviour and social interactions - large brain size relative to body size

Answer 2

- early hominids appeard in Miocene (approx. 20 MYA) - 4 genera w/in - human group (Hominins) dates back to around 5 MYA - Features; - still larger brain - larger body size - mostly terrestrial - arms and pectoral girdle for suspension - highly reduced or absent tails - Y-5 shaped pattern on occlusal surface of molar teeth

Answer 3

- 'wise man' emerged approx. 200 000 years go - modern humans classed as Homo sapiens sapiens - various extinct subspecies such as Homo (sapiens) neanderthalensis, homo heidelbergensis

Answer 4

- upright posture and bipedal locomotion - larger brains - language capabilities and symbolic thought - the manufacture and use of complex tools - shortened jaw & shorter digestive tract (due to development of agriculture)

Answer 5

-Hominins: all species of genus Homo and their close relatives 3 features; 1. Bipedal 2. Flatter face with more pronounced chin 3. Brain size * first hominin fossil approx 6-7 MYA - central african fossil 7MYA (Sahelanthropus tchadensis) - Eastern African fossil 6 MYA (Orrorin tugenensis) - Eastern African Fossil 5.8-5.2 MYA (Ardipithecus kadabba) *Hominins split from the ape line of descent 5-6 MYA

Answer 6

- Group of hominins that evolved and diversified in Africa approx 3MYA - Various frames (some slight others robust) w/ massive jaws for feeding on plant material * walked upright - limb portions apelike - small brain - famous skeleton named Lucy (A. afarensis) *Australopithecus africanus (w/ large brain) is most likely ancestral candidate for early Homo

Answer 7

- Brain size is 600cm^3 or greater - evidence of tool use - jaw and teeth resemble humans - Early Homo representatives (Homo habilis & Homo erectus) - Later Homo representatives (Neandertals & Cro-Magnons)

Answer 8

-Lived 2.0-1.9MYA - large brain w/ enlargd speech area (derived from skull) - Omnivorous (hunters and gathers) - Primitive tools - May have had culture

Answer 9

-lived 1.9-0.3MYA - Larger brain than H. habilis - flat face with nose projected - tall and stood erect - striding gait - Advanced tools and fire (systemic hunters) - May have had language - may have migrated from Africa to Europe and Asia

Answer 10

- AKA out of Africa Hypothesis -> is most widely accepted hypothesis - proposes that modern humans evolved from archaic humans only in Africa - Then, modern humans migrated to Asian & Europe where they replaced the archaic species about 100000 years BP -waves of species that came out of Homo ergaster and differentiated into different species in different continents

Answer 11

- discovered in Germany 2000 years ago - Homo sapiens have 1-4% similarity to their DNA -> suggests interbreeding - massive brow ridges - nose, jaws, and teeth protrude forward - low and sloping forehead; no chin

Answer 12

- Lived about 40 000 - 10 000 years ago * oldest fossils designated to Homo sapiens - modern appearance - advanced culture including art, tools and maybe language - Good cooperative hunters

Answer 13

- Human variations b/w populations = ethnicities - Variations evolved as adaptation to local environments - i.e. skin colour and body shape - Bergmann''s rule: colder regions mean bulkier build - Allen's rule: colder regions mean shorter limbs, digits and ears

Answer 14

1. Positioning of centre of mass over lower limbs 2. Efficient maintenance of this position 3. Reduction of protrusions away from centre of mass (to be more efficient) Has only occurred 3 times in mammals; Kangaroo, Kangaroo mouse & humans

Answer 15

- gluteus maximum v. powerful hip extensor (prevents torso from falling over) - bowl shape, short and broad pelvis bone -> enables us to support abdominal organs - shorter ileum (decreases centre of gravity & makes childbirth easier as pelvis rotated) - spine has lots of ligaments attached - curvature of spine to distribute weight appropriately - elongation of neck of femur (import. in balance) - femur curves in to knee (centre of gravity) - Menisci present in knee to help weight distribution

Answer 16

- big toe adducted to facilitate walking - toes shorter so we don't trip - thickening of plantar fascia provides platform that can absorb energy and return it by giving added thrust - arches in foot = shock absorbers

Answer 17

- Prognathism: Projection of lower jaw and facial skeleton - Has been a decrease in the protrusion of the face (helps maintain the center of gravity - foramen magnum more inferior to cranium - pectoral girdle is wider laterally - Scapula more medial (apes have lateral scapula)

Answer 18

1. Spine exits inferior to center of skull and this = midline of body 2. Longer, S-shaped spine -> places trunk's center of gravity squarely over feet 3. Broader pelvis & hip joints keeps humans from swaying when walk 4. Longer neck of femur in humans cause femur to angle inward at knee 5. Human knee joint modified to support body's weight (femur larger at bottom, tibia larger on top) 6. Human toe not opposable - foot has arch that enables humans to walk & run long distances

Answer 19

``` Domain: Eukarya Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Family: Hominidae Genus: Homo Species: sapiens ```

Evolution Flashcards

(43 cards)