bio 108 topic 35: primates and humans

Primates what r they

• include lemurs, monkeys apes

• Humans part of apes evolved from mammalian ancestors that lived in trees

Shared derived traits of primates (4)

1. Grasping hands and feet

   • opposable thumbs

   • Precise grip

• Digits w flat nails and sensitive tactile pads for better control and touch sensitivity

2. Flexible limbs and shoulder joints

   • arboreal and terrestrial movement

   • Wide range motion bc shoulder joints and mobile hips

   • (Climb walk leap)

3. Forward facing eyes

   • binocular vision for accurate distance judging

   • Rely on vision than smell

4. Large brain relative to body

   • big in learning memory problem solving areas

   • Complex social behaviour

   • Extended parental care (babies dev skills via observation and practice)

Anthropoids include

Monkeys and apes

Apes diverged from

Old anthropoids

Apes have

• no tails

• Large brains

Great apes

• orangutangs

• Gorillas

• Chimpanzee

• Bonobos

• Humans

Human and chimpanzee genomes are 99% similar meaning

Tehy shared a common ancestor

Not humans evolved from chimpanzees

Shared derived traits of humans (4)

Obligate bipedalism

• only primates adapted for walking upright

Larger brains

• complex language, thought, artistic

Reduced jaw and face structure

• small teeth, not protruding jaw, flat face

Extended childhood and learning

• results in and advanced learning and brain dev

Challenges that pushed for bipedalism

• large mammal predators

• Comp from terrestrial primates

• Change in habitats (decline in arboreal env and more grasslands )

Pros of bipedalism

• enhanced visibility of predators and prey

• Energy efficient locomotion (good for long distance travl’

• Better thermoregulation in open habitats (Max breeze and min body sees hot sun during midday)

• Free hands to carry food tools and babies

Cons of bipedalism

• vulnerable to foot injury

• Strain in hips, back, knees and ankles

Hominin

Small brains

Increasing bipedalism Formerly called hominids

More closely related to humans than chimpanzees

Evolutionary history shows many branches coexist but only humans alive today

Australopiths

Paraphyletic assemblage of hominins living bw 4 and 2 million years ago

Evidence of tool usage

Two kinds of australopiths

Robust: sturdy skull powerful jaw

Gracile: slender and lighter jaw

Homo species

Fully bipedal and large brained

First we’re Homo ergaster and Homo erectus

What is reduced sexual dimorphism in Homo species

Increased pair bonding and reduced make-make competition

Who did Homo heidelbergenesis evolve from? And what’re they

Likely from Homo erectus that stayed in Africa

Large-animal hunter

• H. heidelbergensis was similar to H. sapiens in

Body proportions

Neanderthals and H. sapiens likely evolved from distinct

populations of

H. heidelbergensis

Neanderthal

• Thick boned

• cold adapted hominins

• Large brain

• Buried their dead

• Made hunting tools

• Lived in Europe 350 000 to 28 000 years ago

Humans

• in Africa 195 000 years ago

• Descend from Homo heidelbergensis

• Large brains

• Advanced tool use

• Increased behaviour complexness

• little genetic variation compared to other mammals