Topic 34: humans Flashcards
_____ is the only extant species of genus homo
Homo sapiens
Are Humans great apes?
yes
closest living relatives to humans
chimpanzee and bonobo
Clade Hominins includes
chimpanzees and bonobos, and humans and their extinct relatives
Humans differ from other extant great apes (Hominids) in
- Upright posture and bipedal locomotion.
- Larger brains
- Reduced jawbone and jaw muscles.
- Shorter digestive tract
Trends in hominin evolution
- Bipedalism (early). − Expansion of the brain (cranial capacity) and increased brain complexity (later). − Modification of the pelvis. − Reduction of teeth, face, and jaws. − Extended period of infant and child dependency - Increasing hairlessness. − Increased reliance on meat. − The emergence of tool use
challenges that favored natural selection for bipedalism
- Large mammals predators.
− Competition from terrestrial primates.
− Decline in arboreal habitats, and expansion of open grasslands
Advantages of bipedalism
− Increased ability to see predators and prey.
− Energy-efficient locomotion, especially for long-distance travel.
− Better thermoregulation in open habitats
- Frees hands for carrying food and infants, and for tool use
restructuring of anatomy for bipedalism
spinal curved like S, pelvis, legs longer, and skull attachment, foot (larger heel and larger big toe)
foramen magnum
repositioned so that the human skull balances directly on top of the vertebral column
Australopiths
paraphyletic assemblage of hominins living between 4–1.5 mya, fully bipedal, short and had sexual dimorphism, some tool use
Homo habilis
Simple stone tools, 2.4–1.6 mya
Homo ergaster
first fully bipedal and large-brained hominin (lived between 1.9–1.5 mya), first to live in hunter-gatherer society
the first hominin to leave Africa
Homo erectus
Homo heidelbergensis
Homo erectus in Africa gave rise to Homo heidelbergensis, similar to humans in body, sophisticated tool use,
Neanderthals and Homo sapiens both evolved from
Homo heidelbergensis
Neanderthals
Lived in Europe and Near East, Were cold-adapted hominins with stout physiques
Denisovans
- were a genetically distinct group of Homo that lived in Eurasia about 50 kya
- Denisovans interbred with Neanderthals and ancestors of some modern humans
Homo sapiens
large brains, a broader set of tools and hunting techniques, first to have artistic thought
Human migration out of Africa happened
200 kya
What proof do we have that humans arose in Africa
mitochondrial DNA (mtDNA)
