becoming human-ch11 Flashcards
What are the taxonmic classifications of humans
Humans belong to the kingdom Animalia
Humans belong to the Phylum, Chordata
Humans belong to the class, Mammals
Humans belong to the order, primate
Superfamily-hominoidea
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5. Humans belong to the family, Hominidae
Humans belong to the tribe Hominini
Humans belong to the genus–homo
7.Humans belong to the species- sapiens
Hence the scineitifc name for humans is homosapeins.
Characteristics of primates
rimates have a prehensal abilty, meaning they have the abilty to grip objects–they can do this because of their opposable digit(big thumb or toe) which allows them to grasp objects with precision and power grip
Primates have a flexible spinewhich increases flexibilty, allowing primates to live in trees.
Primates have a large cranium
Primates have 3D colour vision, broad rib cage, superior intelleigene and problem sovling skills
Characteristics of mammals
Mammals are warm blooded verterbrates,
Mammals have fur/hair
Mammals have mammary glands to produce milk
Mammals have one lower jawbone directyl attached to the skull, giving mammals a powerful bite
, three middle earbones and variety of teeth include incisors. molars, premolars an d canines. Canines tear food apart whilst molars grind down food, incisors bite/pierce food
Characteristics of Hominoids
Hominoids have a shorter spine, no tail, longer arms than legs(except humans)
Characteristics of hominins
Hominins have the characteris of bipedalism which is unique to hominins such as homo sapiens and homo erectus.
Compare the humans which are hominis to gorillas
Humans have an S shaped spine, whereas gorillas have a C shaped spine.
Humans have shorter hands, straighter fingers and longer thumbs whereas gorillas have more curved fingers that are adapted for climbing trees and knuckle walking.
Gorillas have a funnel shaped ribcage, whereas Humans have a barrel shaped ribcage.
What are hominoids
Hominoids(super family) are a group of primates that includes all apes except monkeys that are characterised by larger brains, no tails, and more complex behaviours.
What are hominins
hominins are a group of primates where humans seperatefrom ther hominoidsthat includes modern humans and their closest extinct relatives, characterized by traits such as bipedalism and larger brain sizes
Compare hominoids and hominins
Hominoids are comprised of all apes but not monkeys. Homoinds charactierisics include no tail, broad chest, large brain, semi erect or fully erect posture. examplesinclude gorillas, chimpanzees
Hominins:
Where are where humans seperate from other hominoids, include modern humans, extinct homo ancestors, and the charactierisc sinclude bipedal iwht modified pelvis, feet central foramen magnum.
examples include humans or homo neanderthalensis.
What happened in evolution when the cranium capacity increased in size
when the cranium capacity increased in size, there was an increase in brain mass
Why do hominins or humans have an increased cogntiie abilty compared to earlier homo species
eg. whyare humans smarter than gorillas
Cerebrum became more folded, which increased surface area of the brain, resulting in more neurons and increased connection between brain cells. With this increased intellcutual bailty came the ability of speech, the feeling of complex emotions, higher order decision making, planning.
Leading to enhanced cognitive ability
Why can humans talk but not other homo specieslike gorillas
Cerebrum became more folded, which increased surface area of the brain, resulting in more neurons and increased connection between brain cells. With this increased intellcutual bailty came the ability of speech, the feeling of complex emotions, higher order decision making, planning.
What does the fossil record of skulls suggest about brain size in hominins
The fossil record suggests that brain size in hominins increased over time.
What change in the cerebrum is associated with increased cognitive abilities?
An increase in the number of folds in the cerebrum resulted in a larger surface area, which enhanced cognitive abilities due to more neurons and increased brain cells.
What were the changes to the skull of hominins due to evolution
a more centralised foramen magnum
A less protuding chin
Smaller teeth
lessening of the brow ridge
flattening of the face
Bipedalism
the abilty to walk on 2 legs and upright posture.
How did bipedalism change the spine of hominins/humans
hominins such as humans due to bipedalism have a S shaped surve to accomdate the upright walking posture and support weight, compared to the C shaped curve in gorillas.
hominins such as humans due to bipedalism have a S shaped surve to accomdate the upright walking posture and support weight, compared to the C shaped curve in gorillas.
Bipedalism results to changes in the pelvis to become more narrow,and made the position of the foramen magnum more central to support the upright stance
How did bipedalism cause changes to legs in hominins
legs are stronger than arms
stronger knee joint
Knee position inwards(carrying angle) to help with the weight of the body when walking
What changes to feet and hands did bipedalism cause for hominins
Bipedalism caused arched feet so that feet could move in a spring like motion
Toes are shorter
Bipedalism caused refine precision grip of hands.
What are the advantages of bipedalism
Advantages of bipedalism:
Hands are free to carry young, hunt
Assists in thermoregulation
Ability to see higher grounds
In hominins evoltuion how did limb structure chnage
Australopithecines have longer arms for movement on trees but overtime, arms shortened for homo genus because the arms were no longer used to climb on trees, instead to carry young, hunting, and preparing food.
Hominins developed longer legs to assist in walking upright because they were bipedal, this is also enery effienct becuause longer legs allowslonger strides saving energy
Australopithecus
australopithecus
ancient hominin ancestor from which Homo evolved 4 million years ago
Evidence shows that they walked upright, yet still climbed on trees
Evidence for examining homosapiesn past
fossil records to determine relatdness with other species like Naedethnrals
2.Molecular homology( DNA sequences or amino acid sequences)
3.New fossils are still bein discoverd
4.Many fossils have differnet interpretations of human fossil records
Various theories on the evolution of humans:
ultiregional hypothesis
Out of Africa Hypothesis
Out of Africa Hypothesis
suggests that Homo sapiens evolved in Africa around 200,000 to 300,000 years ago then emigrated 100,000 years later to Europe, Asia and austriala, replacing existing hominin species such as Homo erectus.
Most widely accepted hypothesis
Evidence of out of aFRICA hypothesis
Evidence:
-mtDNA analysis of modern humans trace back mitochondria lineages from a common ancestor in Africa
-Modern humans show little genetic diversity compared to other species suggesting we originated from a small centralised population
-Oldest Homo sapiens fossil found in East Africa dated 160,000 years compared to fossil in middle East 100,000 years old.
-Evidence of tools, cave paintings found in regions of Western Europe around 40,000 years old.
Multiregional hypothesis
Suggests evolution of modern humans from Homo erectus to Homo Sapiens was an ongoing process across all regions of the world with gene flow between different continental populations.
Homo erectus moved out of Africa to other parts of the world
Homo erectus evolved into Homo Sapiens in different regions
Limited evidence.
Not accepted.
When was the arrival of aboriignal australians
Arrival of Aboriginal Australians between 50,000 and 65,000 years ago.
Q: What does genomic research suggest about modern Aboriginal Australians’ ancestry?
: It suggests that they can be traced back to the ‘out of Africa’ model when the first humans spread throughout the world.
What is Sahul?
Sahul was a supercontinent that included present-day Australia, New Guinea, and Tasmania, which became geographically isolated due to rising sea levels.
What evidence exists of the impact of Aboriginal Australians’ migration
Evidence suggests the extinction of large Australian terrestrial animals 42,000 years ago due to the rapid migration of Aboriginal Australians.
Migration of aboringal asustrialains
The first migrants reached Sahul, a supercontinent that included Australia, New Guinea, and Tasmania. Rising sea levels later separated this landmass, leading to geographic isolation. This isolation impacted the region’s flora and fauna, contributing to the extinction of large Australian animals around 42,000 years ago
‘Country’:
refers to relationship between individuals and ancestral lands and seas
Proof that humans breed with Neanderthals
Evidence suggests crossbreeding between the two species
Neanderthals were our close evolutionary cousin
Both existed in Europe and Asia between 40,000 and 100,000 years ago
mtDNA from Neanderthal fossils suggest we were a separate species that shared a recent common ancestor around 400,000 years ago
Comparing Neanderthals and Humans
Neanderthals had:
Wider nose
Shorter limbs
Stockier build
Enlarged brow ridge
Larger cranial capacity
Better resistant to cold climates
Evidence to suggesting interbreeding between humans and Neanderthals
Evidence: Nuclear DNA studies show 1-4% of human genome is identical to Neanderthals. Only found in non-African populations and not in sub-Saharan African genomes. This suggests Neanderthals may have interbreed with humans as they left Africa and did not interbreed with African humans
Evidence: 100,000-year-old Neanderthal fossil in Siberia contained human DNA. This suggests that a population of Neanderthals in Siberia interbred with humans 100,000 years ago.
What are the new hominin species
Homo Denisova
Homo luzonensis
Australopithecus
ancient hominin ancestor from which Homo evolved 4 million years ago
Evidence shows that they walked upright, yet still climbed on trees
Australopithecus characteristics
a
smaller skull size
2.wider rib cage
longer arms, shorter legs, suggesting able to climb on trees
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Why is the human fossil record so hard to interpret?
Not all individuals die in conditions to allow fossilisation
Rock layers and the fossils they contain may erode and disappear over time
Many rock layers are inaccessible to palaeontologists, so not all fossils have been found
History of life key events
