11. Human Changes Over Time Flashcards
List the characteristics that make a mammal.
A variety of teeth
One single lower jawbone attached directly to the skull
Three bones in their middle ear
Various amounts of hair or fur on their bodies throughout their lifetime
Mammary glands that produce milk
List the characteristics that all primates share.
Prehensile or grasping hand
Opposable thumb(s)
Flat finger nails instead of claws and sensitive tips of digits
Large, forward facing eyes.
Large brain volume in comparison to body size
List the characteristics that hominoids share.
No tails
Semi-erect moving posture (knuckle walkers)
List the characteristics of hominins.
Bipedalism Loss of opposable big toe/thumb Precision grip Increased brain case size Increased brain to body ratio Parabolic jaw and uniform teeth Longer gestation and care of young
State the morphological changes in hominins related to bipedalism
Humans have shorter arms in comparison to leg length than other primates and hominoids.
Our pelvis has become more bowl like than our ancestors
Human femurs have angled inwards to offer more support when walking.
Loss of opposable thumb on foot (toes all in a line)
S shaped of the spine
Describe the location of the foramen magnum in Homo sapiens.
The foramen magnum is more centralised on the base of the skull in Homo sapiens this means that the head is better balanced allowing for bipedalism
State the advantages of bipedalism
It saved energy so enabled them to walk greater distances and migrate
Allowed hands to remain free for carrying and manipulating objects such as tools.
Enabled greater vision to scan for predators.
List the evidence that supports the interbreeding between Homo neanderthalensis and Homo sapiens
Existed at the same time.
1–4% of the human genome (non-African populations) is identical to DNA found in Neanderthals.
State the evidence that supports Homo denisova as a new species
Nuclear DNA from the bone was found to be very closely related to Neanderthals, but different enough to be a new distinct species, termed Homo denisova, or Denisovans.
What is the evidence that supports interbreeding between Denisovans and Homo sapiens
Melanesian Homo sapiens share 4–6% of their DNA with Denisovans, but that other human populations do not.
State the evidence that supports Homo luzonensis as a new species
The fragments of fossils showed a new combination of features that were different from the combination of features found in other species in the genus Homo. Therefore, the specimens were believed to warrant their classification as belonging to a new species which was named Homo luzonensis.
State one peice of evidence that suggests Homo sapiens evolved in Africa
there is the greatest genetic variation in Africa mt.DNA (as mutations accumulate over time)
