Unit 4 AoS2 HOMININ EVOLUTION AND INTERVENTION Flashcards
Definition of hominins
Hominins refers to existing as well as extinct bipedal (erect) primates.
*Collective term for all human species and their erect (bipedal) close relatives.
Definition of hominids
Smaller subgroup of the hominoids consisting of all of the great apes (ie orangutans, gorillas, chimpanzees) and humans but not gibbons.
What is a primate?
A relatively advanced order of mammals.
What are some of the features that all primates have in common?
- Relatively large brain for body size
- Hands typically have five long digits with opposable thumb (on hand and/or feet)
- Typically flat nails on end of digits
- Typically large forward- facing eyes (stereoscopic vision)
- Typically four upper and four lower incisors
- Flexible arm and shoulder sockets (stemming from life in trees)
- Tendency for erectness in stance
- Snout is reduced
- Reduced sense of smell
- Relatively long gestation period
- Parenting shown
- Possess hair/fur and mammary glands
What are some features associated with bipedalism?
- S-shaped spine
- Compact pelvis
- Change in angle of femur to tibia
- Pelvic girdle more bowl shaped than in apes
- Knee joint
- Flat (arched) foot but prominent heel bone
- Foramen magnum position is more central and at base of the skull
- Large cerebral cortex (forebrain)
- Large cranial capacity
- Reduced jaw size relative to skull
- Reduced canine and incisors (fewer, smaller teeth)
- Nose and chin more prominent
- Reduced brow ridge
- Reduced body hair
- Complex thinking and behaviour
What are the advantages of bipedalism?
- Ability to see over the level of forest grass and other vegetation
- Frees up hands to carry food
- Carry offspring while attending to other tasks
- Helped in using tools and subsequent hunting
- Thermoregulation:less surface area presented to sun and cold; greater airflow across body when lifted off the ground
- Efficient locomotion: low speed and longer distances
What is the most recent ancestor of Homo sapiens?
Homo heidelbergensis
What are ways in which the skulls from the ancestral Ardipithecus varieties to those of Homo species have evolved?
- Larger and more rounded skull
- More vertical forehead
- Reduced brow ridge
- More parabolic jaw shape
- Less protruding jaw
- Chin
- Reduced size teeth with uniformity in size
- No diastema
- Foramen magnum underneath skull (at base)
Why are primate fossils rare?
Primates have rarely lived in environments suitable for fossilisation since the habitats of most primates have been tropical or sub tropical rain forests; environments in which rapid decay of dead organisms is typical.
What are the features of the fossil Ardipithecus?
- 8-4.4mya
* upright stance,
* small skull,
* jaw similar to human
* heavy brow ridge
* large molars
Features of the fossil Australopithecus?
4-1.2mya
- upright stance
- small skull
- jaw similar to human
- heavy brow ridge
- large molars
- approx 1.5m in height
Features of fossil Homo habilis?
- 5-1.6mya
* evidence of tool use
* larger brains
* smaller teeth
* face less protruding
* very similar to humans
* brain size was approximately 500-800ml
Features of fossil Rudolfensis?
- Along with Homo habilis, H. Rudolfensis also lived in Africa approximately 2 million years ago
- Competitor of Homo habilis but was unsuccessful and became extinct
Features of fossil Homo ergaster/erectus?
- 8million-500,000 years ago
* More modern than Homo habilis
* Brain size of 900ml
Homo heidelbergensis fossil features?
~400,000 to 40,000 years ago in Africa, Europe and China
*Brain size 1,100-1,200ml
Feature of fossil Homo neanderthalensis?
15,000-25,000 years ago
- Used tools
- Keen hunter
- Occupied European and Near East regions
- Brain size 1400ml
Features of fossil Homo floresiensis?
The hobbit lived on the Indonesian Island of Flores only 94,000-13,000 years ago
What are the evidences needed in support of the Out of Africa hypothesis for the origin of modern humans?
- Modern humans should appear first in Africa and only later in other parts of the world
- Transitional forms from ancestral to modern humans should only be found in Africa
- Variation in mtDNA should be greater in African populations than other populations
Evidences required in support of multiregional hypothesis?
- Modern humans should appear throughout Africa, Asia and Europe during the same period
- Transitional forms should be found in Africa, Europe and Asia
- Variation in mtDNA should be approximately the same in human populations from all regions of the Old World.
What is cultural evolution?
*The evolution of all new characteristics, ideas, skills and customs that are not transmitted via genes but through communication, learning and symbolised behaviour.
Culture is the sum total of behaviour patterns of a social group, passed on by learning and symbolic behaviour, eg language, art, music, poetry and is not transmitted via genes but through communication.
Examples of cultural evolution?
- Moral values
- Foods eaten
- Technical skills
- Ideas and concepts (religion, science theories)
- Clothing and housing
- Language
- Art/music etc
What is technological evolution?
Technological evolution refers to changes in technology (ie application of science by humans) which gives humans increased control over their environment.
Eg. tools, machines, robots, medical procedures.
Examples of technological evolution?
- development of stone tools by prehistoric humans
- development of the printing press
- radio and television, iPods etc
Definition of hominoids
•Hominoid: broad group of primates, consisting of great apes, humans and gibbons
What does the Out of Africa hypothesis state and what are the evidences in support of it?
Homo sapiens evolved in Africa 100,000 years ago, then migrated out to other countries.
Evidence:
-Molecular evidence eg mtDNA, chromosome data show greater variation in African populations vs other population since there is more time available for mutations to accumulate in DNA of African individuals
-Transitional fossils for human evolution found in Africa
What does the parallel evolution hypothesis state and what evidences are available for it?
•States that: Homo erectus moved out from Africa to other continents. Homo sapiens species evolved parallel to each other on different continents
Evidence: presence of transitional fossils in many other areas eg H. florensiensis in Java, H. erectus skulls in China
What is biological evolution and what are the features associated with it?
•Changes in the gene pool of a population that have resulted from natural selection acting over generations.
Features:
•Very slow
•Traits transmitted only via parents
•Transmission can occur only from one generation to the next
•Acquired traits cannot be transmitted
•No choice which genetic traits will be inherited
•Transmission by genetic material (DNA)
•Not planned
What is selective breeding?
The deliberate selection by a breeder of specific animals or plants to provide the genetic material for the gene pool of the next generations. (ie which animals will breed)
What are some features that are selected for in beef cattle, dairy cattle and merino rams?
Beef cattle: -Bulls chosen for desirable market characteristics e.g meat yield and non-fatty carcass Dairy cattle: -milk yield -butterfat content Merino rams: -reduced fibre diameter (finer wool) -increase in length+strength of wool staple -increased yield