1. What sort of climatic and geological changes occurred during the Miocene and
ID: 292378 • Letter: 1
Question
1. What sort of climatic and geological changes occurred during the Miocene and how would these changes have affected the evolution of the first ape-like primates?
2. What do we know, or think we know, about the early evolution of euprimates? Where do we place them on the primate family tree? What are their defining characteristics?
3. In order to accurately interpret the fossil record, there are several steps, outlined in your chapter, that researchers must take when they discover a new fossil. Which of these steps do you think is most critical to the accurate interpretation and presentation of a fossil to the scientific community?
4. What do we know about the earliest possible hominin found to date, Sahelanthropus tchadensis (nicknamed Toumai)? How old is it, where was it discovered, which anatomical features place it in the hominin line, which features are ancestral vs. derived?
Explanation / Answer
ANSWER-
1.)During the miocene,geologically ,continents slightly changed their position resulting change in global circulation pattern .Overall mountain building processes accelerated and aridity was seen due to mountain building that paved the way for grasslands.Climate was warm with expansion of subtropical forests ,and a diversification of catarrhine primates in Africa and the Arabian peninsula.Non-cercopithecoid catarrhine primates were diverse in early and middle miocene of Africa. During this epoch of global warming and expanding of forests,the modern ape Hominoidea radiated and diversified in Africa and Eurasia.
2.)The early euprimates are traced from Eocene ,about 55 million years ago.They are allocated to two groups-lemur like adapiforms and the tarsier-like omomyiformes.
3.)The most critical step for any palaeontologits would be to find the index fossils and the rock facies ( usually sedimentary) they exist in.Index fossils are most reliable as they have short tie range but widespread geographical distribution.
4.)It is an extinct homininae species and is the ancestor to Orrorin and very close to duration of chimpanzee.
It was discovered 7 million years ago in Chad in Central Africa.
the reason for placing it in the hominin line are-small canine teeth,spinal cord opening underneath the skull .
ancestral features-chimpanzee sized brain,primitive teeth
derived features-flat face,dentition not like apes,massive brow ridge,foramen magnum oriented similar to bipedal creatures.
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