CHAPTER 10: HUMAN CHANGE OVER TIME Flashcards

Question

Homo Luzonensis

Answer 1

- teeth and finger bones, part of a foot and part of a femur were discovered in the Philippines (remains came from three diff people) - lived at least 50000-67000 years ago on an island - it is classified as Homo - activity of the species → cognitive ability to make stone tools and hunt w them

Answer 2

- discovered in 2003 on Indonesians island of Flores - 1.1m tall - small cranial capactiy - intelligent - used fire, made stone tools

Answer 3

- out of Africa states that homo sapiens evolved in Africa and then left, replacing other human groups - more evidence to support this hypothesis - **small scale migration:** one smaller move 120 000 years ago into the Middle East - **large scale migration:** a larger move 60 000-70 000 years ago into all other continents (Europe and Asia then all other continents) - H.sapiens evolved in Africa about **300,000** years ago from **H.heidlbergensis** - around 70,000 years ago H.sapiens migrated out of Africa and spread across the rest of the world replacing populations of other hominin species - according to this theory, all modern humans are descendants of an African population of Homo sapiens

Answer 4

- the multiregional hypothesis states that homo erectus left Africa and evolved into homo sapiens in different t locations - homo sapiens evolved in different parts of the world, in parallel, from populations of Homo erectus

Answer 5

- to trace human migration - assumptions are made - homo sapiens and Neanderthal evolved from homo heidelbergensis - homo heidelbergensis evolved from homo erectus/ergaster

Answer 6

- can be more useful than nuclear DNA because: - it is inherited via the maternal line and does not undergo recombination - *the only variation that exists is from **mutations accumulating over time*** - there is a **non-coding** region called the d-loop → has a higher rate of mutation than other regions - the particular mtDNA sequence of the D-loop of each person is called that person’s **haplotype** - the **various haplotypes** worldwide fall into a number of large clusters known as **haplogroups** - a haplogroup is a group of people with similar haplotypes who share a common ancestor - Mitochondrial analysis is more accurate due to a known mutation rate and maternal inheritance. Molecular clock.

Answer 7

* mutations accumulate over time * - mtDNA is more useful than nuclear DNA - major human haplogroups can be used to track modern human migration across the world - due to a lack of genetic recombination and a high level of mutation in the D-loop - each haplogroup represents significant differences in mtDNA - allow for human populations to be tracked out of Africa

Answer 8

- 58,000 years ago, a population of H.sapiens split off from the main population, travelling east through Asia and making it to AUSTRALIA - as they passed through Asia, they interbred with H.neanderthalensis and Denisovans - moved out of north-east Africa → the Middle East → Asia and then travelled south to Sahul→ From here different ancestors travelled both east and west - DNA evidence also suggests that modern hominins reached the Australian around **55,000 years ago** from South-East Asia, with distinct groups, from a **single initial migration,** spreading rapidly down the western and eastern coasts to occupy particular geographical areas. - the extinction of the Australian megafauna approximately **42,000 years ago** is also evidence for the rapid migration of modern hominins across the continent.

Answer 9

50 000 years ago

Answer 10

- mtDNA is conserved through the maternal lineage there is no recombination - the only thing that alters it is mutations overtime - we know the average mutation rate so we can determine the time of migration - African populations have a much higher genetic diversity likely due to them having more time to accumulate mutations. with this info we can find out approximately when new alleles were introduced occurred and approximately when humans migrated

Answer 11

* when: 100,000 - 120,000 years ago * where: Middle East

Answer 12

- due to the length of time they have lived in Australia - created strong + rich connections to their Country and Place - hundreds of different tribes (clans/mobs) that have unique languages and connections to their land across mainland Aus, Tasmania and Torres Strait ## Footnote prolonged connection over time of **specific populations in specific areas** of the Australian continent

Answer 13

- **evidence from mtDNA** - more diversity in mtDNA of modern African populations than the rest of the world’s populations combined - ***molecular genetic studies can be used to determine when lineages separated*** - migration of H.sapiens is an example of the **founder effect** - beneficial → high known mutation rate (bc it doesn't have repair mechanisms) → large diff between populations

Answer 14

- 99.7% of the nucleotide sequences of the modern human and Neanderthal genomes are identical - comparison of nuclear genomes of modern humans and Neanderthals → 1-4% of the DNA of ALL non-African modern humans came from Neanderthals - native Africans do not have any Neanderthal DNA

Answer 15

- it is difficult to determine patterns when natural variation exists as: - much of the evidence is only based on fossils and DNA and this evidence is largely incomplete - hard to definitively prove whether the extinct organisms were able to interbreed (and thus be classified as the same species) - may be many species in which no fossilisation occurred or fossils are yet to be found - conflicting dates using different tech -> esp is specimens are old/incomplete - falsifications of fossils - difference in intepretation

Answer 16

- mtDNA haplogroups are unique to Aboriginal and Torres Strait Islanders peoples diverged from other groups - the large variation in these haplogroups reflects the large time frame since Aboriginal and Torres Strait Islander peoples diverged from other groups - **large number of haplogroups in Indigenous Australian DNA**

Answer 17

- **evidence from fossils** - fossils of H.sapiens older than 70 000 years may have arisen because - H.sapiens left Africa a number of times since evolution 300 000 years ago but were unsuccessful until 70 000 years - fossils found in all regions of the world

Answer 18

**Hominin:** the group consisting of modern humans, extinct human species and all our immediate ancestors (including members of the genera Homo, Australopithecus, Paranthropus and Ardipithecus). **Hominoid:** the group consisting of all modern and extinct Great Apes (that is, modern humans, chimpanzees, gorillas and orang-utans plus all their immediate ancestors).

Answer 19

- humans are part of the taxonomic tribe Hominini - hominins have adaptations that **enable the wrists and hands to manipulate objects and use tools**. - skull differences **between hominoids and hominins** - compared with other apes, humans are capable of **advanced cognitive capacity, and complex language and belief systems.**

Answer 20

* there are many more copies of mtDNA in each cell * mtDNA has a known rate of mutation * mtDNA mutations accumulate or are not repaired * all changes in nucleotides are a result of mutations rather than recombination * mtDNA inherited from mother only allowing for a more direct line of relationships to be established. * less likely to degrade * used for determining **lineage.**

Answer 21

* more bases and therefore information available * DNA from both parents can determine if interbreeding occurred * presence of introns can reveal more **inherited mutations**

Answer 22

* mtDNA is inherited from mother only, whereas nuclear DNA is inherited from both parents * mtDNA has **fewer bases** compared to nuclear DNA * **no recombination** in mtDNA compared to nuclear DNA * mtDNA used for **lineage/migration** compared to nuclear DNA for **parentage/relationship** between species * mtDNA has a **faster mutation rate / less conserved** compared to nuclear DNA.