16. Maori mystery Flashcards
When did the Earth’s landmasses begin to have good resemblance to today?
Cretaceous, more similar in the Paleocene (North America and Europe fully formed)
What current continents was Gondwana composed of?
Mostly Southern ones
South America, Africa, Arabia, Madagascar, India, Australia, New Zealand and Antarctica
What is Nothofagus?
A genus of trees and shrubs closely related to Oak and Beech
Why are Nothofagus so easy to recognise in the fossil record?
They have quite large seeds and very distinctive pollen.
Where is Nothofagus found?
Australia, New Zealand, Papa New Guinea, Indonesia, a few other oceanic islands (e.g. in the pacific ocean)
What is vicariance?
When the geographical range of a biota is split into discontinuous parts by the formation of a physical or biotic barrier to gene flow/dispersal
What is allopatric speciation?
When two or more closely related species are separated by reproductive isolation (usually by vicariance)
State the two explanations for Nothofagus’ distribution.
- Vicariance explanation
- Dispersal explanation
How does vicariance explain the modern distribution of Nothofagus?
Using previous continent arrangements of Gondwana which would’ve put New Guinea, New Zealand, Australia and South America all very close.
What problem stops Vicariance from fully explaining the distribution of Nothofagus?
Nothofagus is found on some islands that were never connected to other land, e.g. islands in the Pacific Ocean
What are some ways plants can be dispersed island to island?
Seeds carried on wind, birds carrying seeds, vegetation rafts.
What recent discovery has been made about the continent New Zealand is on?
New evidence that New Zealand is part of a mostly submerged continent ‘Zealandia’
What is so interesting about the uniqueness of New Zealand’s biota?
New Zealand has very very distinct biota from that of other connected continents from Gondwana
What are the 3 categories of unique New Zealand species? (based on origin)
Relic, Novelty, Immigrant
What is a relic species?
A species from before the continents split that has died off/evolved on other continents recently
What is a novelty species?
A species that is new to Zealand and has evolved from a relic/immigrant species.
What is an immigrant species?
One that has moved to New Zealand and may have evolved/died elsewhere
What is the molecular clock model?
Studying mutation rates of biomolecules to work out when lifeforms diverge
Are most of New Zealand’s species immigrants, novelty, or relic species?
Most of them are new arrivals (immigrant)/ evolved from recent arrivals.
What is the ‘Oligocene drowning’?
A theory that New Zealand was almost entirely submerged during the Oligocene (34 - 23Ma)
How might the ‘Oligocene drowning’ theory account for why New Zealand’s species are mostly new arrivals?
New Zealand being submerged would’ve killed off most of its endemic species - leaving it depauperate and prime for niches to be filled once it emerged again.
Most of New Zealand’s species arrived in the last ____ million years.
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