Impact of environment on speciation Flashcards
How were the Galapagos Islands formed?
By volcanoes
Why are tortoises’ shells a different shape and finches’ beaks
it’s representative of the food source available
What causes speciation?
populations separating and reproducing as they adapt to their new surroundings
What is allopratic speciation?
Speciation by geographic isolation
Allopatric separation is…
the same species on neighbouring islands with different climatic conditions
Peipatric separation is…
small population isolated at the edge of a larger population
Parapatric separation is…
same species moves to different climate zone on same island
Sympatric separation is…
block to gene flow within the same population
What causes darker skin in humans?
Exposure to UV light in higher tropics
Where were the first humans from?
Africa - lighter skin is therefore an adaptation
What vitamin is produced when we’re exposed to sun light?
Vitamin D (SHE WANTS THE D)
Why are there differences in human skin colour?
It needs to be protective whilst also allowing enough vitamin D in to be absorbed
What body shape is found further away from the tropics?
Rounder and squatter in order to conserve heat with less surface area
Where is child birth easier and why?
Away from the tropics as hips become broader
Why was fruit a large part of our ancestors’ diet?
As a source of vitamin C
Which creature lost body hair on the savannah?
Humans
Why did humans move onto the savannah?
As a result of climate change
What can new born babies do?
Swim under water and keep their eyes open
Where did humans move to and from?
The rainforest - water’s edge - water - the savannah
How do we know humans spent time in water?
Hair pores
Where are our aquatic origins?
East African coast - as we sought new types of food
With less hunting time our diet became…
higher in protein as we found crustaceans which had no predators thus no protection
What caused us to go upright
water - prevented us drowning
Why did we develop a taste for fish?
Forest became flooded, drought drove us to the sea
