What is Speciation? | A Level Biology Revision

Speciation is pretty much the evolution of new species from existing species. A species being a group of organisms with similar genes which are able to interbreed to produce fertile offspring. If populations become seperated (geographical isolation) then they are no longer able to interbreed. This might be for a number of reasons  - lets take a huge mountain for example. Selection pressures will be different in both locations, for example ease of getting food or temperature may differ. Within these slightly different environments some are better able to compete than others - this  causes the allele frequencies to change in each population. The genes then, over time become so different they now can't interbreed.

Other keywords:

Stabilizing selection - this is selection which tends to favor the average (gets rid of the extremes)
Directional selection - this favors one extreme

This is specifically for AQA A Level Biology Unit 4

FIGHT!!!! | #PictureoftheMonth

For this month I thought I'd bring you a completely different picture, this time of two very territorial birds!

http://www.nhm.ac.uk/visit/wpy/gallery/2013/images/behaviour-birds/4742/light-path.html

The Emperor of ALL Penguins :)

Emperor Penguins are the heaviest and tallest of all the species of penguins - so heavy that they can weigh up to 45 kg. In fact, they're very cleverly adapted for life in the frozen climates of the Antarctic as temperatures can plumet to as low as -60C. They, like other Penguins huddle together to conserve their warmth and protect them from the wind. What's even more amazing is, is that they rotate so the penguin(s) on the outside don't get too cold! Despite the cold weather, they even continue to breed. During their breeding 'season' they lay a single egg and leave it behind whilst they go on hunting trips which can last up to 2 months! This isn't necessarily because they're neglectful but because sometimes, they might have to travel up to 50 miles purely to reach open waters where they feed on fish, squid and krill. The very important job of keeping the eggs warm, actually falls to the male penguins and once the females return, they have a belly full of food which they then regurgitate for the newly hatched chicks. Once their chicks are nicely fed, the female takes over and keeps the chicks warm in their brood pouches. This of course, frees up the male to take over foraging duties. The males then continue to hunt for food until the chicks have developed enough to cope with the Antarctic chill.

Puffins!

Since we went up to Northumberland this year, Puffins are my new favorite bird! We actually went on a boat trip to The Farne Islands and saw seals and puffins around the island, the highlight of my year!! :) In fact, during the height of the breeding season, there's around 37,000 breeding pairs of puffins and around 7,000 seals! 

My best close-up of the puffin!

Unfortunately, as we went slightly after the breeding season, we really only saw puffins on the water but it was a sight I wouldn't have missed for ANYTHING! :) It was just so incredible to see the puffins scampering away from the boat with beak-fulls of sandeel!  
It really doesn't surprise me that when they do breed however, their presence draws tourists from all over the UK to witness these amazing sights. 

Sunbathing seal!

The Farne Islands are home to just one of the three species of Puffins, the Atlantic Puffin. Much to many people's surprise, the male puffin builds the nest, partly to demonstrate partly strength and fidelity to nearby birds. In actual fact, the puffins put an incredible amount of work into building their nest, even lining it with grass, feathers and leaves to make it that one bit warmer! 

Seals!

Once the nest is built, their breeding season can begin. Unlike many other species they form long term relationships (scientists call these pair bonds) so over the years they can continue breeding together. Once the eggs have hatched and their chicks (called pufflings) emerge they rear their pufflings until they're strong enough to leave with their parents under the cover of darkness where they continue to grow and develop at sea, far from the coastline. However they may be back to their breeding spot soon as puffins have been recorded by scientists to breed as early as 3!

Where else can you see them then? Well as they spend most of the breeding season at very specific locations you need to pick and choose, although you'd stand a good chance of seeing them in Iceland as its home to around 10 million Atlantic Puffins with some specific colonies of them being well over a million.

My absolute favourite picture from the trip! 

They're actually incredibly skilled when it comes to feeding, you may have seen the classic shot of a puffin with its beak stuffed full of fish- sometimes well over a dozen. They can feed on all kinds of fish, from Sandeel and herring to capelin. As well as fish, they also feast on zooplankton. They actually have an amazing hinging mechanism in their beak which allows them to crosswire the fish so take longer foraging trips so they can come back to their pufflings with more energy and their young can thrive too.

Above all else I'd definitely recommend a visit to The Farne Islands, it's one of England's hidden gems!