'Badger's Patch' is the area of countryside on a radius of the author's home town. It includes the Stort Valley and its tributaries as well as several nature reserves and sites of natural history interest. The area is also covered by the Bishops Stortford Natural History Society- hence bsnhsdiary!
Thursday 19 March 2020
Frog Blog.
Frogs spawned on Sawbridgeworth Marsh on the 9th March.
Pictures by DS. Sound recording RR.
The eggs in the spawn are surrounded by mucus which helps to protect the eggs from predators and changes in temperature.
The egg is dividing many times to form an early embryo called a blastula. This becomes a hollow ball of cells which then gets pushed inwards to form a cup shape which is called a gastrula. At this stage the fate of the cells becomes determined into which ones will become muscle, nerve and organ tissues.
Areas can now be determined which will become the head, body and tail. Small gill buds are appearing on the side of the head.
The gill buds have formed into feathery gills. The whole body is still contained within the egg membrane.
The developing tadpoles have now got some degree of muscular movement and start to break free from the egg membranes. They tend to collect together at the top of the spawn mass.
