1. Pancreas
2. Spleen
3. Kidney
4. Liver
Liver
1. Struggle for existence
2. Discontinuous variations
3. Parasites and predators as natural enemies
4. Survival of the fittest
Discontinuous variations
1. SA node
2. β-cells of Langerhans
3. dorsal root of spinal cord
4. epithelial cells of stomach
SA node
1. 50%
2. 25%
3. 100%
4. 75%
50\%
1. I131
2. U238
3. Ra224
4. C14
I131
1. Sponge
2. Earthworm
3. Cockroach
4. Hydra
Hydra
1. Seasonal isolation
2. Reproductive isolation
3. Behavioural isolation
4. Temporal isolation
Reproductive isolation
1. natural selection
2. induced mutation
3. reproductive isolation
4. genetic drift
natural selection
1. Wings of birds and locust
2. Wings of birds (sparrow) and pectoral fins of Fish
3. Wings of bat and butterfly
4. Legs of frog and cockroach
Wings of birds (sparrow) and pectoral fins of Fish
1. mutation
2. isolation
3. polyploidy
4. sexual reproduction
polyploidy