Industrial melanism in the peppered moth (Biston betularia) is a classic example of:
A. Gene flow
B. Genetic drift
C. Artificial selection
D. Natural selection
Answer: Option D
Solution (By JKSSB Mock Tests)
Industrial melanism is a classic example of natural selection in action. Before the industrial revolution, light-colored moths were more common as they blended with lichen-covered trees, avoiding predators. Pollution killed the lichen and darkened the trees, making dark-colored (melanic) moths better camouflaged. The population shifted to predominantly dark moths, demonstrating survival of the fittest.
Explanation:
Charles Darwin's theory of evolution, presented in 'On the Origin of Species' (1859), is based on two main concepts: branching descent (all organisms are related through common ancestry) and natural selection (survival of the fittest). Natural selection states that individuals with traits better suited to their environment are more likely to survive and reproduce, passing those traits to the next generation.
Explanation:
Cilia and flagella are motile structures with a 9+2 axoneme of microtubules. Their movement propels the cell or moves fluids. R explains the structural basis.
Explanation:
The juxtaglomerular apparatus (JGA) is a specialized structure where the distal convoluted tubule (DCT) comes into contact with the afferent arteriole. It consists of juxtaglomerular cells (modified smooth muscle cells in the afferent arteriole that secrete renin), macula densa cells (modified DCT cells that sense NaCl concentration), and extraglomerular mesangial cells. It plays a crucial role in regulating blood pressure and glomerular filtration rate via the renin-angiotensin-aldosterone system.
No comments yet. Be the first to start the discussion!