Exercises

1. Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.

• In a large population of bacteria, there is always built-in variation. Some bacteria may possess a pre-existing mutation that makes them resistant to a particular antibiotic.
• When that antibiotic is used, the non-resistant (sensitive) bacteria die, while the resistant ones survive.
• The survivors multiply rapidly and soon become the dominant part of the population.
• This is an example of natural selection, where the environment (presence of antibiotic) selects for the 'fittest' individuals (resistant bacteria).

2. Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution. (Answer will vary based on current research. Example: Discovery of a new hominid species or intermediate fossils between dinosaurs and birds.)

3. Attempt giving a clear definition of the term species.

• A species is a group of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups. Individuals of a species share a common gene pool and can produce fertile offspring.

4. Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference, etc.)

• Dryopithecus/Ramapithecus: ~15 mya; hairy, ape-like/man-like walking.
• Australopithecines: ~2 mya; walked upright, essentially fruit-eaters.
• Homo habilis: 650–800cc brain; first tool-maker, did not eat meat.
• Homo erectus: ~1.5 mya; 900cc brain, ate meat.
• Neanderthal Man: 1400cc brain; used hides, buried dead, lived in caves.
• Homo sapiens: Brain size ~1350cc; developed language, art, and agriculture.

5. Find out through internet and popular science articles whether animals other than man has self-consciousness.

• Research suggests that several animals show signs of self-awareness (passing the 'mirror test'), including chimpanzees, dolphins, elephants, and magpies.

6. List 10 modern-day animals and using the internet resources link it to a corresponding ancient fossil. Name both.

1. Horse - Eohippus (Hyracotherium)
2. Elephant - Moeritherium / Mastodon
3. Bird - Archaeopteryx
4. Whale - Pakicetus / Basilosaurus
5. Crocodile - Deinosuchus
6. Armadillo - Glyptodon
7. Camel - Protylopus
8. Tiger - Smilodon (Saber-toothed cat)
9. Shark - Megalodon
10. Giraffe - Samotherium

7. Practise drawing various animals and plants. (Student Activity)

8. Describe one example of adaptive radiation.

• Darwin's Finches: On the Galapagos Islands, Darwin observed many varieties of finches. They all evolved on the island from an original seed-eating ancestor. Due to different available food sources in different habitats (niche partitioning), their beaks adapted (insectivorous, vegetarian, wood-pecking, etc.), leading to the formation of multiple species from one.

9. Can we call human evolution as adaptive radiation?

• No. Human evolution is generally considered a case of anagenesis (directional change within a single lineage) or branching within a limited range, rather than a rapid radiation from a single point into many diverse ecological niches across a wide geography (like Australian marsupials).

10. Using various resources such as your school Library or the internet and discussions with your teacher, trace the evolutionary stages of any one animal, say horse.

• Evolution of Horse:
  1. Eohippus (Dawn Horse): Small, four-toed.
  2. Mesohippus: Larger, three-toed.
  3. Merychippus: Grazing habit developed.
  4. Pliohippus: First one-toed horse.
  5. Equus: Modern horse.