Key Points
Key Points: Division II - Angiosperms
- Angiosperms are flowering plants with seeds enclosed in fruits.
- They show great variation in size, from small (Wolffia) to large trees (Eucalyptus).
- Classified into monocots and dicots.
- Double fertilisation occurs, forming a zygote and a triploid endosperm.
- After fertilisation, the ovary becomes a fruit, and the ovule becomes a seed.
- Life cycle is diplontic with a dominant sporophyte and a reduced gametophyte.
Key Points: Morphology
- Homologous Organs - Same structure, different function; e.g. forelimbs of whale, bat, cheetah; indicate common ancestry and divergent evolution.
- Analogous Organs - Different structure, similar function; e.g. flippers of penguins and dolphins; do not indicate common ancestry; represent convergent evolution.
- Vestigial Organs - Non-functional remnants of ancestral organs; e.g. coccyx, nictitating membrane, appendix, wisdom teeth in humans.
- Molecular Evidence - Similarities in DNA, RNA, and proteins among diverse organisms indicate common ancestry.
- Homologous organs show divergence; analogous organs show convergence; together with molecular evidence, all strongly support organic evolution.
