Question

10. Describe the characteristics of, and relationship between, the following: Gymnosperms,

Angiosperms, Coniferophyta, Ginkgophyta, Cycadophyta, Gnetophyta, Anthophyta, Monocots, Eudicots (Dicots).

8. What is the evolutionary importance of pollen grains?

can you please answer these two questions

thank you

Answer 1

ANGIOSPERMS also called flowering plants have seeds that are enclosed within an ovary usually a fruit.

GYMNOSPERMS also called cones have no flowers or fruits.they hav unenclosed or naked seeds on leave surface.

CONIFEROPHYTA also known as pinophyta/coniferae/conifers are division of vascular land plants.these r GYMNOSPERMS.

MONOCOTS or monocotyledon are seeds with one embryonic leaf or cotyledon.these are type of ANGIOSPERMS.

EUDICOTS/DICOTS-Most dicots have common pollen structure that differs from that of monocots and a minority of dicots; this large subgroup of dicots is called eudicots. A plant's pollen structure is what makes it a eudicot, but its seeds differ from those of monocots in the same way that the seeds of all dicots differ..eudi EUDICOTS have grooved structure in the pollen.eudicots also known as tricolpates.they have two cotyledons.

GINKGOPHYTA is highly unusual non-flowering plants.nearly all have been extinct except gingko biloba.

CYCADOPHYTA are actually gymnosperms,they have cylindrical trunks,leaves grow in rossette form.

GNETOPHYTA are type of gymnosperms(it includes conifers,cycads and ginkgos).the basic difference between GNETOPHYTA and other gymnosperms is presence of vessel elements for transporting water in the plants.

ANTHOPHYTA includes ANGIOSPERMS+GNETOPHYTA+extinct bennettitales.

The evolutionary importance of pollen grains from the beginning of time till now basically evolves around the successful process of pollination.(that is the transfer of pollen from a male plant to a female plant or within the same to enable fertilisation and later seed and fruit production).

So pollen grain shape-size-structure has to involve to overcome the change in environment (including temperature change),terrestrial adaption(that the pollen has to travel long distance),help with vector etc.