Question

1)Write brief notes on any two of the following: a) bryophytes b) ferns c) gymnosperms d) angiosperms 100 marks

2)What is a dichotomous key, and how can it be used in the study of plant diversity? 100 marks

about 2 pages each question. thank you

Answer 1

Answer:- a. Bryophytes :- These are an informal group consisting of three divisions of non-vascular land plants the liverworts, hornworts and mosses.They are characteristically limited in size and prefer moist habitats although they can survive in drier environments. The bryophytes consist of about 20,000 plant species.Bryophytes produce enclosed reproductive structures , but they do not produce flowers or seeds. They reproduce via spores. Their life cycle is dominated by gametophytic stage. They are found in various habitats like cold or hot deserts and near seas. They lack vascular system like roots to take nutrition directly from the soil.

b. Angiosperms:- These are seed bearing vascular plants. Their reproductive structure are flowers in which they enclose oules in an ovary. Angiosperms can be found in an extraordinary range of habitats, extending from saltwater to freshwater and from the tropics to polar regions. Structurally, they are adapted to a terrestrial environment, although some have become secondarily aquatic; other forms, such as the cacti, are able to tolerate exceptionally dry desert environments.  They include over half of the species of all plants and are found in a huge variety of land-based habitats in almost all parts of the world.

A dichotomous key is a tool created by scientists to help scientists and laypeople identify objects and organisms.

Typically, a dichotomous key for identifying a particular type of object consists of a specific series of questions. When one question is answered, the key directs the user as to what question to ask next.

Dichotomous keys typically stress identifying species by their scientific name, as each individual species has a unique scientific name.Dichotomous keys are very useful because they allow non-expert users to identify organisms by directing them to look at the known, important organisms.