Diversity in living organisms

Diversity in living organisms

17)                Gymnosperms, for e.g. pines and deodar, are phanerogams bearing naked seeds.

18)                In Angiosperms/flowering plants, the seeds are enclosed in fruits. 

19)                Cotyledons are present in the embryos of seeds.

20)                Monocot plants possess seeds with single cotyledons whereas dicots are plants with 2 cotyledons in seeds.

21)                Monocots show fibrous root system, parallel venation of leaves and flowers with three (or multiple of three) petals.

22)                Tap root system, reticulate venation of leaves and flowers with five (or multiple of five) petals are features of dicots.

23)                Organisms grouped under Animalia are eukaryotic, multicellular, heterotrophic and lacking cell walls.

24)                Animals are further divided into ten groups – Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, Protochordata and Vertebrata.

25)                In Porifera, also called sponges, the body is perforated by numerous pores and shows cellular level of organization. In addition, a hard exoskeleton and canal system are present. Sponges are non-motile. E.g. – Sycon.

26)                Coelenterates are radially symmetrical and show a cavity called coelenteron between epidermis and gastrodermis. Some like Hydra are solitary forms whereas others like corals live in colonies.

27)                Platyhelminthes includes the flat worms which are bilaterally symmetrical, dorsoventrally flattened, triploblastic and acoelomate. They may be free-living (e.g. Planaria) or parasitic (e.g. tape worm).

28)                The body of nematode worms is cylindrical, bilaterally symmetrical, triploblastic and pseudocoelomate. They are usually parasitic. E.g. Ascaris.

29)                Annelids are triploblastic, bilaterally symmetrical with true coelom and found in diverse habitats. Segmentation and extensive organ differentiation is seen. E.g. Earthworm and Nereis.

30)                The largest phylum of animal kingdom, Arthropoda, contains triploblastic, bilaterally symmetrical and segmented animals. These animals possess jointed legs and open circulatory system. E.g. Butterfly, centipede, crab, spider.

         In phylum Mollusca, (e.g. snail and Octopus) organisms show bilateral symmetry, soft body, open circulatory system and reduced coelom. 

More >>>