Artificial system of classification involves usage of one or few morphological characters.
Phylogenetic system plays important role in elucidation of evolutionary relationships.
DNA sequence is the basis of grouping organisms in – Chemotaxonomy
Chemotaxonomy involves grouping of organisms on the basis of :
Chemical nature of protein etc.
Plants which are not differentiated into roots, stems and leaves are Algae, Algae are thallophytes.
Cell wall of Spirogyra is composed of pectin and cellulose.
Kelps are massive brown algae.
Laminarin is the stored food in brown algae e.g., Dictyota.
Sexual reproduction in red algae is oogamous e.g., Gracilaria, Gelidium
Ectocarpus is branched filamentous brown algae
Carrageen – Red algae
Algin – Brown algae
Agar – Red algae
Single celled protein – Spirullina
Photosynthetic pigments in algae are present in chloroplast.
They are dependent on water for sexual reproduction
They usually occur in damp, humid and shaded localities
They play an important role in plant succession on bare rocks
The main plant body in bryophytes is haploid.
Peat is obtained from Sphagnum.
Liverworts reproduce asexually by gemmae and fragmentation.
Sphagnum is used for transportation of seedling of cut plants.
In mosses the sex organs are present in the leafy stage.
Antherozoids represent male motile gametes.
In pteridophytes, spores germinate to give rise prothallus.
In Selaginella the embryo develops into sporophyte.
In pteridophytes, the megaspore germinates to form female gametophytes.
Young embryos of pteridophytes within the female gametophyte – precursor to the seed habit.
Pteridophytes possess vascular tissues but lacks seeds. e.g., Ferns
In pteridophytes, gymnosperm and angiosperm ; The main plant body is sporophytes differentiated into true root, stem and leaves.
Pteridophytes, first terrestrial plants to possess vascular tissues.
In pteridophytes, fusion of gametes takes place in archegonium.
Gymnosperms are first seeded plants.
Gymnosperms have tap root system.
Pinus has both the male and female cones on same plant body Pinus is monoecious.
Gymnosperms possess (Naked seeds)
Coralloid roots have a symbiotic association with Nitrogen-fixing cyanobacteria.
The megaspore mother cell is differentiated from one of the cells of the Nucellus
The cones bearing microsporophylls are known as Male strobili.
Pollen grains are released from microsporangium.
In angiosperms the sporophylls are organised into flowers.
Wolfia is a microscopic angiosperm.
Endosperm of angiosperm is triploid (3n).
Fusion of a male gamete with the secondary nucleus forms the Endosperm
Triple fusion – Fusion of a male gamete with secondary nucleus
In angiosperms, female gametophyte is also known as embryo sac.
Double fertilization is an event unique to angiosperms.
Stigma functions as landing platform for the pollen grains in flowering plants.
Cells of embryo sac degenerate after fertilisation in angiosperms these are synergids and antipodal cells.
In angiosperms, the megasopre develops into embryo sac.
The germination of pollen grain results in the formation of pollen tube.
Cotyledons are embryonic leaves.
Haplo-diplontic condition is exhibited by Bryophytes
Haplontic life cycle is represented by Volvox
Fucus exhibits diplontic life cycle