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Algae are known to reproduce asexually by a variety of spores under different environmental condition. Name these spores and the conditions under which they are produced.
Zoospores Flagellate spores, under favourable conditions. Aplanospores Non-flagellate, thin-walled spores under approaching unfavourable condition. Hypnospores Thick-walled, resting spores in unfavourable condition. Akinetes Thin-walled and thick-walled spores formed from whole cells in unfavourableRead more
Zoospores Flagellate spores, under favourable
See lessconditions.
Aplanospores Non-flagellate, thin-walled spores under
approaching unfavourable condition.
Hypnospores Thick-walled,
resting spores
in
unfavourable condition.
Akinetes Thin-walled and thick-walled spores formed
from whole cells in unfavourable conditions.
Autospores Spores which look exactly like parent cell
formed under favourable conditions.
Why the vascular plants dominated land?
The vascular plants dominated land due to the following features (i) Presence of deep, penetrating and widespread roots which anchor the plants and also absorb water and minerals. (ii) Covering of aerial parts with waterproof material like cutin. (iii) Mechanical tissues are present to allow them toRead more
The vascular plants dominated land due to the following
See lessfeatures
(i) Presence of deep, penetrating and widespread roots
which anchor the plants and also absorb water and
minerals.
(ii) Covering of aerial parts with waterproof material like
cutin.
(iii) Mechanical tissues are present to allow them to rise
to great heights.
What is the habitat of ferns. Describe their plant body. Explain the nature of spores ferns have. List out some common ferns.
Ferns are widely distributed all over the world in warm, moist and shady places. The main plant body of ferns is sporophyte, which is differentiated into underground stem called rhizome, roots and aerial shoots with leaves. Ferns are homosporous (e.g., Dryopteris, etc.) or heterosporous (e.g., MarsiRead more
Ferns are widely distributed all over the world in warm,
See lessmoist and shady places. The main plant body of ferns is
sporophyte, which is differentiated into underground
stem called rhizome, roots and aerial shoots with leaves.
Ferns are homosporous (e.g., Dryopteris, etc.) or
heterosporous (e.g., Marsilea). Spores are born in the
sporangia which are grouped in sori. Some common
ferns are Dryopteris, Pteridium, Pteris, etc.
Write a brief account of mosses.
Mosses are widely distributed from the Arctic through the tropics to parts of Antarctica. The gametophytic plant body is with leafy axis and shows a radial symmetry. The rhizoid are multicellular. branched and have Oblique septa. Sex organs. i.e.. antheridia and archegonia are usually borne in groupRead more
Mosses are widely distributed from the Arctic through
See lessthe tropics to parts of Antarctica. The gametophytic
plant body is with leafy axis and shows a radial
symmetry. The rhizoid are multicellular. branched and
have Oblique septa. Sex organs. i.e.. antheridia and
archegonia are usually borne in groups at the apices Of
reproductive branches. The sporophyte is usually
differentiated into toot, seta and capsule.
What is the most common liverwort? Draw its well-labelled diagram. What is the nature of its thallus?
The most common example of liverworts is Marchantia. The vegetative plant body of Marchantia is a dorsiventral lobed thallus.
The most common example of liverworts is Marchantia.
See lessThe vegetative plant body of Marchantia is a dorsiventral
lobed thallus.
Describe the type of photosynthetic pigments in red algae, green algae and brown algae.
Red algae The photosynthetic pigments are located in the chromatophores are chlorophyll-a. d, and a, lb-carotenes. xanthophyll and biliproteins. Green algae Chromoplasts contain chlorophyll-a, b. carotene and xanthophyll.
Red algae The photosynthetic pigments are located in
See lessthe chromatophores are chlorophyll-a. d, and
a, lb-carotenes. xanthophyll and biliproteins.
Green algae Chromoplasts contain chlorophyll-a, b.
carotene and xanthophyll.
Which characters are used in natural system of classification? Explain with examples.
The characters used in natural system of classification are morphology, anatomy, reproduction, cell structure, behaviour and biochemistry. The similarity in large number of characters show kinship. Examples (i) Monocotyledons have one cotyledon in their seeds and their leaves have parallel venation.Read more
The characters used in natural system of classification
See lessare morphology, anatomy, reproduction, cell structure,
behaviour and biochemistry. The similarity in large
number of characters show kinship.
Examples
(i) Monocotyledons have one cotyledon in their seeds
and their leaves have parallel venation.
(ii) Dicotyledons have two cotyledons in their seeds and
their leaves have reticulate venation.
Describe the salient features of artificial classification systems.
Salient features of artificial classification system are (i) They uses only gross superficial morphologic' characters such as habits, colours, numbers and shapes of leaves, etc. (ii) These consider mainly the vegetative characters androecium characters as given by Linnaeus. (iii) They separated closRead more
Salient features of artificial classification system are
See less(i) They uses only gross superficial morphologic’
characters such as habits, colours, numbers and
shapes of leaves, etc.
(ii) These consider mainly the vegetative characters
androecium characters as given by Linnaeus.
(iii) They separated closely related species.
Why are bryophytes called as amphibians of plant kingdom?
Bryophytes are terrestrial plants. But, they need water for completion of their life cycle. The external water is required for dehiscence of antheridia, liberation antherozoids, transfer of antherozoids from antheridia W archegonia, etc. Rest other stages Of life cycle are terrestrial. so they are cRead more
Bryophytes are terrestrial plants. But, they need water
See lessfor completion of their life cycle. The external water is
required for dehiscence of antheridia, liberation
antherozoids, transfer of antherozoids from antheridia W
archegonia, etc. Rest other stages Of life cycle are
terrestrial. so they are called amphibians of plant
kingdom.
Vascular tissues are not present in bryophytes. Then how the conduction of water and food takes place?
Vascular tissues, i.e., xylem and phloem are absent in bryophytes. The conduction of water and takes place from cell to cell by diffusion,
Vascular tissues, i.e., xylem and phloem are absent in
See lessbryophytes. The conduction of water and takes
place from cell to cell by diffusion,