Practice Questions

Haploid gametophyte is the dominant phase in the life cycle of liverworts. Diploid sporophyte, diploid zygote and diploid spores are short living intermediary structures that finally result in gametophyte.

Sporophyte contains mainly of three parts capsule, seta and foot. Capsule is the portion of sporophyte that bears spores and seta is the part that transfers water and nutrients from gametophyte to capsule.

Most of the leafy liverworts resemble mosses in their structure. Leafy liverworts contain oil bodies that are absent in mosses. Leafy liverworts contain lobes in their leaves whereas don’t mosses. In mosses, leaves are spirally arranged but in leafy liverworts leaves grow in two or three rows.

Most of the leafy liverworts resemble mosses in their structure

Liverworts contain oil bodies that are absent in mosses

Moses contain lobes in their leaves whereas leafy liverworts don’t

In mosses, leaves are spirally arranged but in leafy liverworts leaves grow in two or three rows

Bryophytes hold soil firmly and therefore prevent soil erosion. Bryophytes decompose barren rocks and make soil fertile. Bryophytes are used as packing materials and as good fuel. Bryophytes are good absorbers of water and can’t be used for packing of food materials.

Bryophytes decompose rocks and make soil fertile

Bryophytes are used in packing materials and are also good fuel

Bryophytes don’t absorb water and are used to pack food materials

Bryophytes are called as plant amphibians. Although they can manage to grow on land in normal conditions, water is essential for them to transmit male gametes to female gamete in order to facilitate reproduction.

Because they grow in water during summer and on land in winter

Because they grow on land but water is necessary for them to reproduce

Because they grow in water during first half of the year and on land in the second half of the year

Because they grow in water in north part of world and on land in southern part of the world

Sphagnum belongs to bryophytes and to the sub-classification of mosses. Sphagnum has a very good commercial importance and is used in the packing of cookery and glass materials.

In fragmentation, leaves/stems fall off accidentally and grow to form new individuals. Budding is a process in which an outgrowth develops and splits from the parent thallus to produce new individual. Gemmae are tiny, multi-cellular structures that can detach from the parent plant and grow into a new individual. Sporophyte develops from a developed embryo and results in the formation of spores. Sporophyte formation is a sexual process that involves two gametes and hence it is not an asexual process.

The female sex organs in bryophytes are called archegonium and they produce female gamete called egg. The male sex organ is called antheridium and produce male gametes called antherozoids.

Bryophytes are sub-classified into liverworts and mosses. Bryophytes are mostly found in moist hilly areas. Bryophytes don’t contain vascular tissues to transmit water and therefore don’t grow tall. Bryophytes follow cryptogamae.

Bryophytes are sub-classified into liverworts and mosses

Bryophytes are mostly found in dry hilly areas

Bryophytes don’t contain vascular tissues to transmit water and therefore don’t grow tall

Bryophytes are erect with hair like structures called rhizoids. Rhizoids anchor bryophytes to the soil and help in transfer of nutrients from soil to the thallus. They are also called virtual roots of bryophytes.

Phycoerythrin and phycocyanin are biloproteins present in Rhodophycophyta. They are also present in cryptomonads.

Chlorophyll d is present only in the members of Rhodophycophyta. There are five chlorophylls a, b, c, d, e which are found in different organisms.

Phaeophycophyta or the brown algae consists of two lateral flagella. Dinoflagellate or cryptomonads also consists of two lateral flagella.

Bacillariophycophyta or diatoms produce shells (cell walls) containing silica, some of which are very beautiful. Shells of diatoms are called frustules.

The xanthophye walls are typically of cellulose and pectin. The cellular storage product is an oil or (a branched glucan) chrysolaminarin.

Rhodophycophyta reproduces sexually heterogamously by the union of well-differentiated nonmotile male and female germ cells, the spermatia and carpogonia (female sex organs), respectively.

Brown algae are structurally quite complex and kelps belong to this group. Kelps are large, the individual plants reaching a length of several hundred feet.

The chloroplasts of green algae often contain dense regions called pyrenoids, on which surface starch granules are formed.

Volvox is a colonial green alga which may form water blooms. Its colonies are visible to the naked eye.

Sexual reproduction occurs in many species of Chlamydomonas, by isogamy, heterogamy, or oogamy in which isogamy is by far the most common. The zygote divides to form four or eight motile haploid cells are released.

Chladophora is a filamentous branched algal. Chladophora is also called river weed in some areas. It is edible. There are many different varieties of chladophora that are difficult to be classified. Ulva are also called as sea lettuce since they are used in salads.

Chladophora is a filamentous branched algal

Chladophora is also called river weed in some areas

There are many different varieties of chladophora that are difficult to be classified

Spirogyra contains two cellular layers. The outer cellular layer is made of Pectin. The inner cellular in spirogyra is made up of Cellulose. This double cellular layered structure helps them to withstand osmotic pressure.

Plants are classified as Thallophyta and others based on their well differentiable structure. Plants whose structure can’t be differentiated are put under the category of “Thallophyta”.

plants that don’t have well-differentiable structure

The vegetative cells in Phaecophyceae are made up of two layers with the inner one being made of cellulose and the other being made of gelatinous coating of algin. A leaf like photosynthetic organ in Phaecophyceae is called as frond. They also have a stalk called stipe and a substratum called as holdfast.

In Phaecophyceae, food is stored in the form of complex carbohydrates like laminol and manitol. Sometimes food is also stored as oil droplets in phaecophyceae.

Gelidium and Gracilaria is used in the formation of Agar. Agar is used in the preparation of ice-creams and jellies. Apart from the preparation of ice-creams, agar has different uses in both industries and in research.

Multiple fission is a process through which many individuals are produced by repeated nuclear division. Multiple fission takes place under unfavourable conditions. During multiple fission, an outer layer called cyst is formed. Nucleus divides repeatedly and new individuals are formed inside the cyst after which cyst breaks to release new individuals.

Multiple fission is a process through which many individuals are produced by repeated nuclear division

Multiple fission takes place under suitable conditions

During multiple fission, an outer layer called cyst is formed

Nucleus divides repeatedly and new individuals are formed inside the cyst after which cyst breaks to release new individuals

During unfavourable conditions, an outer layer that is formed outside chlamydomonas is called cyst. These unfavourable conditions allow multiple fission inside the cyst.

In fragmentation, a parent organism breaks into a fragment and each fragment gives a new individual. Spirogyra uses fragmentation to reproduction.

In chlorophyceae, chloroplasts contain storage bodies called Pyrenoids. Pyrenoids consists of proteins and starch. Chlorophyceae sometimes store food as oil droplets.

Algae help in increasing oxygen levels in the environment. Chlorella and Spirullina are multi-cellular algae that are rich proteins and are used as food supplements for space travelers. Chlorophyceae comprise algae that contain chlorophyll a and chlorophyll b. Chlorophyceae store food as proteins, starch or as oil droplets.

Algae help in increasing oxygen levels in the environment

Chlorella and Spirullina are multi-cellular algae that are rich proteins and are used as food

Chlorophyceae comprise algae that contain chlorophyll a and chlorophyll b

Chlorophyceae store food as proteins, starch or as oil droplets

In oogamous mode of reproduction, the larger gamete is non-motile and smaller gamete is motile. In humans, sperms being the smaller gamete are motile and the egg being the larger gamete is non-motile. Therefore, reproduction in humans is an example of oogamous reproduction.

Most of the algae reproduce using spore formation. Asexual spores are called as zoo-spores and the reproductive part in algae is called zoosporangium. Under favourable conditions, these organisms germinate to form new organism. Zoo-spores are motile and flagellated.

Most of the algae reproduce using spore formation

Asexual spores are called as zoo-spores and the reproductive part in algae is called zoosporangium

Under favourable conditions, these organisms germinate to form new organism

Zoo-spores are non-motile and flagellated

Volvox grows in colonies. The structures that connect them are called cytoplasmic bridges. Daughter colonies of volvox grow inside the parent colony. They contain flagellum that facilitates their movement.

The structure that connects them are called cytoplasmic bridges

Daughter colonies of volvox grow inside the parent colony

They are immobile due to absence of flagellum

Ulva is a multicellular algal that grows on moist rocks and walls. It is edible and is used as salad leaves. It is also called as sea lettuce. It has 2 layers of irregularly arranged cells.

Ulothrea are multicellular autotrophic algae. Chlamydomanas is an example of unicellular algae. Chlamydomanas have flagella to promote their movement. Spirogyra attains its name because of spiral like arrangement of chloroplasts.

Chlamydomanas is an example of unicellular algae

Chlamydomanas have flagella to promote their movement

Ulothrea is a unicellular autotrophic algal

Spirogyra attains its name because of spiral like arrangement of chloroplasts

Artificial classification is based on morphological structures of the plant i.e. artificial classification focuses on external structure of the plants than their internal structure.

Natural classification overcomes the limitations of the plants. Both internal and external structures are considered to be the basis of natural classification. Natural classification considers reproductive mode, embryotic structure and ultra structure of plants. It establishes close relationship between plants.

In natural classification, only internal structures of the plants are considered

Natural classification overcomes the limitations of the artificial classification

Natural classification considers reproductive mode, embryotic structure and ultra structure of plants

Natural classification establishes close relationship between plants

Phylogenetic classification considers evolutionary relationships between organisms. Fossil records, cytotaxonomy, chemotaxonomy and numerical taxonomy help in studying their evolutionary structures.

Numerical classification is based on mathematical calculations based on observable characteristics. In this mode of classification, each character is given a number or a code. The more the number of similar characters, the more is the chance that they belong to similar taxon. The main disadvantage of numerical taxonomy comes with the variation in result with variation in set of characteristics.

Numerical classification is based on mathematical calculations based on observable characteristics

The more the number of similar characters, the more is the chance that they belong to similar taxa

Numerical taxonomy gives the same result irrespective of the different sets of characteristics considered

Cytotaxonomy is based on the chromosomes present in the organism. Cytotaxonomy involves both internal and external characteristics of plant. Cytotaxonomy involves characteristics like number of chromosomes, division of cell and position centromere. Chemotaxonomy is based on the chemical composition of plants.

Cytotaxonomy is based on the chromosomes present in the organism

Chemotaxonomy is based on the chemical composition of plants

Cytotaxonomy involves characteristics like number of chromosomes, division of cell and position centromere

Cytotaxonomy involves only external characteristics

The mode of classifying plants as shrubs, herbs and trees come under artificial classification. In this mode of classification, morphological characteristics of plants are considered to be the basis of classification.

Serpentine layering is a propagation technique that involves burying and exposing sections of a plant's stem to encourage roots to form at multiple points, resulting in multiple new plants. It's similar to simple layering, but with more than one section of the stem covered and exposed

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