Diversity In Living Organisms - II

Gymnosperms have naked seeds. The reproductive organs of plants (flowers) are inconspicuous (not visible). Therefore, they are also known as 'cryptogams'.  

Thallophytes – Algae belong to this division. 
Algae are photosynthetic and live mainly in water. For example, sea weeds. An alga does not have true leaves, roots or stems as compared to plants. Therefore, it belongs to division Thallophyta. 

Marsilea is an aquatic fern. The long-stalked leaves have four clover-like lobes and are held above water or are submerged. Marsilea belongs to pteridophyta.

Spores - Thallophytes, bryophytes & pteridophytes have naked embryos that are called spores.
The reproductive organs in these three groups are invisible and therefore they are called 'cryptogams' or “those with hidden reproductive organs”.

<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Presence of naked embryo - Thallophytes, bryophytes & pteridophytes have naked embryos that are called spores. 

Angiosperms - bear seeds that develop inside the organ, which is modified to become a fruit
Reason: Phanerogams - Plants with well differentiated reproductive tissues which ultimately make seeds. 

Phanerogams (Gymnosperm and Angiosperm) are the plants that reproduce by means of seeds and not by spores. They are the plants that produce seeds. 

Reason: In angiosperms, plant embryos in seeds have structures called cotyledons. Cotyledons are called 'seed leaves' because when they emerge during seed germination they become green. Thus, cotyledon represents pre-design plant in the seed. The angiosperms are divided into two groups based on the number of cotyledons present in the seed.
(1) Monocotyledonous or monocots - Plants with seeds having single cotyledon, e.g. Paphiopedilum
(2) Dicotyledonous or dicots - Plants with seeds having two cotyledons, e.g. Ipomoea. 

<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Algae are large and diverse groups of simple, typically autotrophic organisms ranging from unicellular to multicellular forms. They are photosynthetic, like plants and are called 'simple' because they lack many distinct organs (like stem, leaves) found in land plants. Alga is a non-vascular plant, i.e. without a vascular system (xylem and phloem). Non-vascular plants have no roots, stems or leaves. Since each of these structures contains vascular tissues. Hence, the correct answer is algae. 
<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Reason: Vascular tissue is a complex conducting tissue. The primary components of vascular tissues are xylem and phloem. These two tissues transport fluid and nutrients internally.

Thallophytes are characterised by the simple nature of their structure, i.e. undifferentiated thallus, which has no root, stem and leaf. Plants that do not have well-differentiated body design fall in this group. These plants are mostly aquatic. For example, Spirogyra, Chara, Ulothrix, Cladophora, etc.

Reason - The first level of classification among plants depends on well-differentiated distinct components of plants. For e.g. stems, roots, leaves.
The next level of classification is based on the presence of special tissues for transfer of water and other substances in differentiated plant body, i.e. the presence or absence of vascular bundles.
The final level of classification is based on the enclosure of seeds within fruits, i.e. the presence or absence of seed covering. 
Therefore, (4) is not the criterion as cell wall is present in all plants and is made of cellulose, which makes cell wall rigid.

<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Reason: Kingdom Plantae is divided into 5 groups.
<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">(1) Thallophyta   e.g. Algae like Spirogyra, Chara, Cladophora
<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">(2) Bryophyta     e.g. Marchantia and Moss
<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">(3) Pteridophyta e.g. Marsilea, Ferns and Horse tails
<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">(4) Gymnosperms          e.g. Pines, Deodar 
<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">(5) Angiosperms            e.g. all flowering plants potato, tomato, Brassica (e.g. mustard)

Pine is a gymnosperm. They have naked seeds, i.e. fruits do not enclose the seeds. Therefore, (3) is the correct answer. 

Pteridophytes include ferns and marsilea (aquatic fern). The long-stalked leaves have four clover-like lobes and are held above water or are submerged. 

Pine - is a gymnosperm. It bears seeds but the seeds are naked. 

They do not have specialized tissues for the conduction of water & other substances from one part of plant body to another, i.e. they lack vascular tissues. Roots are absent in bryophytes. Instead there are root-like structures known as rhizoids. 
Reason: Vascular tissue (xylem and phloem) helps in conduction of water and nutrients throughout the plant

'Gymno' means naked and 'sperm' means seed.
The plants of this group (1) have well-differentiated plant bodies (2) have vascular tissues and (3) produce seeds.
Although they produce seeds, but the produced seeds are naked. The seeds are not enclosed in ovaries as in flowering plants. They grow on the surface of modified leaf in a cone.

Rhizoids - are structures in fungi that function like roots in support or absorption. Bryophytes lack vascular tissues. In bryophytes, roots are absent instead there are root-like structures known as rhizoids. 

 Embryo - is a part of a seed consisting of precursor tissues for leaf, stem and roots. It is formed by multiple division of zygote.
In pteridophytes, embryos are not formed after zygote. Zygote directly gives rise to a young plant. No embryo stage is present in pteridophyte.

Pteridophytes do not produce seeds.
Reason: Ferns are pteridophytes. 

Reason: Flowering plants are called angiosperms.
A fern is an example of pteridophyte. It does not bear flowers.

Reason: In angiosperms, plant embryos in seeds have structures called cotyledons. Cotyledons are called 'seed leaves' because when they emerge during seed germination they become green. Thus, cotyledon represents pre-design plant in the seed. The angiosperms are divided into two groups based on the number of cotyledons present in the seed. 
(1) Monocotyledonous or monocots - Plants with seeds having single cotyledon, e.g Paphiopedilum
(2) Dicotyledonous or dicots - Plants with seeds having two cotyledons, e.g Ipomoea.

Paphiopedilum - is a monocot
Reason: Monocotyledonous or monocots - Plants with seeds having single cotyledon, e.g. Paphiopedilum.
Dicotyledonous or dicots - Plants with seeds having two cotyledons, e.g. Ipomoea.

Mango tree bears flowers and so it is an angiosperm.
Reason: Angiosperm is a flowering plant. 

<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Pteridophytes have specialized tissues for the conduction of water and other substances from one part of plant to another part. They bear primitive vascular systems, i.e. evolved for the first time in pteridophytes (e.g. ferns). 
<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Reason: Primitive - occurs at the first stage.

<span lang="EN-GB" style="line-height:" 150%;="">Reason: Dicot - 'Di' means two and 'cot' means cotyledons

Angiosperms: 'Angio' means covered and 'sperm' means seed, i.e. covered seeds. In angiosperms, seeds develop inside an organ, which is modified to become a fruit. Thus, seeds get enclosed within a fruit. 

Rhizoids - Mosses have root like rhizoids but these are not true roots because they do not have vascular systems. Dicots have tap root systems (straight roots that grow vertical downward) 

<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">They serve to absorb nutrients present in the seed until the seedling is able to produce first true leaves and then begin photosynthesis.

Mushroom belongs to the kingdom of Fungi. They are heterotrophic eukaryotic organisms as they derive their food from organic wastes. 

Flower - bears both reproductive parts for male (stamens) and female (ovary). Therefore, in angiosperms, reproductive organs aggregate in the form of a flower

Reason: Thallophytes, bryophytes and pteridophytes have naked embryos that are called spores. The reproductive organs in these three groups are invisible and therefore they are called cryptogams.
“Crypto” - hidden “gams” - gametes
<span style="font-family:" arial;="" font-size:="" 10pt;="" line-height:="" 150%;="">(1), (2), (3) cannot be the correct answer.
The correct answer is gymnosperms.
<span style="font-family:" arial;="" font-size:="" 10pt;="">Gymnosperms - The plants of this group bear naked seeds. Therefore, they are not called cryptogams and are called phanerogams.

The first level of classification among plants depends on the well-differentiated distinct components of plants, e.g. stem, roots and leaves. 

Pteridophytes have a well-developed vascular system and naked embryos called spores. The reproductive organs are very inconspicuous (not visible) and therefore, are called “cryptogamae” or “those with hidden reproductive organs”. Therefore, no formation of seed occurs. Thallophytes and bryophytes are also known as cryptogams, e.g. fern.  

The plants of this group bear naked seeds and are usually perennial (is a plant that lives for more than two years), evergreen and woody plants, e.g. Pinus, Deodar.

<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Thallophyte includes the plants that do not have well differentiated body designs. These plants are predominantly aquatic. The plants in this group are called algae, which have chlorophyll and can synthesize food by the process of photosynthesis.

Reason: Amphibian - means land animal that breeds in water
Bryophyte represents a unique group of plants intermediate between the predominantly aquatic thallophytes and terrestrial pteridophytes. They occupy and inhabit a zone, which is neither completely land nor completely water. It is for this reason bryophytes are often regarded as amphibians of plant kingdom. Like amphibians, bryophytes also can survive on land and require water for fertilization. 

<span lang="EN-GB" style="font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Times" new="" roman";mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:ar-sa="">Like other land plants, they have multicellular sex organs but do not bear seeds, e.g. mosses and marchantia.

Mode of nutrition is different in plants and fungi. Plants have autotrophic mode of nutrition as they prepare their own food whereas fungi are heterotrophic eukaryotes as they depend on other organisms for food. They depend on decaying organic matter for food.

Reason: Bryophyte represents a unique group of plants intermediate between the predominantly aquatic thallophytes and terrestrial pteridophytes. They inhabit a zone, which is neither completely land nor completely water. Thus, bryophytes are often regarded as amphibians of plant kingdom. Like amphibians, bryophytes can survive on land and require water for fertilization. Mostly, the plant body of bryophytes is differentiated to form stem and leaf like structures. However, there is no specialized tissue for the conduction of water and other substances from one part of the plant body to another. Examples are moss and marchantia. 

Marsilea - is an aquatic fern. As it is a fern, it belongs to pteridophyta.