Samacheer Kalvi 8th Science Solutions Chapter 17 Pdf
Tamilnadu Board Samacheer Kalvi 8th Science Solutions Chapter 17: Tamilnadu State Board Solution Class 8 Science Chapter 17 – Plant Kingdom.
Samacheer Kalvi 8th Science Solutions Chapter 17: Overview
|
Board |
Samacheer Kalvi |
| Class |
8 |
|
Subject |
Science |
| Chapter |
17 |
|
Chapter Name |
Plant Kingdom |
Samacheer Kalvi 8th Science Solutions Chapter 17 Pdf
(I) Choose the best answer
(1) Solanum trilobatum is the binomial name of Thoothuvalai . The word ’Solanum’ refers to
a ) Species
b) Genus
c) Class
d) Orders
(2 ) Floridian starch is a reserve food material of
a ) Chloroplyceae
b) Phaeophyceae
c) Rhodophyceae
d) Cyanophyceae
(3) An example for colonial form of algae is
a ) Oscillatoria
b) Nostac
c) Volvox
d) Chlorella
( 4) One of the following is an edible mushroom
a ) Polyporus
b) Agaricus
c) Penicillium
d) Aspergillus
( 5) Plants that prevent soil erosion are
a ) algae
b) fungi
c) bryophytes
d) pteridophytes
( 6) The first land plants are
a ) bryophytes
b) pteridophytes
c) gymnosperm
d) angiosperm
( 7) The well- developed sporophytic plant body is seen in
a ) bryophytes
b) pteridophytes
c) gymnosperms
c) angiosperms
(8) Binominal Nomenclature was first introduced in the year
a ) 1970
b) 1975
c) 1978
d) 1623
(9) Penicillin is an antibiotic which is extracted from
a ) algae
b) fungi
c) bryophytes
d) pteridophytes
( II)Fill in the blanks
1 ) The word ‘ Taxonomy’ is derived from Greek word.
2 ) Binomial nomenclature was first introduced by Gaspard Bauhin .
3) The book ‘Genera Plantarum’ was published by Bentham and Hooker.
4) Monocotyledon seed bears only one cotyledon.
5) Brown algae belongs to Phaeophyceaeclass.
6) Agar Agar is obtained from red algae.
7) the reserve food material of fungi are glycogen and oil.
8) The first to land plant is Pteridophyte .
9) Xylem and phloem are absent in Bryophyteplants.
10) Reticulate venation is present in dicot plants.
(III) State true or false. If false correct the statement.
1 ) In polypetalae the petals are free .
This statement is true.
2) Binomial name should contain more than two words.
This statement is false.
Explanation:
Binomial name should not contain more than two words but rather, it should contain only two words.
3) Artificial system of classification is based on a few characters of the plant.
This statement is true.
4) Cell wall of fungi is made up of chitin.
This statement statement is true.
5) Pinus is a closed seeded plant.
This statement is false.
Explanation:
Pinus is not a closed seeded plant but rather ,it is a naked seeded plant.
6) All bryophytes are hydrophytes.
This statement is false.
Explanation:
All bryophytes are not hydrophytes but rather, all bryophytes are amphibians.
7) Dicotyledons have well developed characters then the gymnosperms.
This statement is true.
8) Mosses are the well developed plant in bryophytes.
This statement is true.
9) The dominant phase of the bryophytes is sporophyte.
This statement is false.
Explanation:
The dominant phase of the bryophytes is not sporophyte but rather the dominant phase of the bryophytes is gametophyte.
10 ) The dominant phase of the pteridophyte is gametophytic phase.
This statement is false.
Explanation:
Gametophytic phase is not the dominant phase of pteridophyte but rather, sporophytic phase is the dominant phase of pteridophyte.
(IV) Match the following .
| Cyanophyceae | Green algae |
| Chlorophyceae | Blue green algae |
| Phaeophyceae | Red algae |
| Rhodophyceae | Brown algae |
Answer
| Cyanophyceae | Blue green algae |
| Chlorophyceae | Green algae |
| Phaeophyceae | Brown algae |
| Rhodophyceae | Red algae |
(V) Answer very briefly .
1 ) Define- Thallus.
The term algae represents a latin word. They are simple, primitive plants containing chlorophyll. They are autotrophic in nature. Algae falls under the category of thalophyta and thallus refers to the plant body of algae. The plant body is not distinguished on the basis of root ,stem and leaf. Almost all the algae lives in marine water or fresh water. Most of them cannot survive in wet soil. As, these algae are extremely small in size, so they can easily float on the surface of water. These algae are known as phytoplankton.
2) What is meant by binomial nomenclature . Give example.
When an organism is named with two words, then it is called Binomial Nomenclature. As for example, Mangiferaindica represents the binomial name of mango. So, the first word Mangifera usually means the genus name and the second word indica means the species name. In 1623, Gaspard Bauhin first introduced the binomial name. It was Linnaeus, who implemented binomial system in his book , Species Plantarum. Botanical nomenclature refers to the procedure of naming plants on the ground of scientific basis.
3) Write any two characters of dicotyledons.
The two characters of dicotyledons are as follows :
- Seed contains only two cotyledons.
- Plants possess taproot system and leaves are arranged in such a way that they depict reticulate venation.
- Bean and mango are some of the relevant examples.
4) Seeds of gymnosperm plants are naked. Why?
As the ovule is not enclosed by ovary ,due to this reason, seeds of gymnosperm are naked. Gymnosperms possess two phases, i.e. Gametophytic and Sporophytic in its life cycle. Sporophytic plant body is distinguished on the basis of root ,stem and leaf and it is also dominant. They contains fully developed vascular tissues. Tracheid refers to the water conducting tissue and sieve cell refers to the food conducting tissue.
5) Write any two economic importance of fungi.
Antibiotic
Penicillin and Cephalosporin are mainly used for the purpose of treating several diseases and they are acquired from fungi.
Vitamins
Fungus such Ashbya gospii and Eremothecium goshbyiiare primarily used for the purpose of producing vitamin B2.
So ,the above points clearly portrays the economic importance of fungi.
(VI) Answer briefly.
1 ) Write a short note on the natural system of classification.
In this system, there is classification of plants on the grounds of different characters. As for instance, Bentham and Hooker’s classification depicts a perfect example of natural system of classification. This system of classification is mainly established on the ground of morphological and reproductive characters of the seeded plants. The natural system of classification was published in the book of Bentham and Hooker , named General plantarum in three volumes. Many herbaria and botanical gardens made use of this classification throughout the world.
2) Write any three economic importance of algae.
The three economic importance of algae are as follows:
- Food
Algae are mostly served as food in several countries like Japan, England and India. Ulva and Chlorellaportrays a relevant example. Some algae are also consumed by domestic animals. Laminaria and Ascophyllumare few such examples.
- Agriculture
Some of the blue green algae plays an important role in fixing nitrogen into the soil ,which in turn contributes in enhancing the fertility of the soil. Nostoc, Anabaena are some of the perfect examples.
- Agar Agar
Agar Agar is mainly used for the purpose of preparing growth medium in laboratories and it is obtained from some red algae like Gelidium and Gracillaria.
3 ) Write the differences between algae and fungi.
Algae
- Algae are autotrophic in nature .
- They contain pigments.
- Starch is mainly the food material that is reserved by algae.
- Some algae depicts prokaryotic nature. Cyanobacteria is one such example.
Fungi
- Fungi are heterotrophic in nature .
- They does not contain any pigments.
- Glycogen and oil are mainly the food materials that are reserved by fungi.
- Almost all the fungi are eukaryotic in nature.
4) How many classes are there in bryophytes ? What are they ?
Hepaticae (Liverworts) , Anthoceratae (Hornworts) and Musci ( Mosses) are mainly the three classes in which Bryophytes are categorized.
Hepaticae ( Example – Riccia)
- They represent a lower forms of bryophytes. They does not possess a complex structure in comparison to moss.
- Sprophytes does not live for longer period of time and they are extremely simple.
Anthoceratae ( Example – Anthoceros )
- Gametophyte falls under the category of undifferentiated thallus. Rhizoids contains a single cell and does not possess any branches.
- There is an absence of protonemal stage. Sporophyte is mainly distinguished on the basis of foot and capsule.
Musci ( Example –Funaria)
- They represent a higher forms in which the gametophyte is distinguished on the grounds of stem, leaf and root like structure.
- There is a presence of protonemal stage.
- Sporophytes are distinguished on the basis of foot, seta and capsule.
5) Write any four characters of pteridophytes.
The four characters of pteridophytes are as follows:
Pteridophytes
Pteridophytes are regarded as the first true land plants that contains xylem and phloem. Thus, they are known as vascular crytogams. The main plant body is distinguished on the grounds of true root, stem and leaves. Alternation of generation are also portrayed by pteridophytes. There is an alternation of the diploidsporophyticphase with the haploid gametophytic phase. Sporophytic portrays the dominant phase. Spores plays an important part in the reproduction of sporophytes. Sporangium manifests the structure in which spores are produced. Sporophyll refers to those leaves that contains sporangia.
(VII) Answer in detail .
2) Write any five differences between monocot and dicot plants.
Differences between monocot and dicot plants.
Monocotyledons
- Seed contains only one cotyledon.
- Plants possess fibrous root system and leaves are arranged in such a manner that they portray parallel venation.
- Flowers may be classified as trimerous.Calyx and corolla are not well differentiated.
- Wind contributes in the occurrence of pollination.
- Grass and banana are some of the important examples.
Dicotyledons
- Seed contains only two cotyledons.
- Plants possess tap root system and leaves are arranged in such a way that they depict reticulate venation.
- Flowers may be classified as tetramerous or pentamerous and are well differentiated into calyx and corolla.
- Insects plays an important role in the occurrence of pollination.
- Bean and mango are some of the relevant examples.
3) Write the differences between gymnosperm and angiosperm.
Gymnosperm
As the ovule is not enclosed by ovary ,due to this reason, seeds of gymnosperm are naked. Gymnosperms possess two phases, i.e. Gametophytic and Sporophytic in its life cycle. Sporophytic plant body is distinguished on the basis of root ,stem and leaf and it is also dominant. They contains fully developed vascular tissues. Tracheid refers to the water conducting tissue and sieve cell refers to the food conducting tissue.
Angiosperm
‘ Angio’ and ‘ sperma’ are the two Greek words from where the term ‘Angiosperm’ is derived. The word ‘ angio ‘ denotes box or closed and the word ‘ sperma’ denotes seed. Herb, shrub and tree are mainly the three habit of the plants. They possess highly developed vascular tissues and these tissues are known by the term of xylem and phloem. Xylem are mostly composed of vessel, tracheid, xylem parenchyma and xylem fibre and phloem on the other hand are composed of sieve tubes , phloem parenchyma , companion cells and phloem fibres.
4) Write the economic importance of gymnosperms.
The economic importance of gymnosperms are as follows:
- Paper industries makes use of the wood of numerous conifers. Pinus and Agathis are some of the examples.
- Conifers bears a crucial significance as they represent the source of softwood,that are mainly used for the purpose of construction and packing.They are also used in plywood industry.Cedrus and Agathis are few such examples.
- Turpentine is an essential oil that is mainly used in the preparation of paint and this oil is obtained from the resin of Pinus. It is also used for medicinal purposes ,as for instance ,it is very effective in reducing pain and acute chest cold.
- One can consume the seeds of Pinus gerardiana, as they are fit for human consumption.
- Ephedrine is an alkaloid that is mainly used for the purpose of treating asthma and respiratory diseases. This alkaloid drug is mainly acquired form Ephedra.
- Araucaria bidwilli is mainly grown as an ornamental plant.
5) Write the names of medicinal plants and explain their uses.
There are several usefulness of plants in our life. Some of the uses of medicinal plants are as follows :
Acalypha indica ( Kuppaimeni )
- It falls under the category of Euphorbiacea family .
- The paste that is acquired from the leaves of this plant proves to be very effective in curing the burns on the skin.
- In order to cure ringworm, the juice of this plant leaves is mixed with lemon juice.
Aegle marmelos ( vilvam)
- It falls under the category of Rutacae family.
- In order to treat the problem of indigestion, the unripe fruit of this tree is used to a considerable extent.
- It is also used for the purpose of treating chronic diarrhoea and dysentery.
Solanum trilobatum ( Thoodhuvalai )
- It falls under the category of Solanacea family .
- The leaves and fruits of this plant proves to be very effective in curing cough and cold.
- It is also used for the purpose of treating tuberculosis and bronchial asthma .
Phyllanthus amarus ( Keezhanelli)
- It falls under the category of Euphorbiacea family.
- Diseases like jaundice, can be cured by using this plant. So, this entire plant is very useful for treating this particular kind of disease.
- It contributes in keeping the human liver strong and healthy. It also renders tremendous support in the treatment of liver disorders.
Aloe vera ( Sothu katrazhai)
- It falls under the category of Liliaceae family .
- Leaves of this plant performs an essential role in the treatment of piles and helps to reduce skin inflammation.
- It is also used for curing peptic ulcer.