Introduction to Biology(Botany)

By

Tejaswini chavan

For FYJC Science

Biology

• Botany:-The scientific study of the physiology, structure, genetics, ecology, distribution, classification, and economic importance of plants

• It is also known as plant science or plant Biology

• Examples algae, fungi, lichens, mosses, ferns, conifers and flowering plants.

Zoology:- It is also known as animal biology. Deals with only animals and human beings.

Chapters included (Botany)

1. Diversity in organisms

2. Kingdom plantae

3. Biochemistry of cell

4. Cell division

5. Morphology of flowering plants

6. Plant water relations and mineral nutrition

7. Plant growth

1 -Diversity in organisms

• Organisms differ in their form, structure and mode of living. Hence, based on their similarities they should be grouped.

• Grouping of organisms is known as classification.

• The study of biological classification is called taxonomy.

History of classification

Carolus Linnaeus classified all the living organisms into two kingdoms.

Robert Whittaker, in 1969 proposed ‘Five kingdom classification’ of living organisms.

Hierarchical classificationThe hierarchy can be represented as Kingdom subgrouping into Phylum for plants, Class, Order, Family, Genus and Species.

Nomenclature The scientific naming of an organism is called as nomenclature.

Five kingdom classification The five kingdom classification was proposed by R.H. Whittaker in 1969.

It includes Kingdom Monera, Kingdom Protista, Kingdom Fungi, Kingdom Plantae, and Kingdom Animalia.

Kingdom Monera:It includes prokaryotic cells lacking organised nucleus and membrane bound cell organelles.

Kingdom Protista: It includes algae, diatoms and protozoans.

These are unicellular and the simplest form of eukaryotes.

Kingdom Fungi:These are multicellular, eukaryotic saprophytes.

Kingdom Plantae:It includes all the plants that are non-motile, multicellular and eukaryotic organisms with their cell walls made up of cellulose.

Kingdom Animalia:It includes all the animals that are motile, multicellular, eukaryotic organisms with their cells possessing no cell walls.

• Lichens are composite, symbiotic organisms made up from members of as many as three kingdoms.

• Fungi are incapable of making their own food.

• Lichens are used for various purposes like in industry,medicines,as fodder, In food etc

Viruses and Viriods

The Term virus was first coined by Louis pasteur

• Viruses are acellular,host specific,and highly infectious.

• Viruses cause diseases to humans,plants,animals and bacteria.

• Viriods were discovered by Theodor Diener

• Viriods are small, circular, single standed RNAs without any protection. There is no protein coat. Viriods causes different diseases in plants.

2-Kingdom plantae

Cryptogamae:

• Cryptogams include all non-flowering plants such as algae, fungi, lichens, mosses and fern (Kryptos: concealed; gamus: marriage).

• Cryptogamae is further subdivided into three parts: Thallophyta, Bryophyta and Pteridophyta.

Thallophyta:

• Both Algae and Fungi are considered in Thallophyta, but nutrition in autotropic in algae, whereas fungi exhibit heterotropic nutrition.

Bryophyta:

• Bryophyta derives its name from mosses which grow on the rocks, walls and tree trunks in moist and shady places.

Pteridophyta:

• Pteridophyta derives its name from the fern.

Phanerogamae:

• Phanerogamae are also known as spermatophytes.

• Phanerogamae includes all flowering plants which bear seeds. (Phaneros: visible; gamus: marriage).

• Phanerogams are further subdivided into two parts: Gymospermae and Angiospermae.

Gymnosperms:

• Gymnosperms are represented by conifers, which grow in cool climate of hills, sometimes using melting snow as a source of water.

Angiosperms:• The angiosperms are seed-bearing plants .• Angiosperm plants represented by trees, shrubs and herbs are

either monocotyledons or dicotyledons. they have a body well differentiated into root, stem and leaves.

• There are two main classes of Angiosperms: a) Dicotyledonsand b) Monocotyledons.

Dicotyledons:• The leaves in members of Dicotyledons class exhibit reticulate

(net-like) venation and show varied arrangement like alternate, spiral or whorled.

• The seeds of dicotyledons are with two cotyledons.

Monocotyledons:• The leaves of Monocotyledons are simple with a parallel

venation. • The seeds have only one cotyledon.

3-Biochemistry of cell

• Plant Cell is a fundamental , structural, functional unit of plant.

• Carries metabolic activity

• Carbohydrates are produced by green plants.

• They have C,H and O group in ratio 2:1.

• They are Mono, Di and poly saccharide based on number of suger they contain.

• Proteins are long chain polymers of a.as in peptide linkages.

• Lipids have C, H ,O atoms in H:O proportion and less O.

• They are oily and greasy.

• They are simple,compound ,and derived lipids.

• Nucleic acids are components of nucleus.

• 2 types ie DNA ans RNA

• Enzymes –Help to speed up reaction and are Imp biochemical reactions.

• Amphoteric in nature

• Enzymes are proteins but all proteins are not enzymes.

4-Cell division

Cell division is the process by which a parent cell divides into two or more daughter cells.

• Mitosis is equational division

• Meosis is reductional division

5-Morphology of flowering plants

Root

Types of roots

leaf

Inflorescence

• inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches

• Racemose and cymose

Flower

Types of fruits

6-Plant water relations and mineral nutrition

• Water is essential for all life activities of plants

• Capillary water is the only water available for absorption.

• Roots absorb water by inhibition, diffusion and osmosis.

• 2 pathways ie apoplast and symplast.

• 2 mechanisms ie Active and passive.

• Cohesion theory is most widely accepted.

• Transpiration is loss of water from plants

• Stomata present in leaves causes loss of water.

• Stomata opens in day time.

• Stomata is closed during night.

• Transpiration helps in absorption of water, cooling of leaf, removes excess water.

• Translocation takes place through phloem.

• Plants need nutrients,10 macronutrients and 6 micronutrients.

• Nutients have important role in growth and development of plants.

• Inadequate supply of nutrients causes deficiency.

7-Plant growth

• Growth in plants is an irreversible increase in size, weight and volume of an organ of a plant.

• 3 phases

1. Formative phase

2. Elongation phase

3. Maturation phase

Growth phases plotted against time is callessigmoid growth curve.

• Growth regulators synthesized by plants

Photoperiodism is the response of an plant to seasonal changes in day length.

Vernalization