Classification of Plants !

Plant Kingdom is divided into 02 broad categories

1) Cryptogams - Non Seed bearing plants
2) Phanerogams - Seed bearing plants

Cryptogams are further divided into the following :

1) Thallophyta
2) Bryophyta
3) Pteridophyta

Thallophyta
i) They are microscopic in nature.
ii) Plant body is not divided into roots, stem and leaves.
iii) Algae are grouped into Thallophyta.

ALGAE

1) Body may unicellular / multicellular.
2) They are mostly found in stagnant water.
3) They contain green pigment called Chlorophyll.
4) Brown and Red algae are found in sea water.
5) Brown Algae are called Kelp and can grow upto length of 60 metres.
 Examples are Spirogyra, Chlamydomonar and Volvex.

BRYOPHTA

1) They consist of multicellular plants
2) They are called " amphibians" of plant kingdom as they live on land and reproduce in water.
3) Commonly they are found in damp soil and bark of trees.
4) They have stem and leaves but not true roots.
5) They have thread like structures called Rhizoids which absorb water and minerals for the plant. Rhizoids also help plant to fix in soil.
Examples are Mosses and Liverworts

PTERIDOPHYTA

1) They are multicellular.
2) They are found in damp and shady trees.
3) They have well developed roots, stem and leaves.
4) They do not bear flower and seeds.
5) Their stem may be underground ( called Rhizome ) or above the ground.
6) Their leaves are called fronds.
7) Their leaves are divided into leaflets.
8) Lower side of the leaves bear rounded brown reproductive structure called Sori.

Example is Fern, Horsetails.



Phanerogams

They are divided into two categories:
1)Gymnosperms
2)Angiosperms


Gymnosperms;

1)Gymnosperms are mostly tall evergreen  trees growing on mountains.
2)Their seeds are not enclosed in fruits.
3)Their seeds are borne in cones.
4)Male cones produce pollens while female cones produce ovules which upon fertilization become seeds.
5)These plans have well-developed roots ,thick stems and needle like leaves.

Example:Cedar,Ginko.

Angiosperms:

1)They produce flowers and are also called flowering plants.
2)Fruits grow from flowers.
3)Their seeds are enclosed in fruits.
4)They are regarded as most advanced plants in plant kingdom and include all crop plants.

They are further divided into Monocotyledons and Dicotyledons

Monocotyledons:These plants bear seeds with one cotyledon-example maize ,rice.

Dicotyledons:These plants bear seeds with two cotyledons: example Gram, pea.

Plant Kingdom Classification

The 05 Kingdom system of classification

American Plant Biologist RH Whittaker in 1969 suggested the 05 kingdom classification of entire living world.

These are :

1) Monera

2) Protista

3) Fungi

4) Plantae

5) Animalia

Kingdom Monera 

1) It consists of unicellular organisms.

2) Organisms do not have well defined Nucleus

3) The cells have outer covering called Cell Walls

4) Some organisms are autotrophic like Blue-Green algae while some are hetrotrophic like Bacteria.

Bacteria can be of 03 different shapes

a) Spherical (Cocci)

b) Rod Like (Bacilli)

c) Sprial Shaped (Spirilla)

Examples are Strepto, Coccus and Ecoli

Kingdom Protesta

1) Organisms are unicellular.

2) Organisms have well defined Nucleus

3) They may be plant like. e.g. Euglena, Diatoms

4) They may be animal like e.g. Amoeba, Paramecium

5) Animal like Protists are called Protozoa

Kingdom Fungi

1) Organisms can be unicellular and multicellular.

2) They are heteriotrophic in nature.

3) The cells have a cell wall.

4) Some fungi are parasitic ( that is they obtain their food from other living organisms )

5) Some fungi are saprophtic ( that is they obtain theri food from dead and decaying  organisms )

6) They reproduce by spore formation, budding and fragmentation

7) They grow best where warmth and moisture are available

Examples are Moulds , Yeast and Mushroom

Kingdom Plantae

1) It consists of all multicellular green plants

2) They are autotrophic in nature.

3) Their cells have cell wall around them.

4)They are found on land, sea, lakes and streams

Examples are Mango Tree, Rose Plant , Grass etc

Kingdom Animalia or Animalae

1) It consists of all multicellular organisms

2) They are hetrotrophic in nature.

3) Their cells do not have cell wall around them.

4)They can be further divided into invertebrates and vertebrates
Examples are Hummingbird, Snake and Earthworm

Vertebrates Made Easy

Vertebrates - Animals having a distinct backbone are called Vertebrates. They are classified into 5 groups.

1) Picses ( Animals living in water )

A) They are found in aquatic habitat.
B) They are cold blooded animals.
C) They have streamlined body.
D) They breathe through gills.
E) Their body is covered with scales.

Examples are Sea Horse, Carp and Shark.


2) Amphibia ( Animals living on land and in water )

A) They are found in both on land and in water.
B) They are cold blooded animals.
C) They have thin moist and slippery skin.
D) They breathe with lungs when on land and through skin when in water.
E) They reproduce and lay eggs in water.

Examples are Salamander, Toad and Frog.


3) Reptilia ( Crawling Animals )

A) They are cold blooded animals.
B) Their skin is dry covered with scales.
C) Mostly they have 02 pair of legs.
D) They breathe through lungs.
E) They lay eggs with leathery shells.
Examples are Snake, Lizard and Crocodiles.


4) Aves ( Feathered Animals )

A) They are warm blooded animals.
B) Their body is covered with feathers.
C) Their fore limbs are modified into wings and hind limbs are modified for walking, swimming or perching.
D) Their bones have large air cavities.
E) They breathe through lungs.
F) They have horny beaks.
G) They lay eggs with hard shells.
Examples are Crow and Ostrich.


4) Mammalia ( Milk Producing Animals )

A) They are warm blooded animals.
B) Their body is covered with hair.
C) They breathe through lungs.
D) They have external ears, nose and specialized teeth.
E) They give birth to babies and produce milk for their nourishment.
Examples are Cat, Mouse, Lion and Humans.

Invertebrates made Simple !!

1) Poriferans (Sponges)

1.  They are found in sea / fresh water.
2. They are pore bearing animals having large number of pores in their bodies.
3. They obtain food and oxygen from water currents which enter the body through pores.
4. Waste is removed from the large opening present at the top.
5. They remain fixed to the sea floor.
6.They have radially symmetrical or asymmetrical body.

Examples are Sycon and Spongilla.

2) Coelenterata ( Cnidarians )

1.  They are found in marine environment.
2. They have radially symmetrical body.
3. The body is hollow, tube like.
4. Only one opening "mouth" is present.
5. The mouth is surrounded by tentacles.
6. Tentacles have stinging cells called cnidoblasts.
7. They either stick to some rock or float in water.
Examples are Hydra & Jellyfish.



3) Platyhelminthes (Flat worms)

1.  They are found in water or moist land.
2. They are simplest worms without legs.
3. Their body is flattened ribbon like.
4. They have bilaterally symmetrical body.
5. The body has one opening only.
6. Some flatworms are parasitic in nature and found in body of vertebrates.
7. Body cavity is absent. Examples are Tapeworm and Planaria


4) Nemathelminthes (Round worms)

1.  They are found in fresh/marine water or moist land.
2. Their body is bilaterally symmetrical.
3. The body has two openings, mouth and anus.
4. They have cylindrical unsegmented body.
5. Mostly, they are parasitic in nature.
6. They reproduce by laying eggs.

Examples are Pinworm and Ascaris

5) Annelids (Segmented worms)

1.  They are found in moist soil and pond water.
2. They have soft, cylindrical, segmented body.
3. Their body is bilaterally symmetrical.
4. Some are parasites in nature (leech).
5. They have special organs of excretion called nephridia.
6. They have a body cavity.

Examples are Earthworm and Leech


6) Arhtropoda ( Animals with jointed legs)

1.  They are found in air, on land and in water.
2. They have segmented body.
3. Their body is bilaterally symmetrical.
4. Thin body is divided into three regions - Head, Thorax and Abdomen.
5. They have jointed legs.
6. They have tough outer covering called exoskeleton.

Arthopods are furthter divided into four subgroups

A) Arachnida

1. Thorax and head region is fused.
2. Four pair of legs present.
3. Wings and antennae are not present
4. Hard exoskeleton is present.
Examples are Scorpions and Spiders

B) Crustacea

1. Thorax and head region is fused.
2. Appendages are present on all segments.
3. Variable number of legs present.
4. Two pair of antennae present.


Examples are Lobster and Shrimp

C)Myriapoda

1. Their body is divided into many segments.
2. Some have 02 pair of legs per segment. Example is millipede.
3. Some have 01 pair of legs per segment. Example is centipede.
4. Exoskeleton present.

Examples are Millipede and Centipede

D)Insects

1. The body is divided into three regions - Head, Thorax and Abdomen.
2. 03 ( Three ) pair of legs are present.
3.Two/One pair of wings may be present. Some insects are wingless too.
4. Mostly they have a pair of antennae.


Examples are Ants and Butterfly



7) Mollusca (Soft Bodies Shelled Animals)

1.  The body is soft unsegmented.
2. Often external hard shell is present.
3. Shell may be single, coiled or two shells are attached on one side.
4. Some have shell inside their body.

Examples are Octopus and Cuttlefish

 

8) Echinodermata (Spiny-skinnedAnimals)

1.  They are found in Marine habitat.
2. Their body is having radial symmetry.
3. Body is covered with sharp spines.
4.The body has two openings - mouth and anus.
5. Large number of tiny tube like feet are present which ends in suckers

Examples are Starfish and Urchin

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Digestion of Food in Human Body

The process of digestion of food begins in the mouth and is completed in small intestine.

Food in Mouth  -  In mouth starch is digested with the help of enzyme salivary amylase present in the saliva.

Starch Salivary amylase Maltose

Food in phayrx and esophagus -  No chemical digestion takes place in Pharyx and Esophagus.

Food in Stomch  -  Inside the stomach, food mixes with gastric juices which contain hydrochloric acid. Gastric juice kills bacteria and help in digestion of proteins with the help of 02 enzymes commonly known as Pepsin and Renin.

1) Pepsin acts on proteins and changes them to smaller molecules.

 Protein Pepsin  Proteoses + Peptones

2) Renin acts on milk protein casein and changes it to insoluble curd ( paracasein)

Casein Renin  Paracasein

Food in form of thick paste leaves stomach and moves to small intestine. This paste in called Chyme.


FOOD IN SMALL INTESTINE

Small intestine has 3 parts which are termed as duodenum, jejunum and ileum.

Duodenum : This part receives pancreatic juice from pancreas and bile from gall bladder.

Bile actually helps in breaking down the fats into tiny droplets.

It provides alkaline medium for action of enzymes.

Pancreatic Juice : It contains enzyme Trypsin and Lipase.

Trypsin : It acts on proteins proteoses and peptones and changes them to polypeptides

Proteins, proteoses and peptones Trypsin Polypeptides

Lipase acts on fats and change them to fatty acids and glycerol.  

Fats lipase fatty acids and glycerol

No chemical digestion takes place in Jejunum.

Ileum : In ileum following enzymes are present.

1) Erpsin

Peptones + Peptides   erpsin  amino acids

2) Maltase 

Maltose  maltase  glucose

3) Sucrase

Sucros    sucrase   glucose + fructose

4) Lactase

lactese   lactase  glucose + galactose

Digestion of proteins, fats and carbohydrates in completed in small intestine and they are absorbed in blood stream.

BIOLOGY MADE EASY - 6th Standard

BIOLOGY MADE EASY

Define Soil Profile

A vertical section of soil from surface down to the bedrock showing different layers (horizons) is call soil profile. A soil profile visually shown 03 regions

1)    A - Horizon

2)    B - Horizon

3)    C - Horizon

Define Fertilization

The fusion of male cell with the female cell (or egg cell) is called fertilization.

Define Node

The point on the stem from where the leaves and branches arise is called a node.

Define Weathering

The process of breaking down of huge pieces of rock and its minerals in fine particles by the physical, chemical and biological agents is called weathering. Depending upon the natural agents involved, weathering can be classified into 3 types:

1)    Physical weathering

2)    Chemical weathering

3)    Biological weathering

Define Lamina

The thin, flat and extended part of the leaf which is mostly green in color is called lamina.

Define Afforestation

The planting of more trees to reduce the loss of fertile top layer of soil is called afforestation.

One word for unweathered parent rock present below the C-horizon is Bedrock.

One word for the part of the flower that develops into seed is Ovule.

Largetst particle of soil is called as gravel.

The stalk that joins leaf to the stem is known as Petiole.

The part of the plant above the soil is called Shoot System.

Did you know that the leaves of Opuntia are reduced to pointed structures called spines to provide protection and reduce loss of water.

Why is clayey soil not very suitable for the growth of plants?

This type of soil is not very suitable for the growth of plants because water occupies the whole space between the particles as it has high water holding capacity and it becomes difficult for plants to respire due to lack of oxygen.

COMMUNICABLE DISEASES

COMMUNICABLE DISEASES

Diseases which spread from a sick person to a healthy person through food, water, air, insect bites or by direct contact are called communicable diseases. They are caused by microorganisms ( pathogens ) like bacteria, fungi virus and protozoa.

Some common types are given below

1.    Air borne Diseases : They are also called droplet infection as they spread through air. A diseased person carries germs of these diseases in his nasal passage, throat and mouth. Some examples are cold, flu, tuberculosis, measles and diphtheria.

2.   Water borne Diseases: They spread through contaminated water. Examples are typhoid, dysentery, cholera and intestinal infections.

3.   Contagious Diseases: These diseases are transmitted by direct contact with the patient. Examples are conjunctivitis and scabies. Sharing things like drinking glasses, towels and combs can also spread the infection.

4.   Vector borne Diseases: Diseases caused by microbes carrying organisms are called vector borne diseases. The insects and animals that carry disease causing germs are called vectors, such as flies, mosquitoes, fleas, pigs, dogs, ticks, mites etc.

Some of the diseases and their vectors are listed below :

DISEASE	VECTOR	PATHOGEN ( Disease Causing Agent )
Malaria	Anopheles mosquito	Protozoa
Dengue	Acdes mosquito	Virus ( DENV )
Typhoid	Housefly	Bacterium
Amoebic Dysentry	Housefly	Protozoan
Plague	Rat Flea	Bacterium
Rabies	Infect Dog	Virus