Biological Classification

Hello, readers! 

Today let's understand Classification of Living things.

Biological classification of plants and animals was first proposed by Aristotle. 

Linnaeus classified all living organisms into two kingdoms - Plants and Animals.

Robert whittaker proposed an elaborate five kingdom classification: Monera, Protista, Fungi, Plantae and Animalia. 

Monera: unicellular, prokaryotic, autotrophic or heterotrophic organisms. Eg bacteria

1. Archaebacteria: Halophiles, thermoacidophils, methanogens etc. 

2. Eubacteria: Autotrophic bacteria, heterotrophic bacteria etc.

Protista: unicellular, eukaryotic, autotrophic or heterotrophic organisms. 

1. Chrysophytes: plant like, golden algae and diatoms. 

Diatoms have soap-box like silica shells. 

2. Dinoflagellates: plant like, red, yellow, green, brown or blue cells. May have strong cellulose plates with two flagella. 

3. Euglenoids: plant like, has protein pellicle layer on cell. May have two flagella, a long and a short.

4. Slime moulds: fungus like, saprophytes, collectively called plasmodium - spores are formed for reproduction in unfavorable conditions. 

5. Protozoa: animal like, predators or parasites, 

Amoeboid protozoa, flagellated protista, ciliated protozoa and sporozoans.

Fungi:

Multicellular, eukaryotic, heterotrophic organisms. 

1. Phycomycetes: aseptate and coenocytic mycelium

2. Ascomycetes: mycelium is branched and septate, 

3. Basidiomycetes: mycelium branched and septate, 

4. Deuteromycetes: mycelium branched and septate, only asexual reproduction is discovered in them. 

Plantae: multicellular, eukaryotic, autotrophic organisms with cell wall of cellulose. Shows alternation of generation

Animalia: multicellular, eukaryotic, heterotrophic organisms without cell wall. 

Viruses, viroids, prions and lichens are not included in any of the five kingdoms. 

The Living World

Hello!

These are the important points on The Living World. 

Living organisms are self replicating, evolving and self regulating, interactive systems capable of responding to external stimuli. 

Metabolism, cellular organisation and consciousness are the defining characteristics of living things. While growth and reproduction are important characteristics but not defining characteristics of living things. 

Taxonomy includes the rules and principles for identification, nomenclature and classification of organisms. 

Binomial nomenclature is the most convenient and the most popular system. It was given by Carolus Linnaeus. 

The main taxonomic categories are: Kingdom, phylum or division, class, order, family, genus and species.

The taxonomical aids are: 

Herbarium, botanical gardens, museum, zoological parks and key.

Nilgai

Readers,

This is the largest antelope of this region. It is called blue bull or nilgai (Boselaphus tragocamelus). 

It is blueish-grey in colour and has horns, this means it is an adult male. The females and the young ones are of orange-tawny colour and don't have horns. 

These animals are seen solitary, in pair or in small herds. They often enter the farms and spoil the crop. 

Mustard

The Mustard (Brassica juncea) crop is grown in this region during winter. Their yellow flowers in the farm virtually change the farm into a garden; and the landscape becomes wonderful. 

Mustard oil is extracted from their seeds; and leaves can be used as green vegetable. 

Yellow-fruit nightshade

This plant is called yellow-fruit nightshade or कन्टकरी. Its botanical name is Solanum virginianum. This thorny herb grows in wild, on roadside and near farms. 

It bears beautiful, purple flowers and brinjal-like fruit. 

It is considered to be a poisonous plant. However, it has several medicinal uses also.

Factors Affecting Photosynthesis

According to Blackman's law of limiting factors, if a chemical process is affected by more than one factor, then the rate of reaction will be determined by the factor which is nearest to its minimal value.

Photosynthesis is affected by factors like light intensity, carbon dioxide concentration, temperature and water. 

1. Light: if light increases, photosynthesis also increases upto a certain level. Then it remains constant. Plants need only 10% of the available light intensity of sunlight. Therefore, light is never a limiting factor except in case the plant is in shade or in dense forest. 

If the light intensity increases too much, it starts destroying the chlorophyll, thus, photosynthesis reduces. 

2. Carbon dioxide: if amount of carbon dioxide increases, photosynthesis also increases upto CO2 concentration of 0.05 %. Then photosynthesis reduces. 

Saturation level or optimum level of carbon dioxide for C4 plants is 360 microlitre per litre of air; and for C3 plants is 450 microlitre per litre of air. Thus, carbon dioxide is a limiting factor more for C3 plants. 

3. Temperature: if temperature increases, photosynthesis also increases upto a certain level. Then photosynthesis reduces. C3 plants have lower optimum temperature (18 to 24 degree celsius). C4 plants have a little higher optimum temperature (30 to 40 degree celsius). 

4. Water: if available water is more, photosynthesis increases up to a certain level. Then there is no effect. If water available is less, the stomata do not open fully. So absorption of carbon dioxide is less. Thus, photosynthesis will also be less. 

Camels of Rajasthan (India)

These are the camels of Rajasthan. The zoological name of camel is Camelus dromedarius. These are very large, strong and handsome creatures. They are reared mainly for milk and to carry load. Once they were abundant in this area but now they are in crisis. Their number is decreasing and they now need support. 

Squirrel

This is a northern palm squirrel (Funambulus pennantii). It has five black-brown stripes on its back. It lives on trees. It is quite active and playful creature. Children like to observe it sitting, playing or searching for food. It doesn't sit in one place; though in summer, it likes taking rest on wet ground in the shade of a tree. 

Krebs' Cycle

Pyruvic acid which is produced in glycolysis is transported into the mitochondria where it is converted into acetyl CoA. Then, CoA enters the Krebs' cycle that takes place in the matrix of the mitochondria. 

NADH2 and FADH2 are generated in the Krebs' cycle. 

Glycolysis

In cellular respiration, oxidation of glucose takes place. The initial stage of cellular respiration takes place in the cytoplasm. Glucose molecule is broken down through a series of enzyme-catalyzed reactions into two molecules of pyruvic acid. This process is known as glycolysis.

Note: The above notes in the image(s) are taken from a personal notebook which was initially not intended to be shared online. Please excuse the rough handwriting and the spelling errors, if any.