Classification Of Plant And Animals

                                           Classification Of Plants And Animals

Classification is the process of grouping the living beings into various groups and sub groups on the basis of similar and dissimilar characteristics.



The two importance of classification are:

1. It makes the study of plants and animals easier and systematic.

2. It gives us the idea about the evolution of plants and animals.

A genus is the group of closely related species.

A species is the group of closely related organisms having almost all similar characteristics which can interbreed freely and produce fertile offspring.

Nomenclature is the system of naming living organisms. The scientific way of assigning two names to an organism is called Binomial System of Nomenclature.

Taxonomy is defined as the branch of biological science that deals with the identification, nomenclature and classification of living organisms.

 Living things are classified into two kingdoms:
Plant Kingdom
Animal Kingdom

Plant Kingdom

On the basis of the flowering and non flowering, the plants kingdom are divided into two sub - kingdom.

Cryptograms: They are non flowering plants. On the basis of their appearance they are divided into three division thallophyta, bryophyte, and pteridophyta.

Phanerogams: Phanerogams are the developed seed bearing and flowering plants

It is further divided into two sub divisions:

 Sub division Gymnosperms:

They are cone bearing plants.

They grow in dry places.

They bear naked seeds.

Pollination takes place through wind.

Sub division Angiosperms:

They grow both in land and water.

They bear developed flowers.

Their seed are enclosed in true fruits.

They may be herbs, shrubs and trees.

Class monocotyledons:

A seed bears only one cotyledon.

Fibrous root is present.

Distinct nodes and inter nodes are present.

Leaves are elongated having parallel venation.

Class dicotyledons

A seed bears two cotyledons

Tap root is present

Distinct nodes and internodes are absent

Leaves are broad having reticulate venation.



Animal kingdom

All the animals different in size from unicellular to multicellular belongs to this group. Animal kingdom is divided into two sub-kingdom i.e.protozoa (unicellular) and metazoan(multicellular).

Metazoa: Metozoa is divided into different phyla

Phylum chordata:

The characteristics of phylum Chorodata are as follows:
Closed type of circulatory system is developed.
Heart is well developed and is ventrally placed.

These animals are unisexual.
Skull is developed and internal skeleton is covered with muscles.

Phylum chordata is further divided into four subphylum .they are:

Sub phylum Hemichordata

Sub phylum Urochordata

Sub phylum Cephalochordata

Sub phylum vertebrata

On the basis of adaptioncharacteristics, habitats vertebrates are categorized into two groups:

Poikilothermic (cold-blooded): Includes Pisces, amphibia and reptilia. These animals change their body temperature according to the environment.

Homoeothermic (warm-blooded): It includes aves and mammalia. These animals have constant body temperature.


Pieces

Characteristics:
They lay eggs and have external fertilization.
They have   long and streamlined body to reduce water resistance.

 Respiration takes place through gills.



Aves
Characteristics

Their fore limbs are modified into wings.
 Body is divided into head neck trunk and tail.

They have four chambered heart two auricles and two ventricles.

They have air sacs for easy flight.

Amphibia
Characteristics

 They have smooth and moist skin.
They are first land vertebrates.

They have 3 chamberedheart, two auricles and one ventricle.

Mammalia
Characteristics
They give birth to their babies directly and contain mammary glands.

Their sense organ is well developed and heart is four-chambered

They have external ears and pinnae.


Reptilia
Characteristics
Their outer surface is covered with dry, hard and horny scales.

Fertilization is internal

They have three-chambered heart.

They have pair of pentadactyle limbs with claws.

HALF THE UNIVERSE MISSING MATTER HAS JUST BEEN FOUND

Half the universe’s missing matter has just been finally found

The missing links between galaxies have finally been found. This is the first detection of the roughly half of the normal matter in our universe – protons, neutrons and electrons – unaccounted for by previous observations of stars, galaxies and other bright objects in space.

Two separate teams found the missing matter – made of particles called baryons rather than dark matter – linking galaxies together through filaments of hot, diffuse gas.

“The missing baryon problem is solved,” says Hideki Tanimura at the Institute of Space Astrophysics in Orsay, France, leader of one of the groups. The other team was led by Anna de Graaff at the University of Edinburgh, UK.


Because the gas is so tenuous and not quite hot enough for X-ray telescopes to pick up, nobody had been able to see it before.

“There’s no sweet spot – no sweet instrument that we’ve invented yet that can directly observe this gas,” says Richard Ellis at University College London. “It’s been purely speculation until now.”

So the two groups had to find another way to definitively show that these threads of gas are really there.

Both teams took advantage of a phenomenon called the Sunyaev-Zel’dovich effect that occurs when light left over from the big bang passes through hot gas. As the light travels, some of it scatters off the electrons in the gas, leaving a dim patch in the cosmic microwave background – our snapshot of the remnants from the birth of the cosmos.

Stack ‘em up
In 2015, the Planck satellite created a map of this effect throughout the observable universe. Because the tendrils of gas between galaxies are so diffuse, the dim blotches they cause are far too slight to be seen directly on Planck’s map.

Both teams selected pairs of galaxies from the Sloan Digital Sky Survey that were expected to be connected by a strand of baryons. They stacked the Planck signals for the areas between the galaxies, making the individually faint strands detectable en masse.

Tanimura’s team stacked data on 260,000 pairs of galaxies, and de Graaff’s group used over a million pairs. Both teams found definitive evidence of gas filaments between the galaxies. Tanimura’s group found they were almost three times denser than the mean for normal matter in the universe, and de Graaf’s group found they were six times denser – confirmation that the gas in these areas is dense enough to form filaments.

“We expect some differences because we are looking at filaments at different distances,” says Tanimura. “If this factor is included, our findings are very consistent with the other group.”

Finally finding the extra baryons that have been predicted by decades of simulations validates some of our assumptions about the universe.

“Everybody sort of knows that it has to be there, but this is the first time that somebody – two different groups, no less – has come up with a definitive detection,” says Ralph Kraft at the Harvard-Smithsonian Center for Astrophysics in Massachusetts.

“This goes a long way toward showing that many of our ideas of how galaxies form and how structures form over the history of the universe are pretty much correct,” he says.