Inter-relationships of classification, Biology

Assignment Help:

Inter-relationships of Classification

The aim of classification is to put together organisms on the basis of their similarities. But the question is what type of similarities? You know that fish and whales live in water; birds and butterflies live in air. Should we place fish and whales, in one group and birds and butterflies in another? Perhaps you are tempted to do so because fish and whales have organs to swim; birds and butterflies possess wings to fly. One of the early biologists, Pliny, in fact, classified animals on the basis of such analogous organs, that is organs that serve the same function and have similar appearance but have different evolutionary origins However, with the advancement in knowledge about the structure of animals it was revealed that the fish and whales or birds and butterflies have more differences than similarities between their body characters.

For example, fish respire using gills while the whales have lungs for this function. Similarly, birds have an internal skeleton whereas insects like butterflies lack it; instead they have an exoskeleton. Karl Linnaeus recognised these basic differences and based his system-of classification on the principle of homology. Homologous organs are those with the same evolutionary origin but which may not necessarily have the same appearance or serve the same function. For example, if you examine the fore-limbs of a man, the wing of a bat and the flipper of the whale (all mammals) you will see that in each case, though the function and the appearance of each of the fore-limbs are different, their basic skeletal plan is the same and they are homologous.

Furthermore, fossil records show that they all have a common evolutionary origin from the forelimbs of ancient amphibians. Thus, we conclude that all animals with pentadactyl forelimbs are related. Thus classification based upon homology reveals an inherent relationship among groups. In other words, it tells us that all creatures sharing basic structural features are related to each other and have evolved from a common ancestor.


Related Discussions:- Inter-relationships of classification

How different are oxyhemoglobin and hemoglobin, How different are oxyhemogl...

How different are oxyhemoglobin and hemoglobin? Where is it expected to find a higher concentration of oxyhemoglobin, in peripheral tissues or in the lungs? Oxygen-bound hemogl

Give a detailed account on central nervous system of frog, Question 1 Iden...

Question 1 Identify the specimen, class to which it belongs and write the salient features of that class.                                               Question 2 Write

Benefits of hand washing, Benefits of Hand washing You wash hands as a ...

Benefits of Hand washing You wash hands as a routine in daily life before cooking and eating food, after using wash room/toilet, before touching and caring a new born baby, aft

Explain enzyme inhibition, ENZYME INHIBITION Enzymes are often inhibite...

ENZYME INHIBITION Enzymes are often inhibited by  the presence of  suitable inhibitors. Much of current drug therapy  is based  on this. Basically, there  are  three major  cla

Explain composition of malt yeast peptone glucose medium, Explain Compositi...

Explain Composition of Malt Yeast Peptone Glucose Medium? Malt Extract - 3.0 gm Yeast Extract - 3.0 gm Peptone - 5.0 gm Glucose - 10.0 gm Agar - 15.0 gm Distille

Utalize the nonoxidative portion of the pentose phosphate, Under conditions...

Under conditions when a cell only needs to use the nonoxidative portion of the Pentose Phosphate pathway to synthesize ribose-5-phosphate, the elevated levels of NADPH in the cell

What are the main constituents of the earth atmosphere, What are the main c...

What are the main constituents of the earth's atmosphere in our time? The present atmosphere of the earth is constituted mostly of molecular nitrogen (N2) and molecular oxygen

Evaluating inducible ischaemia after revascularisation, Q. Evaluating Induc...

Q. Evaluating Inducible Ischaemia after revascularisation? Most early treadmill stress tests are performed either at discharge or within two weeks of an MI ard terminated with

Explain herbals of brunfels, Explain Herbals of Brunfels? Between the y...

Explain Herbals of Brunfels? Between the years 1530 and 1536 Otto Brunfelsius (Brunfels) (1463-1534) published his 'Herbal' which consisted of descriptions of a large number of

Ecology, Analyse the model that highlights the factors which influence the ...

Analyse the model that highlights the factors which influence the environmental impact of a population

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd