Importance of classification in eukaryotes

[Anithadhruvbud]

Eukaryotes are classified into unicellular and multicellular,what makes this classification so important?

 

[Ygggdrasil]

In my opinion, classifying eukaryotes as unicellular and multicellular is NOT a very useful classification. Classification in biology is most useful when the classification reflects the evolutionary history of the organisms—when organisms that descend from a common ancestor are classified together. Multicellularity has evolved independently multiple times, so classifying all multicellular organisms will lump together many evolutionarily unrelated organisms and separate some more closely related organisms. For example, multicellular fungi (e.g. mushrooms) are more closely related to unicellular yeasts than they are to multicellular plants. Similarly, unicellular yeasts are more closely related to multicellular fungi than they are to unicellular algae.

 

[jim mcnamara]

@Ygggdrasil is talking about are differences in the way taxonomists cubbyhole organisms.

His point is that using evolutionary (genetic) information to classify liging things is more useful and accurate - this is usually called phylogenetics. The idea that chimpanzees and modern humans share a large percent of their DNA -> an example.

Another way to classify is morphological. Lump everything that looks a lot alike into one pile. This approach used: structure of a flower, life cycles, skeletal structure, dentition in mammals. This has issues compared to the phylogenetic approach. What is the closest living plant to the lotus? Using the look alike system almost any scientist in 1980 would and did say - water lillies. DNA says something different. Plane tree is the answer. They DO NOT look much alike.

Kew gardens:
http://www.kew.org/science-conservation/plants-fungi/nelumbo-nucifera-sacred-lotus

Okay. So what has happened to classification? It has changed drastically in the past 25 years, think: the lotus thing.

Now we are down to unicellular versus multicellular. What do you suppose this tells us? A whole lot less than a taxonomist would have said 25 years ago. Some of these groups are considered more closely related than we thought before. Others that were previously lumped together have now become widely separated. The yeast-mushroom example (above post) is a good one in this context, too.

Direct answer to your question - you may be reading someone who follows an older approach. Or - for teaching beginner non-technical classes sometimes teachers do things like make 'things easy', rather than any other approach.

 

[Anithadhruvbud]

[USfundamentaYgggdrasil[/USER] is talking about are differences in the way taxonomists cubbyhole organisms.

His point is that using evolutionary (genetic) information to classify liging things is more useful and accurate - this is usually called phylogenetics. The idea that chimpanzees and modern humans share a large percent of their DNA -> an example.

Another way to classify is morphological. Lump everything that looks a lot alike into one pile. This approach used: structure of a flower, life cycles, skeletal structure, dentition in mammals. This has issues compared to the phylogenetic approach. What is the closest living plant to the lotus? Using the look alike system almost any scientist in 1980 would and did say - water lillies. DNA says something different. Plane tree is the answer. They DO NOT look much alike.

Kew gardens:
http://www.kew.org/science-conservation/plants-fungi/nelumbo-nucifera-sacred-lotus

Okay. So what has happened to classification? It has changed drastically in the past 25 years, think: the lotus thing.

Now we are down to unicellular versus multicellular. What do you suppose this tells us? A whole lot less than a taxonomist would have said 25 years ago. Some of these groups are considered more closely related than we thought before. Others that were previously lumped together have now become widely separated. The yeast-mushroom example (above post) is a good one in this context, too.

Direct answer to your question - you may be reading someone who follows an older approach. Or - for teaching beginner non-technical classes sometimes teachers do things like make 'things easy', rather than any other approach.

Well,My book says this basis of classification marks a fundamental difference in body design because of specialisation of cell types and tissues.
I think it more or less tells us that this basis has helped us to group organisms for knowing how they reproduce and do other life processes.
What do you think my book is trying to mean? Is my interpretation right?

 

[epenguin]

Eukaryotes are classified into unicellular and multicellular,what makes this classification so important?

To justify different University Departments