Based on what you have observed in lab and learned in lecture, comment on the following claim
- \"all multicellular organisms can out-compete and out-survive all unicellular organisms because
they are more complex.\"
Solution
The formation of a living cell from organic molecules has taken a long way. The formation of
life from nonlife has greatest gap in the scientific theories of earth’s history. After the cooling of
earth, some 200 to 300 billion years ago, the water cells similar to modern bacteria were formed
from condensation of organic molecules into proteinoid microspheres under certain conditions.
These are not cells but have some characteristics of living systems. During the course of
evolution first, simple RNA molecules might have formed which later had the characteristics of
self replication, processing of other messenger RNA after transcription, helping in the replication
of DNA, catalyzing the chemical reactions and might have led to formation of systems consisting
of DNA directed protein synthesis.
The micro fossils discovered in the rocks more than 3.5 billion years old were the single celled
prokaryotic organisms resembling the modern bacteria. These must have evolved in absence of
oxygen. Over time, photosynthetic organisms might have evolved increasing the concentration of
oxygen in the atmosphere. This has caused some organisms to extinct because they could not
tolerate the high oxygen levels and some organisms to develop more effective metabolic
pathways to metabolize the oxygen.
The prokaryotic cells evolved earlier were started to develop internal membranes some 2 billion
years ago, due to which the evolution of eukaryotic cells had took place. The eukaryotic
organelles like mitochondria and chloroplast resemble the prokaryotic cells. This has happened
due to establishment of symbiotic relationship between prokaryotes that entered the eukaryotic
cells. Thus, endosymbiotic theory states that the eukaryotic cells are produced from living
communities formed by prokaryotic organisms.
The prokaryotes have small genomes and may contain less than 500 to more than 5000 genes.
The bacteria have a small circular chromosome and show specific variation with other bacterial
species. The bacteria contain extra chromosomal circular DNA called a plasmid. The plasmid is
capable of replicating on its own and often carries the non essential genes that can be transferred
from one cell to another. The bacterial genes are organized in to clusters known as operons that
can be transferred at a time. The genes of the operons contain protein encoding gene as well as
regulatory sequences. The gene density in the prokaryotes is one gene per kilo base.
The bacterial genomes highly differ with eukaryotic genomes in the aspects of gene density and
organization. The bacteria are single celled organism whereas the eukaryotes are multi cellular.
The eukaryotic genomes are large in size than the prokaryotes and may range 10 Mb to over 1
lack Mb. Prokaryo.
Based on what you have observed in lab and learned in lecture, commen.pdf
1. Based on what you have observed in lab and learned in lecture, comment on the following claim
- "all multicellular organisms can out-compete and out-survive all unicellular organisms because
they are more complex."
Solution
The formation of a living cell from organic molecules has taken a long way. The formation of
life from nonlife has greatest gap in the scientific theories of earth’s history. After the cooling of
earth, some 200 to 300 billion years ago, the water cells similar to modern bacteria were formed
from condensation of organic molecules into proteinoid microspheres under certain conditions.
These are not cells but have some characteristics of living systems. During the course of
evolution first, simple RNA molecules might have formed which later had the characteristics of
self replication, processing of other messenger RNA after transcription, helping in the replication
of DNA, catalyzing the chemical reactions and might have led to formation of systems consisting
of DNA directed protein synthesis.
The micro fossils discovered in the rocks more than 3.5 billion years old were the single celled
prokaryotic organisms resembling the modern bacteria. These must have evolved in absence of
oxygen. Over time, photosynthetic organisms might have evolved increasing the concentration of
oxygen in the atmosphere. This has caused some organisms to extinct because they could not
tolerate the high oxygen levels and some organisms to develop more effective metabolic
pathways to metabolize the oxygen.
The prokaryotic cells evolved earlier were started to develop internal membranes some 2 billion
years ago, due to which the evolution of eukaryotic cells had took place. The eukaryotic
organelles like mitochondria and chloroplast resemble the prokaryotic cells. This has happened
due to establishment of symbiotic relationship between prokaryotes that entered the eukaryotic
cells. Thus, endosymbiotic theory states that the eukaryotic cells are produced from living
communities formed by prokaryotic organisms.
The prokaryotes have small genomes and may contain less than 500 to more than 5000 genes.
The bacteria have a small circular chromosome and show specific variation with other bacterial
species. The bacteria contain extra chromosomal circular DNA called a plasmid. The plasmid is
capable of replicating on its own and often carries the non essential genes that can be transferred
from one cell to another. The bacterial genes are organized in to clusters known as operons that
can be transferred at a time. The genes of the operons contain protein encoding gene as well as
regulatory sequences. The gene density in the prokaryotes is one gene per kilo base.
The bacterial genomes highly differ with eukaryotic genomes in the aspects of gene density and
organization. The bacteria are single celled organism whereas the eukaryotes are multi cellular.
2. The eukaryotic genomes are large in size than the prokaryotes and may range 10 Mb to over 1
lack Mb. Prokaryotes contain a single chromosome and eukaryotes contain several. The
eukaryotic genes exhibit special characteristics like presence of non-coding or intervening
sequences or introns and repetitive sequences that are responsible for large genome size in
eukaryotes. The bacterial genes are organized in to polycistronic transcriptional units and do not
contain introns. In eukaryotes each individual gene is a transcriptional unit and contains introns.
This allows the reulation of genes and protein synthesis in eukaryotes.
Eukaryotic cells have started the sexual reproduction which allowed the evolution to take place
at a very speed rate. Many prokaryotic cells reproduce asexually, by simple duplication of
genetic material and by dividing in to two daughter cells. There is a least chance of genetic
variation to cause mutation in DNA in this type of reproduction. The sexual reproduction allows
the gene to shuffle in every generation during the formation of gametes due to which the crossing
over takes place resulting in great genetic variation. Thus, the offspring produced by sexually
reproducing organisms does not resemble their parents exactly. The increased genetic variation
in sexual reproduction increases the chance of evolutionary changes in a species due to the
natural selection.
Therefore, multicellular organisms can out-compete and out- survive all unicellular organisms
due to highly complex organization.
