Group Consensus

We feel that natural selection would be a sufficiently valid explanation for the various relationships between the biodiversity of life on earth.

Firstly, fossil records provide direct evidence of evolution and detailed information on the ancestry of organisms. By looking at the fossil records, we would discover that organisms would tend to become more complex and the reason that is provided for this would be the continual change of the environment around them which results in their continual need for adaptation to the new conditions. This would serve to validate Darwin’s theory that organisms will have a struggle for existence due to the competition for the limited resources and would thus develop characteristics which would give them an edge over the rest and pass this on to future generations.

Also, homologous structures of organisms, for example the pentadactyl limb, are proof that they came from a common ancestor. To adapt to different environmental conditions unique to it, a gradual spreading of the homologous structure takes place in different organisms. Another example of homologous structures is the embryo. Species that look very different from each other in their adult form may have look similar in the embryonic stages, in the case of the human foetus. The gill-like structures and a “tail” which is present for a period of the time during its development, looks like those of a fish (in its embryonic development) and our primate relatives respectively. Hence, it can be said that humans and primates or humans and fish share homologous structures, even though they look different in their adult stages.

Next, there would be the example of the finches in support of Darwin’s theory. From his observations and study of the finches, he revealed that all the finches on the Galápagos Island descended from one original colonist species that adapted to a variety of feeding conditions went and that they eventually diverge into different species as they adapt to their different ecological niches. This would back Darwin’s theory that organisms will adapt to the environment due to the competition for resources and this advantage which they have gained would be passed down to their offspring which would in time result in the divergence of the finches into different species.

Aside from this, the example of the peppered moth (i.e. Biston betularia) where it shows how the dark-coloured moths would eventually dominate as compared to the light-coloured one as natural selection would favour them more.

Other prevailing theories were also rejected as they were proven untrue. For one, the theory of inheritance based on acquired traits by Lamarck was not supported by experiments. Even though this theory would provide an explanation for the biodiversity of life here on earth and his first statement s generally held to be true, experiments would serve to refute the second law he proposed — purely "acquired traits" do not appear to inherited by the offspring. (eg. a human child must learn how to catch a ball even though ancestors before him or her have learnt the same skill when they were children) However, there appears to be no substantial evidence refuting the theory of natural selection.

However, we feel that students should be exposed to the other current theories other than evolution, as they should understand that there is a variety of differing opinions and beliefs with regards to evolution. Also, they should understand that the theory of evolution, like science, is tentative and is subject to change with the development of science and research. Opposing theories such as Creationism, which focuses more on the religious aspect of human belief, should be briefly introduced in class so as to provide the students with the basic information of the prevailing theories in conflict with Darwin’s. Students should be encouraged to do their own research to better understand such other theories and their evidences. From there, students can be draw their own conclusions and form their own judgments and perspectives based on the newfound knowledge they have about evolution and its opposing theories.

Therefore, we feel that natural selection would be a sufficiently valid explanation for the various relationships between the biodiversity of life on earth and should hence be taught in science classes.