Evolution, what, and any evidence is there?

Authors Avatar by eliotwood (student)


In this case study I will be writing about evolution and, what, if any evidence there is. I chose this topic of science because im interested in how our species came about and how it’s been changed from theory to theory, and how it’s still being challenged. This, I hope, will interest and reading group of KS4. This may or may not help them with there GCSEs and revision. After they have read my case study, I hope they will make up there own minds using the for and against evidence presented. I will also so show my own opinion at the end of the study along with a conclusion for for and against, I will also compare the sources that I present and evaluate them to see if they are backing up their claims.

Arguments for.

A general explanation of how scientists think it works.

This is an opening and explanation of evolution from Wikipedia: http://en.wikipedia.org/wiki/Modern_evolutionary_synthesis#The_modern_synthesis

 “The modern evolutionary synthesis (also referred to as the new synthesis, the modern synthesis, the evolutionary synthesis and the neo-Darwinian synthesis) is a union of ideas from several biological specialties which forms a logical account of evolution. This synthesis has been accepted by nearly all working biologists.[1] The synthesis was produced over about a decade (1936–1947), and the development of population genetics (1918–1932) was the stimulus. This showed that Mendelian genetics was consistent with natural selection and gradual evolution. The synthesis is still, to a large extent, the current paradigm in evolutionary biology.[2]

Julian Huxley invented the term, when he produced his book, Evolution: The Modern Synthesis (1942). Other major figures in the modern synthesis include R. A. Fisher, Theodosius Dobzhansky, J.B.S. Haldane, Sewall Wright, E.B. Ford, Ernst Mayr, Bernhard Rensch, Sergei Chetverikov, George Gaylord Simpson, and G. Ledyard Stebbins.

The modern synthesis solved difficulties and confusions caused by the specialization and poor communication between biologists in the early years of the 20th century. Discoveries of early geneticists were difficult to reconcile with gradual evolution and the mechanism of natural selection. The synthesis reconciled the two schools of thought, while providing evidence that studies of populations in the field were crucial to evolutionary theory. It drew together ideas from several branches of biology that had become separated, particularly genetics, cytology, systematics, botany, morphology, ecology and paleontology.


Summary of the modern synthesis

The modern synthesis bridged the gap between experimental geneticists and naturalists, and between both and paleontologists. It states that                  

1. All evolutionary phenomena can be explained in a way consistent with known genetic mechanisms and the observational evidence of naturalists.

2. Evolution is gradual: small genetic changes, recombination ordered by natural selection. Discontinuities amongst species (or other taxa) are explained as originating gradually through geographical separation and extinction (not saltation).

3. Selection is overwhelmingly the main mechanism of change; even slight advantages are important when continued. The object of selection is the phenotype in its surrounding environment. The role of genetic drift is equivocal; though strongly supported initially by Dobzhansky, it was downgraded later as results from ecological genetics were obtained.

4. The primacy of population thinking: the genetic diversity carried in natural populations is a key factor in evolution. The strength of natural selection in the wild was greater than expected; the effect of ecological factors such as niche occupation and the significance of barriers to gene flow are all important.

5. In paleontology, the ability to explain historical observations by extrapolation from microevolution to macroevolution is proposed. Historical contingency means explanations at different levels may exist. Gradualism does not mean constant rate of change.

The idea that speciation occurs after populations are reproductively isolated has been much debated. In plants, polyploidy must be included in any view of speciation. Formulations such as 'evolution consists primarily of changes in the frequencies of alleles between one generation and another' were proposed rather later. The traditional view is that developmental biology ('evo-devo') played little part in the synthesis, but an account of Gavin de Beer's work by Stephen J. Gould suggests he may be an exception.”

This source is not very reliable as its from Wikipedia, and Wikipedia is editable by anyone. But I have found another source that cross references it. Its from

http://www.talkorigins.org/faqs/modern-synthesis.html  By Laurence Moran.

And I think that this source is quite reliable and is a good cross reference to the first one. The web site also has other topics on it and links to other web sites that seem reliable as well. It has scientific explanations to link to its theory’s (the first source),  that don't just tell you what happens, but how and why, which lets grasp the full understanding of what they are explaining.

Reliability of Evolution.

The variety in life

 we can usually see the difference in most living things we see. But there are many there are many similarities in what we see. They all use DNA to pass on there genes. The differences come in what is known as variation. There are two types of variation, genetic and natural. Genetic is due to different allele combinations that you get from your parents, e.g your eye colour. Natural is due to changes that happen in your life like dying your hair.

This explanation is so the reader knows the difference between evolution and variation. This is by me and I learnt it in a lesson. The picture is from http://www.slh.wisc.edu/genetics/gene_02.gif

Questions and answers....

from “Twenty Fist Century Science, GCSE Science Higher” by David Brodie etco Published by Oxford University Press.

“Explaining similarities- the evidence for evolution”

“Most scientists agree that life on earth started from just a few simple living things. This explains why living things have so many similarities.

These simple things changed over time to produce all kinds of living things on earth today, the changes also produced many species that are now extinct. This process of change is called evolution, and its still happening today.”

Join now!

“What evidence is there for evolution?”

“Fossils are made from the bodies of living things. They are very important as evidence for evolution. Almost all fossils found are of extinct species. This is more than 99% of all species that ever lived on earth.”

“How reliable is fossil evidence?”

“Conditions have to be just right for fossils to develop. Only a very few living things end up as fossils. So there are many gaps in the fossil record. Sometimes a new species seems to appear without any in-between link to an earlier species.

   Although there ...

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Here's what a teacher thought of this essay


**** This quite an ambitious piece of work which attempts to review published material on the evidence for evolution as well as outlining the objections of opponents. In some cases the best use of available information sources has not been made but it is a creditable effort with very good evaluations of those sources used.