How is the science of Charles Darwin different then the science of today?

Question

yes, it is for a research paper and i really need help.

Answer 1

Darwin and people since him, up until DNA was available, looked at structural homologies of animals. That means they made phylogenies, evolutionary "tree's of life", looking at similar anatomies in animals. They didn't look & compare how the structures were used. They looked & compared the structures themselves. For example, flight didn't group a bird and a bat together. Birds fly with their arms. Bats fly with their fingers. Therefore, birds and bats are not homologous.

Them came along Mendel who introduced genetics and alleles. He didn't have access to DNA sequencing though, he only made observations from various seeds and plants he grew.

Now...DNA is pretty easy to obtain, to sequence, and then to compare, I've done it four quarters in a row.

Science is moving to cladograms. I had my first crack at this last quarter in botany. They are similar to the old school tree's of life, however they offer more information and it is based on DNA sequences (genetics), rather than just observations of anatomical structures.

It is interesting to see how the DNA sequenced cladograms match up, or don't with the old school method.

Darwins theories have been revised to fit new observations. The areas of Darwin's theories that are widely accepted are perpetual change, common descent, and multiplication of species (a.k.a. speciation).

Perpetual change = the millions of fossils are remains of long extinct animals. If you research the Burgess shale, which is in British Columbia, you'll find lots of info on fossils.

Common descent is seen in the phylogenies and cladograms.

Multiplication of species = when one species changes into another and the new species can no longer mate with the old species (different species can't reproduce with eachother)

The areas that are currently being argued over are gradualism and natural selection. It isn't quite sure how it happens.

Gradualism implies that species will multiply into other species gradually, over a long period of time. Scientists have seen it happen in fish in 14 years. Scientifically, 14 years isn't a long time.

Natural selection: for this you can research the famous pepper moths. The thing scientists are debating is how natural selection occurs. According to Darwin, a peacock should not survive, they should be extinct. The peacocks' feathers, with its eyes on the feathers, are an easy target for prey. It should be eaten and peacocks should be extinct by now. So something is going on. It's believed that the beautiful feathers attract a mate. The peacock gets to reproduce before it is eaten, that's what the hope is. So I imagine natural selection needs some modifications to include this situation with the peacock...

These are all generalizations and you could find enough information to meet however many pages it is you need in your report. Other revisions to Darwins' theories are: Genetic equilibrium which Hardy-Weinberg came up with...their equations showed that allele frequencies should remain constant in large populations...that means Mendelian genetics alone do not account for evolution...there shouldn't be much of a change in animals. However, there is...so some revisions since Darwin are:

genetic drift
nonrandom mating
migration

look them up and have fun =P

Ohhh! before I forget the major discovery within the last 20 years are homeobox genes (HOX genes). Look that up. Basically the HOX genes turn other genes on or off. A change in the TIMING of development can lead to evolution. My professor said scientists have been able to grow functional eyes on elbows, functional legs growing on a flys head...crazy stuff. I haven't researched it myself, but I'm learning about them. He said that all animals have HOX genes so it explains how animals can get new and/or more body parts. I know the examples I gave are freaky and I'm curious to see videos of it. He also gave a less freaky example of a fly with 4 wings. This is just my imagination, but imagine a human with 4 functional arms...they'll multi-task better, but I wonder how harsh his/her peers would be.

Alright, one more thing before I go. Last week (on Monday) I cut the head of a Planarian worm, with a razor, in between its eyes. I numbed it before I did it, I wasn't just doing it because I'm mean. It was part of the zoology lab.

With HOX genes it is supposed to regenerate two heads, with two eyes in each head. It's supposed to do that within a couple weeks. I checked on it Friday and there was another Planaria in there...but I think someone put theirs in my "dish" because it isn't supposed to multiply bodies, only the heads are supposed to multiply. Anyways, it was still alive on Friday. Hopefully it will be fine this Monday!

Answer 2

The question is not quite clear enough, Charles Darwin developed his theory of evolution, by deduction, by studying
finches on the different Galapagos islands.
He had very little to go by, very little fossil evidence
and absolutely nothing to shed light on human evolution.
But he drew the right conclusion.
If you mean science as a whole compared to science of today
read essays by Stephen Jay Gould, who was a Harvard professor
who lectured on the history of science.
There is lots of material whatever you need.
www.stephenjaygould.org

view the library.

Answer 3

First of all Charles Darwin had theories that he could not prove.Today scientist have more technologies at their disposal to test their hypothesis and then theories then fact.Also Charles Darwin could not separate his faith from his science.Today that is not a big problem..However science still has the same process we have just gotten better at it...good luck on your paper

Answer 4

Charles Darwin knew nothing of genes, so he did not have a mechanism of heredity. The blending process that he posited was dead wrong, as heredity is particulate in nature. He never was too comfortable with blending, but could think of no better method. That is one thing and I am sure others will have contributions.

Answer 5

I think the biggest difference is that we have the advantage of using DNA to establish relationships between species. Darwin had to go on observable characteristics - external and internal structural similarities.