Anthropology Hel

FYI… This is the problem with Intelligent

Design and its proponents. They

have no testable mechanism to

offer as evidence of its scientific

validity.

Introduction to Physical Anthropology ANTHRO 101 – ONLINE

Historical Influences Blog Post

Due Wednesday of Week 1 (Comments due Thursday)

Week 1 – Historical Influences on Darwin: BACKGROUND

The life’s work of Charles Darwin’s did not seek to provide evidence that evolution occurs. Even 160 years

ago, it was generally understood that organisms change over time. Scientists, however, were reluctant to

pursue this avenue of inquiry due to the social repercussions of the time, with the church frowning on any

ideas that seemed out of line with religious and biblical doctrine. Look at what the church did to Galileo

when he dared to argue that the sun was the center of our system of planets instead of Earth! Imagine the

pressure to avoid discussing the idea that organisms, including (and especially) humans, might evolve and

change.

Evolution is a natural process, observable in the world

around us. What was in question during Darwin’s time,

and what he sought to explain, was how evolution

happens, not if. Darwin’s hypothesis (now a theory), that

populations of organisms change over time in response to

environmental stress, provided a mechanism that

explained how this process of evolution worked. More

importantly, the mechanism of natural selection provided

a testable, falsifiable explanation that possessed powerful

predictive value, meaning that it allowed scientists to

predict what they expected to see in the natural world if natural selection really was the mechanism by

which evolution worked and then check to see if those predictions were true.

How does evolution work?

Here are some key points to remember regarding the logical argument

supporting Darwin’s theory of evolution by the mechanism of natural

selection:

 All organisms have the potential of reproducing exponentially. Two rabbits are roughly capable of

producing approximately 200 rabbits in their lifetime. Imagine if all 200 baby bunnies had 200

hundred more baby bunnies… and so on… and so on… That is exponential growth that has the

potential of having us up to our eyeballs in rabbits. But we aren’t up to our eyeballs in rabbits, are

we? Why not? This question is the starting point of Darwin’s work.

 What is preventing organisms from reproducing at their potential? Something is keeping those

rabbits from producing all those bunnies. Baby rabbits are costly to the parent to produce. The

parent needs time, shelter, food, water and protection from predators. These needs are called

“resources”.

 Resources are limited. Our planet has a limit of much it can hold and produce. There will not be

enough resources available for all organisms to reproduce as many offspring as they can.

 Organisms with better access to resources will be more successful in their reproductive efforts.

The rabbits with more food and water and shelter will reproduce more offspring than those rabbits

with fewer of these resources.

 Who gets better access to these limited resources? Is it random? Or are some organism better

“fit” to the environment, enabling them to compete more successfully for resources and avoid

predation better than others? Darwin hypothesized that organisms with traits that were better

adapted to their environment would have greater reproductive success because those traits allowed

them to be more competitive for the things they needed to reproduce.

 If the environment changes, the traits that are helpful or adaptive to that environment will be

different. Organisms with those new adaptive traits will have greater reproductive success than

others and those new beneficial traits will spread, producing a change in the population. This is the

process of natural selection, essentially the process of the natural environment selecting the

organisms that will be most successful.

 In order for natural selection to occur, reproduction MUST occur! Survival is not enough. If you

don’t pass on your traits, evolution will not occur.

 In order for traits to evolve and change, they MUST be heritable. This means they must be passed

on reliably from generation to generation through reproduction. This was actually a problem for

Darwin as he did not know how traits were passed on. The current thinking of that time argued for

Fluid or Blending Inheritance, which actually blends out traits. We will meet someone next week

who helped solve this problem.

 Individuals do not evolve. Populations do. Individuals cannot change their heritable traits; they

can only pass them on. Evolution does not occur within a generation. It occurs between

generations.

 Artificial selection is identical to natural selection with one important difference. The selective

force in artificial selection is not the environment, but instead humans choosing which organisms

successfully reproduce and which ones don’t.

Blog Post Instructions (50 points):

Science is never completed in a vacuum. All scientists are working in their current scientific environment,

filled with the ideas and explanations of the day. Here is a brief (and incomplete) list of contemporary

individuals whose work and contributions influenced and shaped Darwin’s work.

Jean-Baptiste Lamark

Georges Cuvier

Charles Lyell

Thomas Malthus

Alfred Russel Wallace

Create a new blog post that accomplishes the following (Due Wednesday by 11:59 pm)

1. Select one of the five individuals listed above who you would argue had the most influence over

Darwin’s development of his theory of Natural selection. This could be a positive or a negative

influence.

2. Briefly (but completely) describe the contribution this individual made to the scientific community.

You must provide one link to an online source of information besides your textbook. No Wikipedia

sources! ( 10 pts)

3. From the bullet point list above (under “How does evolution work?”), identify the point (or points)

most directly affected by this individual’s work and thoroughly explain how this point was

influenced by your selected individual. Again, this could be a positive effect, meaning Darwin built

upon the knowledge this information provided, or a negative effect, meaning that Darwin

demonstrated that this individual’s idea(s) were incorrect and the mechanism of natural selection

was an alternative explanation. (10 pts)

4. Could Darwin have developed his theory of natural selection without the influence and ideas of this

individual? Explain. (10 pts)

5. How did the attitude of the church affect Darwin and his eventual publication of his book On the

Origin of Species? (10 pts)

Make at least two significant, constructive responses to blog posts of your fellow students, provided

positive and/or constructive feedback. (Due Thursday by 11:59 pm – 5 pts each)

Grading Matrix for Blog Post & Responses

Poor Average Excellent

Post No post is made prior to

the due date. (0 pts)

Post is made prior to the due date that

satisfies some of the criteria OR post is made

after due date that satisfies all criteria.

(20 pts)

Post is made prior to the due date that

satisfies all criteria. (40 pts)

Responses No responses are made prior to the due date.

(0 pts)

One response is made prior to the due date or

two responses are made by the due date

that fail to demonstrate effort or thoughtful

feedback. (5 pts)

Two responses are made prior to due date that demonstrate effort

and thoughtful feedback. (10 pts)