Evidence for Evolution

I think that it is important to be able to explain  that scientists do not support evolution because they are anti-religious but rather because the theory of evolution helps us to understand every facet of biology. Here is a link to a powerpoint presentation that outlines some of the strongest lines of evidence in support of evolution.

http://www.slideshare.net/secret/yZbDE8FNSCzKFS

Creationism and Intelligent Design

Note: This material will not be included on the final exam.  I have included it in case you are interested in learning more about the topic.

We are now reaching what is usually the most difficult part of this course- talking about evolution. Because Lubbock is located near the buckle of the Bible Belt, this topic is always controversial with my students here at Tech.  Obviously, the teaching of evolution in Texas schools continues to be controversial and it remains to be seen what the revised TEKS will be like. Because my understanding of the process of evolution is the most powerful tool that I have in my biological toolbag I think it is critical that you learn why I think that evolution is such a powerful tool for helping us to learn about biology. My goal is not to be controversial or step on anyone's toes and I hope that we will be able to have good discussions about this topic.

Creationism and Intelligent Design

In his book “Tower of Babel The Evidence Against the New Creationism”, Robert Pennock reviews the various types of Creationists.

“Wild-type” Creationist

God dictated the bible word for word so we must take it literally. From Genesis we know (i)God created the world from nothing in 6 days, 6000 years ago and (ii) God destroyed the world with a great flood, all current people and animals are descendents of Noah’s Arc.

There are different views of Creationism today which arises out of biblical interpretation

Most creationists consider themselves as Evangelicals
- Biblical inerrancy- can be understood in different ways
- Bible is the revealed word of God- so every word is true
- plenary verbal inspiration- Biblical writers directed by God but used own style
- inspired concepts- written down by people over time

Young Earth Creationism

Bible is meant to be taken literally on all matters of faith and the real world

-creation took 6 24 hour days
-Adam formed directly from the dust on the ground and Eve from Adam’s rib
- Jonah was literally swallowed and lived in the Belly by as great fish

1- sudden creation of the universe, energy, and life out of nothing
2- the insufficiency of mutation and natural selection in bringing about the development of all living kinds from a single organism
3- changes only within fixed limits of originally created species
4- separate ancestry of humans and apes
5- explanation of earths geology by catastrophism including a worldwide flood
6- A relatively recent inception of earth and living kinds

Dated by readings of ancestry in the Bible- 6000 to 10,000 years

Young Earth Creationists include-
1)Institute for Creation Research- San Diego - Duane Gish, Henry Morris and his son
2)Answers in Geneis- Kentucky-Ken Ham and Gary Parker
3)Center for Scientific Creationism- Phoenix

Old Earth Creationism

-still consider biblical inerrancy, just don’t read the bible literally

Days are not 24 hour human days, but are God-sized days
Others apply gap interpretation- gaps between Genesis 1:1 and 1:2
Days are “actual days” but they are not consecutive

There is a big battle between the Young Earth Creationists and the Old Earth Creationists

Progressive Creationism

Accepts much of the scientific picture of development of the universe, assuming for the most part that it developed according to natural laws.
- God intervened at strategic points along the way

Theistic Evolutionism

Theists who accept Darwinian evolution. Basically view God as a creator- started physical laws etc.

Evolutionary creationism

God directly guided the process of evolution

Intelligent-Design Creationism

Many ID proponents hold advanced degrees and positions in universities

Phillip Johnson- UC Berkely Law school
Michael Behe- Biochemist,Lehigh University Biology Department

Johnson’s view
1. personal creator
2. supernatural
3. initiated
4. continues to control the process of creation
5. in the furtherance of some end or purpose

“irreducible complexity”- some systems are complex and can only work if the entire system is in place
-therefore there is no way that they could be formed by gradual steps because there is no way that earlier versions could have been selected for

Interesting idea, but again I don’t see that it is science (even worse it doesn’t help us get anywhere- can’t make any predictions or lead to new avenues of study)

Is there a controversy between evolution and creationism?

1) Scientific controversy?

No- evolution remains the cornerstone upon which everything in biology makes sense. No “real biologist” that I know thinks that there is a problem. I know of no creation scientists or ID proponents that do not admit to being Christian and that that is a important part of why they feel as they do (I at least respect that most of these ID scientist are up front about their religious beliefs)

Theistic science- “The Bible is the ultimate scientific approach” This approach would fundamentally change the way that we approach science and the scientific community has certainly not seen the need for this.

2) Religious controversy?

The debate is often framed as being between scientists and fundamental creationists
-not necessarily the case because many mainstream Christian denominations have no trouble with evolution

-thus there may be a religious controversy between different Christian beliefs

3) Philosophical controversy?
Evolution/creation debate often linked to Gallileo and Church debate

Battle between the truth of nature and the nature of truth

Creationists have tried to use ID as a wedge to show that people are either for the religious position or against it- there is no middle ground.
-The Bible is either inerrant or worthless
-Christianity or atheism
-Certainty or sketpticism
-Absolute morality or subjectivism (relativism)

Many philosophers would argue that these issues are not so black or white.

4) Political controversy?

Controversy is a struggle for power
- whichever side gets the most votes should be the side that wins
- science be damned??

Brief History of Creationism

Modern History began with the Scopes “Monkey Trial” in 1925. The ACLU orchestrated a challenge of the Tenessee state law that banned the teaching of evolution. The trial was one of the first famous trials fought in the media featuring Clarence Darrow vs William Jennings Bryan. Bryan thought that American society was undergoing moral decay that he blamed on scientific materialism as exemplified by evolution were making people question biblical authority.

Even though Bryan officially won his case (Scopes was fined $100) the general public generally agreed that evolution had won (Bryan tried to defend the Genesis version of creation on the stand and was torn apart by Darrow).

Textbook publishers were uninterested in controversy so they basically excluded evolution from biology books up until the end of the 1950s.

In the 60s the sputnik scare revitalized American Science teaching – BSCS curriculum contained evolution.

In 1973 Tenesee passed a law saying that anyone who taught evolution also had to teach the Genesis account. In 1975 this law was found unconstitutional because it was blatantly including religion

Over the next several years creationists passed laws in several states requiring the teaching of “creation science”

1982 case in Arkansas challenged a law requiring the teaching of creation science. The case brought in experts on evolution, thermodynamics and geology also experts on religion to answer the question-was creation science really science?

Judge Overton defined science as “what scientists do” and “what is accepted by the scientific community”. He dentified the “essential characteristics” of science (based on the ideals of the philosopher of science Michael Ruse)

1. It is guided by natural law
2. It has to be explanatory by reference to natural law
3. It is testable against the empirical world
4. Its conclusions are tentative; i.e., the are not necessarily the final word
5. It is falsifiable

Overton ruled that creation science fails to meet the essential characteristics and was thus not science.  From religious testimony he ruled that creation science was religious so the law violated the establishment clause.

2004 Georgia case

Required placement of sticker on biology books as “a theory not a fact”
Judge ordered the stickers removed

2004 ID case- Dover Pennsylvania

The policy required students to hear a statement about intelligent design before ninth-grade lessons on evolution. The statement said Darwin’s theory is “not a fact” and has inexplicable “gaps.” It referred students to an intelligent-design textbook, “Of Pandas and People.” (which turns out to be a creationist book that basically had the words “creation” replaced by the words “intelligent design”.)
Judge Jones, a Republican and a churchgoer appointed to the federal bench three years ago. decried the “breathtaking inanity” of the Dover policy and accused several board members of lying to conceal their true motive, which he said was to promote religion. A six-week trial over the issue yielded “overwhelming evidence” establishing that intelligent design “is a religious view, a mere re-labeling of creationism, and not a scientific theory”

ID “may be true, a proposition on which the court takes no position, ID is not science.” Among other things, he said intelligent design “violates the centuries-old ground rules of science by invoking and permitting supernatural causation”; it relies on “flawed and illogical” arguments; and its attacks on evolution “have been refuted by the scientific community.”

How do Creationists and proponents of Intelligent design attempt to attack evolution?

The IDers (and other creationists) often take these approaches to get their message across

1) Try to refute evolution
Set up a false dichotomy that there are two possible explanations for the origin of the life either by evolution or created by the Judeo-Christian God. They try to show weaknesses in evolution and then having shown that evolution is wrong we are forced to accept their view of creationism. However, here are many other possible creation stories than Genesis.

2) Equal time approaches
There are two valid scientific alternatives so it is only fair to present both ideas. This doesn’t work for two reasons- (i) there are not only two alternative (Australian aboriginals and Mayans have their own creation stories)and (ii) hese other approaches are not science because they inherently bring in a supernatural creator.

3) Force of Numbers

IDers from the Discovery Instute presented a petition showing that 400 scientists dissented from Darwinism- took them 4 years to get this many signatures. 128 signees were Biologists and virtually none of them conducted research that had anything to do with the subject (the one signatory I know from Tech is an Electrical Engineer).

Some scientists responded with The Four Day Petition, whose name A Scientific Support For Darwinism is an allegorical reference to the Discovery Institute's A Scientific Dissent From Darwinism, a petition that took four years to generate just over 400 signatories. This project, The Four Day Petition, ran from Sept 28th , 2005 to October 1st , 2005. R. Joe organized the Four Day Petition with no outside funding or professional society’s assistance and generated 7,732 verified signatories of concerned scientists, all by word of mouth (well e-mail actually). Of those signatories 6,965 are US residents including 4066 with a PhD.
“My genuine thanks to the thousands of you who felt strongly enough about this petitions statement to make the time during those four days to pass the word onto your personal network of peers. The response to your efforts was tremendous. Your efforts resulted in a response 1809% higher than the Discovery Institutes at a rate 697,000% faster. It is also interesting to note that the Discovery Institute budget is $4,000,000 a year while mine is, well non existent J These results are not bad my friends, not bad at all.”

4) Because Creationists have repeatedly had their ideas judged to be a religious they have tried to argue that evolution is really a “secular religion”

5) The Kansas Board of Education has taken a couple of clever strategies. They eliminated evolution from the state science standards. Teachers remain free to teach it, but won’t be tested on it which basically eliminates it from the curriculum. When in 1999, the board eliminated most references to evolution, a move Harvard paleontologist Stephen Jay Gould said was akin to teaching "American history without Lincoln."

The Kansas School Board then tried a new approach and rewrote the definition of science, so that it is no longer limited to the search for natural explanations of phenomena.

No wonder - "The 10 Worst Jobs in Science," as listed by Popular Science magazine, October 2005: #3 is Biology teacher in Kansas

Interesting New Articles About Human Population Growth

Population Controls Will Not Solve Environmental Issues. BBC. Oct. 27, 2014

http://www.bbc.com/news/science-environment-29788754


It's Not A Small World Afterall: World Population Will Soar

http://www.bbc.com/news/science-environment-29788754


World Population Stabilization Unlikely This Century. Science October 2014

http://www.sciencemag.org/content/346/6206/234.abstract

Human Population Growth

I have spent a lot of time trying to convince you that exponential growth is an unrealistic model of population growth. Interestingly, human populations have experienced exponential-like growth. How can this be?

What makes humans different from other species?

In other species per capita birth rates and per capita deaths rates are density dependent. However, as human populations have increased there has been no corresponding decline in per capita birth rates or increase in per capita death rates. What makes humans different from other species?

Humans have the ability to alter their environment so that they can avoid the density dependent effects on birth and death rates. 1) Humans have increased food production by improvements in agriculture (e.g., irrigation, fertilization, mechanized farming, genetically improved crops). 2) Humans have been able to decrease death rates by improvements in medicine and public health (things as simple as not pooping in the water you drink helps a lot!). 3) Humans have elimnated most human predators (ocassionally, someone gets killed by a shark or a mountain lion).

Where is human population growth occuring?

The rates of human population growth are not the same in all regions. Today, human populations are increasing in size much faster in developing countries (e.g., Mexico, other countries in Central America, Africa, and Southeast Asia) than they are in developed countries (e.g, USA, Canda, Western Europe). The figure at the top of this post shows the patterns of population growth in developed and developing nations.

Thus we see that populations are increasing most rapidly in the countries that are least able to deal with a rapidly increasing population. See "Population Challenges-The Basics" that can be downloaded from the Population Institute's website.
http://www.populationinstitute.org/population-issues/index.php

Human Population Growth Problem?

There is a great deal of debate about whether increasing human populations are a problem or not, and if they are what should be done about it. Unfortunately, we don't have time to discuss this issue in very much detail in class. My personal opinion is that we have too many people consuming too many resources and the last thing that we need are billions more people living on the planet. This is an issue that I am always intersted in talking more about if you would like to chat.

Further Reading

The section on Human Population Growth in your textbook is quite good.

Also see the article "Human Population Explosion" from the EoE.
http://www.eoearth.org/article/Human_population_explosion

Both of these contain a good discussion of the "demographic transition".

Really Cool Video

Here is a link to a YouTube video on "World Population" The first minute and a half or so is a little boring, so you can skip over it if you wish. However, I think the animation showing when and where human population growth has been occuring is really cool.

http://www.youtube.com/watch?v=4BbkQiQyaYc

Powerpoint Presentation

http://www.slideshare.net/MarkMcGinley/human-population-growth-16369173

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- describe patterns of human population growth in developed and developing nations

- discuss some reasons why the pattern of population growth in humans is so different from that in other species

- describe the demographic transition

- discuss their own personal view of human population growth.

Writing Assignment #3

We need to start by having a conversation about climate change. It would be irresponsible to avoid the issue just because it's uncomfortable to talk about.

Al Franken

I would like you to start a conversation about climate change with one of your fellow TTU students.  Identify your audience (you don't need to identify them by name, but identify the important characteristics of this person that will influence how you direct your conversation).

3 pages maximum, double spaced, Times New Roman 12 point font (if you include references you may add an additional page for references)

First Draft Due- Wednesday November 12th

Writing Workshop-  Friday November 14th

Final Draft Due- Monday November 24th

Population Ecology III: Logistic Growth

We are trying to develop a mathematical model that helps us to understand patterns of population growth. So far our first attempt, the exponential growth model, did not help us to understand population growth (for reasons that I hope that you understand by now).

The "Real" world

In our attempt to think about population growth in the real world, we attempted to examine how per capita birth rates and per capita death rates should vary as population size varies. The model that describes this pattern of growth is known as the logistic growth model. It is important to realize that although this model is much more realistic, and therefore useful to us, than the exponential growth model, the logistic growth model still only examines what I call "the theoretical real world". That is, this model applies to our ideas about how populations should generally behave and do not thus relate directly to studying the population sizes of white tailed deer in central Texas or parrot fish on a coral reef in Fiji.

Logistic Growth

We have discussed why, in the real world, r should decrease as population sizes increase. If this is the case then there is a population size at which the per capita birth rate equals the per capita death rate. We call this population size the carrying capacity.

1) When populations are smaller than the carrying capacity we expect them to increase in size until they reach the carrying capacity.

2) When populations are larger than carrying capacity we expect them to decrease in size until they reach the carrying capacity.

3) When the population size equals the carrying capacity we expect no change in the size of the population.

The logistic growth equation is a mathematical equation developed by biologists to describe patterns of population growth consistent with the ideas above. Before focusing on the biological insights that we can gain from the logistic growth model (the real purpose of everything we have been doing) it is important to really understand patterns of logistic growth. Hopefully, this powerpoint presentation will help you understand these patterns better.

Powerpoint Presentation

Click here for a powerpoint presentation entitled "Fun With Graphs- Logistic Growth"

http://www.slideshare.net/secret/gyB3cjnSplLw41

NOTE: THERE IS AN ERROR ON SLIDE 16 OF THIS PRESENTATION!!!

The title of the graph on slide 16 should read "Logistic Growth: dN/dt vs t (Not N), N initially << k"

The x-axis of the graph is TIME (please ignore the values of K on the x-axis because K does not belong on the time axis). The shape of the graph is correct. Make sure you change the x-axis to Time rather than Population Size.

Expected Learning Outcomes

By the end of this course a fully engaged students should be able to

- define the carrying capacity

- draw, and interpret the following graphs associated with logistic growth
a) how population size changes over time in logistic growth when the initial population size is much smaller than the carrying capacity

- discuss the causes for the shape of the s-curve (this answer will need to include a discussion of both math and biology)

- discuss the factors that regulate population size, be able to distinguish between density dependent

Population Ecology II: Exponential Growth

From the first lesson on Population Ecology we learned that the population growth rate (dN/dt) can be calculated as the product of the per capita growth rate (r) and the population size (N).

dN/dt = rN

This is the fundamental equation describing population growth and this equation is always true.

If we want to use this equation to analyze how population sizes change over time, then it makes sense to start by examining the simplest formulation of this equation which occurs when the per capita growth rate is constant. The equation dN/dt = rN when r is constant is known as the exponential growth equation and this equation describes a patter on growth known as exponential growth.

The graph plotting how population size changes over time is shown in the Exponential Growth article. This graph shows an exponential growth curve (sometimes known as the "j-curve"). If you have questions about why the graph has this shape let me know and I will try to explain it more thoroughly.

It is important that you are able to look at this graph and determine all of the information held in the graph. The exponential growth curve allows us to discuss how two parameters change over time- 1) the population size (shown by the x-axis) and 2) the population growth rate (shown by the slope of the line). I find that it is easier to discuss only one parameter at a time so let's start with the population size.

1) Over time, the population size increases (we know this because the line has a positive slope).

Now let's think about the population growth rate.

2) Over time, the population growth rate increases (we know this because the line gets steeper over time.

3) Over time, the rate at which the population growth rate increases over time, increases over time (we know this because the slope increases faster and faster over time).

Thus, if populations are growing exponentially then they keep increasing in size at an ever faster rate forever and ever.

Exponential Growth is Unrealistic
Because population sizes keep increasing at ever faster rates for ever, exponential growth does not seem to be an accurate description of population growth in most animals, plants, and microbes. If this is an unrealistic model then why did I teach it to you? I started with exponential growth becasue it is the simplest model of population growth and scientists always like to describe the world using the simplest models that they can.

Obviously, in this case we have started with a model that is too simple to realistically describe the world. What is wrong with the exponential growth model? The fundamental assumption we made about exponential growth is that the per capita growth rate is constant. This must not be a realistic assumption.

It is important that you understand, and are able to explain, both the mathematical reasons and biological reasons that exponential growth is an unreasonable model of population growth. I tried to explain biologically why exponential growth is unrealistic in the "Exponential Growth" article and the attached Powerpoint presentation so take a look at those.

Suggested Readings

Here are some articles you should look at from the Encyclopedia of the Earth. I wrote these so they are brilliant!!!

Population Ecology http://www.eoearth.org/article/Population_ecology

Exponential Growth http://www.eoearth.org/article/Exponential_growth

Logistic Growth http://www.eoearth.org/article/Logistic_growth

Carrying Capacity http://www.eoearth.org/article/Carrying_capacity

Intraspecific Competition http://www.eoearth.org/article/Intraspecific_competition

Powerpoint Presentation

Click here for the Powerpoint presentation "Why is Exponential Growth Unrealistic?"
http://www.slideshare.net/secret/IDPugQtl2wvONv

Expected Learning Outcomes

By the end of this course a fully engaged student should be able to

- draw and interpret the graph that shows how population size change over time in exponential growth

- explain why exponential growth is an unrealistic pattern of growth for most species

- define and explain the carrying capacity

Population Biology I: Basic Parameters

Expected Learning Outcomes

By the end of this course, a fully engaged student should be able to

- define b, d, r, B, D, dN/dt.

- identify and use the proper units associated with each parameter

- use the correct algebraic equations to calculate each of these parameters

- be equally comfortable referring to these concepts verbally or via their algebraic symbols.

Basic Parameters of Population Ecology

Here is a brief introduction to some of the important parameters that we will need to understand to be able to study population ecology. For each of the parameters it is important that you know (1) the name of the parameter, (2) the algebraic symbol used to represent the parameter, (3) the units of measurement for the parameter, (4) how to calculate the parameter, and (5) how to describe (in words) what a particular value of that parameter means.

It is probably easiest for me to introduce these concepts using an example.
Imagine that in a population of 100 elephants that in one year 10 elephants are born and 5 elephants die.

1) Population Size (N) units- individuals. Measures the number of individuals in a population.

N = 100 individuals

In this population of elephants, there are 100 individuals.

2) Population Birth Rate (B) units- number of births per time. Measures the number of births per time that occur in a population.

B = 10 births/year

In this population, each year there are 10 births.

3) Population Death Rate (D) units- number of deaths per time. Measures the number of deaths per time that occur in a population.

D = 5 deaths/year

In this population, each year there are 5 deaths.

4) Population Growth Rate (dN/dt) units- number of idividuals per time. Measures the rate of change of the population size.

dN/dt = B - D

dN/dt = 10 births/year - 5 deaths/year = 5 individuals/year

In this population, the population size increases by 5 individuals each year.

5) Per Capita Birth Rate (b) units- births per time per individual. Measures the number of births per time averaged across all members of the population.

b = B/N

b = (10 births/year)/100 individuals = 0.10 births/year/individual

In this population, each year 0.10 babies are born for each individual in the population.

6) Per Capita Death Rate (d) units - deaths per time per individual. Measures the number of deaths per time averaged across all members of the population.

d = D/N

d = (5 deaths/year)/100 individuals = 0.05 deaths/year/individual

In this population, each year 0.005 individuals die for each individual in the population.

7) Per Capita Growth Rate (r) units = individuals/time/individual. Measure the rate of change in population size averaged across all individuals. The per capita growth rate can be calcuated two ways.

a) r = b - d

r = 0.10 births/year/individual - 0.05 deaths/year/individual = 0.05 ind/year/ind

b) r = (dN/dt)/N

r = (5 individuals/year)/100 individuals = 0.05 individuals/year/individual

In this population, each year 0.05 individuals are added for each individual in the population.

Practice Problem

1. In a population of 50 tigers, in one year 10 tigers are born and 20 tigers die. What is B, D, dN/dt, b, d, r?