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Web Links

Please note that some of the weblinks below are directed toward content provided by the Canadian Broadcasting Corporation (CBC). Due to labour disruptions, some of these CBC weblinks are currently not accessible.

Chapter 6 Evolution

Section 6.1 Evidence of a Changing Earth

Page 86

Did You Know: Visit the Royal Tyrrell Museum
The Royal Tyrrell Museum opened in 1985, commemorating Joseph Burr Tyrell, the man credited with finding the first dinosaur fossils in the Drumheller Valley, Alberta, in 1884. You can view the museum's fabulous fossil collection or find out about it's many active programs in person or online.

The Royal Tyrrell Museum
The home site of the Tyrrell Museum including information on their programs, what's new in the field, finding fossils, and the people behind the science at the museum.

Page 86

Web Activity: Finding Fossils and Famous Footprints
In 1976, some famous fossils dating from more than 3.6 million years ago were discovered in Tanzania. They represented some of the oldest fossil evidence for upright, bipedal, walking - a milestone in human evolution. Find out more about these fossils and be introduced to Lucy!

How Did Humans Evolve? Is Evolution Still Happening?
Online lessons on how humans have evolved, and still are evolving.

Becoming a Fossil & Laetoli Footprints
PBS web site contains information and video on the finding of Lucy.

Page 87

Section 6.1 Questions
4. Research carbon 14 ( 14 C) dating techniques, including why the percentage of 14 C begins to change after an organism dies. Report your finding to your class.

Carbon 14 Dating
An explanation of how Carbon 14 dating works, and how it is used to date fossils.

Section 6.2 Evidence of Evolution from Biology

Page 89

Mini Investigation: Variations on a Theme

The forelimbs of different vertebrates are well adapted to serve specific functions. However, hypothesizing the potential adaptive advantages of such homologous features are not always easy. Explore the bill shapes of six different bird species. Choose four species that are living and two that are extinct.

Bird Characteristics
This site contains details and photos of the characteristics of many birds, including: toucans, pelicans, falcons, and hummingbirds.

The Aviary
The Aviary contains information on all extant species in alphabetical order.

Extinct Bird Species
This site contains information on and images of prehistoric and extinct animals, including: the Dodo, Gastornis, and Diatryma.

Page 93

Web Activity: Were Neanderthals Humans?

For many years, paleontologists disagreed over the classification of Neanderthal. Although they were shorter and heavier than modern humans, their fossil remains are very similar to other recent hominids that have been classified as archaic H. sapiens . Many paleontologists suggested Neanderthal, be classified as a subspecies of humans (i.e., as H. sapiens neanderthalensis ), while others concluded they should be placed in a separate species (i.e., as H. neanderthalensis ). Fossil evidence does not provide much information concerning mating patterns and other reproductive isolating mechanisms between very similar populations. However, in the late 1990s, several different samples of mitochondrial DNA were actually extracted from well-preserved Neanderthal fossils, amplified, using polymerase chain reaction, and sequenced.

. Compare an actual Neanderthal mtDNA sequence to that of modern humans.

(a) How does the mitochondrial DNA of humans compare with chimpanzees?

(b) How many base-pair differences are typically found between the mtDNA of any two distantly related people?

(c) How many base pairs could be sequenced in the Neanderthal mtDNA?

(d) How many differences were detected between the Neanderthal sequence and that of a modern human?
(e) Does this DNA evidence suggest that Neanderthal are archaic members of the modern human species or members of a different species? Explain.

Mitochondrial Control Region
Mitochondrial Control Region is a fantastic genetic site, all about mtDNA. The 'Theory' section explains the origins and function of mtDNA, its role in disease, and its applicability to science. The 'Media' section contains an animated essay that tells the story of Solving the Neanderthal Mystery. Clicking on the arrow at the bottom of the first screen in the 'Exercises' section leads to step-by-step instructions on how to access, compare, and interpret real sequence data contained within the site.

Fossil Hominids: Mitochondrial DNA
Fossil Hominids: Mitochondrial DNA is a balanced, matter-of-fact essay on the mtDNA research that has been done on fossil hominids, particularly Neanderthals. Comparisons with humans and chimps are made, and the implications of the results discussed in simple terms. A list of links, mainly to news reports on the mtDNA research, is given at the bottom of the page.

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6. New Zealand scientist David Lambert collected DNA samples from 7000-year-old nesting grounds of the Adelie penguin in Antarctica. He collected wonderfully preserved DNA samples from ancient frozen bones in layers of ice directly beneath the present day nesting colonies. What does Lambert's evidence suggest about the rate of evolutionary change in this species of penguin?

Ancient Penguins Yield Evolution Clue
This BBC News article discusses the DNA clues left by the Adelie Penguins discovered by David Lamberts. Genetic mutation, which occurs at a steady rate, can be calibrated by looking at the difference in DNA from two different lineages of Adelie penguins.

History and Evolutionary Biology
This article, from the Society of Molecular Biology and Evolution, explains that David Lamberts' study of the Adelie penguins lineage through DNA allows us to estimate evolutionary rates, and therefore, more accurately calculate the timing of divergent events in history.

Section 6.3 The Making of a Theory-Accounting for the Evidence

Page 96

Web Activity: Simulating Natural Selection-Evolution in Action
The role of environmental change presents scientists with opportunities for investigation of variations in species in affecting population change. A well-known real-world case is that of the peppered moth ( Biston betularia ). In England in the early 1800s, light-coloured lichen covered many surfaces, providing camouflage for light-coloured forms of the peppered moth. But the growing Industrial Revolution changed the English countryside in many ways; the production of pollutants blanketed some areas in soot, which offered new opportunities for some species to camouflage themselves from predators.

In 1848, near Manchester, the first appearance of a melanic (almost black) form of peppered moth was recorded. By the late 1800s, much of the lichen was dead and the trees, rocks, and other hard surfaces were covered in dark soot. By the 1920s, the moth population was almost entirely of melanic individuals. Scientists suspected that the melanic moths had gained a selective advantage.

Biologist H.B.D. Kettlewell formed and tested a hypothesis that the observed evolutionary change in the colouration of the peppered moth throughout the 1800s was a result of changes in the environment ( Figure 1 ).

Figure 1

Biologist Laurence Cook has reported that, since 1975, the prevalence of melanic moths around Manchester has decreased significantly and lighter coloured moths are making a dramatic comeback. Tree bark is becoming lighter again; however, during the study, lighter-coloured lichens that supposedly camouflage the moths did not seem to be more common and the moths were seldom seen on trees.

Follow the links below to animations that model how environmental changes can affect individuals of a species of various colours. Think about how this model supports or refutes Kettlewell's theory.

Evolution in Action
An interactive feature shows how random mutations can lead to species-wide change.

Evolution Lab
An interactive simulation animating the natural selection process.

Page 96

Did You Know: Darwin's Writings
On his voyage, Darwin lavished attention on coral reefs. In 1842, he published his theories on their formation, and these are still accepted today. Darwin wrote about his travels in The Voyage of the Beagle, which can be read in print or online.

Darwin's Voyage of the Beagle
The on-line library has a posting of The Voyage of the Beagle by Charles Darwin.

Alternate Source
This site also contains a posting of The Voyage of the Beagle.

Section 6.4 Sources of Inherited Variation

Page 102

Section 6.4 Questions

7. Some prions that cause diseases such as bovine spongiform encephalopathy (mad-cow disease) and the inherited form of human spongiform encephalopathy ( Creudtzfeldt-Jacob disease) result from single genetic mutations. Research the genetics of these diseases and explain how they are transmitted. Suggest why they are not eliminated by natural selection.

What is BSE?
This Canadian Food Inspection Agency site explains what BSE is, symptoms of BSE, and how it is treated.

Mad Cow: Science and Symptoms

This CBC News article explains Mad Cow disease, how it is transmitted, as well as explaining the significance of prion disease identification.

8. Research Richard Dawkin's theory about "selfish genes." Prepare arguments for a class debate on his theory.

The Selfish Gene
This site explains Richard Dawkins' theory of the Selfish Gene, whereby gene selection is at the center of evolution.

Gene Juggling
In this article, from the Royal Institute of Philosophy, the author, Mary Midgley contradicts Dawkins' view from The Selfish Gene.

In Defence of Selfish Genes
In this article, from the Royal Institute of Philosophy, Dawkins defends his position on the Selfish Gene and directly opposes Mary Midgley's assault.

Section 6.5 Speciation and Evolution

Page 104

Web Activity: Testing a Theory-Lactose Intolerance and Evolution
Lactose is a disaccharide found in mammalian milk. The digestive enzyme lactase (a-galactosidase), produced by cells lining the small intestine, hydrolyzes the disaccharide lactose into glucose and galactose. In most mammals, the ability to digest lactose is lost in adults. In humans, lactase production usually begins to decrease after about the age of two years. This inability to produce high amounts of lactase results in the common condition known as lactose intolerance. In January 2002, Dr. Leena Peltonen of the University of California and Nabil Sabri Enattah of the University of Helsinki, Finland, reported the discovery of a gene responsible for lactose intolerance. This discovery has shed new light on the evolution, potential diagnosis, and treatment of this condition.

People with lactose intolerance may suffer from nausea, cramps, gas, and diarrhea after consuming foods-dairy products, in particular-that contain lactose. The severity of symptoms varies from individual to individual and depends, in part, on the amount of lactose ingested.

For this task, you and two other students will investigate lactose intolerance and tolerance. Review the components of this task and decide as a team which of you will complete which one of the two parts (I or II). Each member is responsible for completing and submitting his or her assigned task, along with a report that includes responses to the Analysis questions. Each team member should be familiar with all the other members' reports. Present your survey and other plans for your procedures to your teacher for approval before carrying them out. Following completion of the procedure and analysis, you will be asked to review one of your team member's reports, and you will submit your report to a team member for peer review.


As a team, find answers to the following questions:

(a) What is the incidence of lactose intolerance in human populations?

(b) What gene(s) are responsible for the regulation and production of the lactase enzyme?

(c) What role has natural selection and mutation played in the evolution and prevalence of lactose tolerance and intolerance?

(d) What technology and methods are currently used to diagnose, avoid, and or manage lactose intolerance?
(e) How might new advances in technology and in knowledge about lactose intolerance be used to improve its diagnosis and treatment?

Part I: The Genetics and Prevalence of Lactose Tolerance and Intolerance

1. In this investigation, your goal is to obtain a crude lower estimate of the incidence of lactose intolerance in your school or community. Conduct a survey of at least 40 students and/or adults in your school or community.

2. After completing your survey, generate some hypotheses regarding the incidence of lactose intolerance in the total population of surveyed participants.
3. Use print and electronic sources to determine what gene or genes are responsible for the production of lactase, and find out the occurrence of lactose tolerance and intolerance in human populations of the world.

(f) Does lactose intolerance result from a mutation in the gene that codes for the lactase enzyme? Is this surprising? Explain.

Part II: Natural Selection and Lactose Intolerance
4. Most adult mammals do not produce the enzyme lactase. Apply your understanding of evolution and natural selection to develop and test hypotheses about this trait. Research print and electronic sources to find supporting evidence for your hypotheses and conclusions.

Lactose Intolerance is Normal!
Lactose Intolerance is Normal! reads the headline of this article from the Science in Africa Web site. The evolution of lactose tolerance is discussed, and its global prevalence detailed.

Lactose Intolerance
Lactose Intolerance: this Web page from the U.S. National Institute of Health provides general information about its symptoms and treatment.

When Milk Makes You Sick
When Milk Makes You Sick, a report by a university student from Indiana University , provides an excellent summary of lactose tolerance, its chemistry, genetics, and evolution.

Lactose.Net provides a list of links about lactose. Some sites are good sources of general information, while others are mainly about selling products or providing recipes.


(g) What might be the selective advantages of not producing lactase as an adult?

(h) Other than humans, would adult mammals ever suffer from the symptoms of lactose intolerance? Explain.

(i) Would you expect lactose intolerance to be an ancestral or a derived condition? Explain.

(j) What change in the environment and/or human behaviour would create a selective advantage for those individuals who continued to produce lactase as adults?

(k) When and where did humans begin to domesticate cattle, camels, and goats? When and where did humans begin using milk as a source of animal protein? How is this information significant?
(l) Based on this data and evidence collected in Part I, does natural selection appear to have played a role in the evolution of lactose tolerance in humans?

Part III: Options and Opportunities in the Control and Treatment of Lactose Intolerance
5. Human societies have been consuming milk and milk products from large domesticated mammals for thousands of years. When this practice began, humans would not have had the gene for lactose tolerance. Research in print and electronic sources the technologies that have and could be applied to treat lactose intolerance.

Planet Lactose
Planet Lactose is a one-stop information center on lactose intolerance.
The 'Research' section has articles in easy-to-understand language that explain the latest scientific advances, with an archive of past news stories.

Gene Therapy in a Liquid
ScienceDaily online magazine reports that Gene Therapy in a Liquid has been administered to some rats by Thomas Jefferson University professors. The result? They cured the rats' lactose intolerance. The research has exciting implications for other medical conditions, like diabetes.


(m) What products have humans used as alternatives to milk to avoid or reduce the incidence of lactose intolerance? Explain how the lactose is removed or reduced in these products.

(n) What is Lactaid? Design and conduct a simple experiment to demonstrate how this product functions. Explain how people with lactose intolerance could use the product.

(o) How might recent discoveries in genetics be used to develop new diagnostic tools for detecting lactose intolerance?
(p) Investigate and report on past research and potential new developments in the areas of lactose intolerance. Could lactose-free cows be genetically engineered? Could lactose-intolerant individuals undergo gene therapy?

Page 107

Section 6.5 Questions
6. Evolutionists have concluded that mammals have evolved from a group of reptiles. Based on your understanding of fossil formation and evolution, make a testable prediction about the fossil records of mammals and reptiles. Conduct literature and internet research to see if your prediction was valid.

Examples of Evolution
This site discusses the fossil record evidence of the evolution of vertebrate legs, the evolution of birds, and the evolution of mammals.

Mammal Evolution
This site describes the fossil record timeline, by which reptiles are thought to have evolved into mammals.

Evolutionary Biology
This site looks at evolutionary biology as prescribed by Darwin's theory. The theory of separate creation is also explored, whereby, each species have a separate origin. The fossil record is a possible answer to the history of life.

Page 111

Chapter 6 Review

Questions 21-23  

Methinks It Is Like a Weasel

A simulation showing how natural selection achieves better results for adaptability than random chance by using a target sentence and mutations to arrive at a result. Requires Java

The Weasel Applet

A fun simulation that demonstrates the ability of evolutionary techniques to solve enormous problems rapidly by finding a goal phrase through mutations and adaptation. Requires Java

Richard Dawkin's Weasel

A demonstration of natural selection used in Richard Dawkins' book The Blind Watchmaker. He uses the example of a child typing Shakespeare to illustrate how natural selection can produce unlikely results. Requires Java.

Unit 20B Performance Task-The Sixth Extinction

Mass Extinctions Of The Phanerozoic

A Canadian site which outlines past mass extinctions and their causes.

The Extinction Files
A large BBC site examining previous mass extinctions throughout geological time.

The Sixth Extinction
An article about the current mass extinction of species and how it compares with the five previous mass extinctions in Earth's history.

How Will the Sixth Extinction Affect the Evolution of Species?
An article discussing how the current sixth mass extinction will affect biodiversity and evolution.

The Five Worst Extinctions in Earth's History
Details of the five worst mass extinctions in Earth's history and their possible causes.

National Geographic - The Sixth Extinction
National Geographic article outlining how a mass sixth extinction is not happening because of some external force. It is happening because of us.

How One Creature Drives So Many To Extinction
An article about how Earth is going through its sixth and probably its most devastating period of mass extinction with scores, and possibly hundreds of species of animals and plants dying out each year.

The Sixth Extinction is Already Here
Some predictions estimate that within a quarter of a century over half the worlds species of mammals will become extinct.

A Modern Mass Extinction?
This PBS site has a discussion of whether we are now in a period of mass extinction and the implications for the Earth.

Tree of Live - Video Clip
This video illustrates the increasing rate of extinction of species versus the generation of new species. Requires Real Player.

The Current Mass Extinction
Background information about how we may already be witnessing a mass extinction similar to past mass extinctions of the geological past.

Unit 20B Review
Page 120
34. Evolutionary biologists have hypothesized that many epidemics-widespread diseases that usually kill their hosts, such as smallpox or plague-could only have evolved in large human populations. Further, they hypothesize that these diseases originated in mammals that were domesticated. Consider these
hypotheses in relation to contact between European explorers and indigenous peoples, such as the Arawak, Aztec, Maya, Inca, Aboriginal peoples in North America, Aborigines in Australia, and Maori in New Zealand. Consult print and electronic sources to determine whether the exchange of diseases between
Europeans and any two of the indigenous peoples listed above supports one or both of these hypotheses. Report your findings to your class.

Transmission of Influenza A Viruses Between Animals and People
The site describes which species host influenza A viruses, and the ways Avian influenza viruses are transmitted to humans.

An easy-to-read explanation of how people are infected with the plague, world distribution of plague, and the risk of getting it in today's world.

Natural History
It has been said, that populations have been so affected by plague that sometimes there were not enough people remaining alive to bury the dead. This site describes the history of this ancient disease.

Smallpox Disease Overview
This site describes the disease, where smallpox comes from, and how it is transmitted.

Smallpox: Eradicating the Scourge
The site describes a history of smallpox, and how it spread around the world, including native populations.