Evolution and Adaptation Student Guided Notes

Evidence of Evolution – Book 1

Development of a Theory

More than anyone else, a young Englishman named _________________________ made great contributions to our understanding of ______________________. In 1831 he set sail on the _________________________ to travel the world. During his 5 year voyage Darwin's observations helped him to realize that an

__________________________________________________________. He also realized that the diversity of life he observed was only one part of a much larger puzzle. ___________________________________________________________ ___________________________________________________________. As a result of these observations Darwin sought to answer two questions: Where did all of these different organisms come from? and secondly, Why have so many of them disappeared over time? Darwin was also impressed by the many _________________________________________________ that enable organisms to ______________________________________ in their environment. He termed this _____________________ Darwin also wondered ____________________________________________ _______________________________________________________ ________________________________________________________ 30 years after working to answer these questions, Darwin published his book called ________________ _________________________________________. This book changed the way people think about the living world. In his book Darwin maintained that modern organisms were produced by a process call _______________________________.

What is Evolution?

The idea that life on Earth has changed over time, is very old. Scientists have accumulated considerable evidence to show that organisms alive today have been produced by a long process of change over time. The process by which modern organisms have descended from ancient organisms is called _________________________ Evolution, in

the broadest sense, simply means _____________ but is better known by the following definitions: "A _______________________________ in which something changes into a different and usually _____________________________________" - answers.com (ie. all organisms come from a common ancestor) "Evolution: The gradual process by which the ______________________________________________ ________________________________________________, which is believed to have been continuing for the past __________________________." - Oxford Concise Science This unit will have a look at the highly debated topic of Evolution. Theory or not? That will be for each of you to decide for yourselves as you work through the assignments. Evidence Supporting Evolution: 1) Fossil record. 2) Biochemical and Molecular Biology. 3) Biological Evolution. 4) Biogeography. 5) Embryology and development. 6) Comparative Anatomy.

The Fossil Record

Layers of ________________________________ contain _________________.

New layers ________________________, creating a ______________________________________. Fossils are ___________________________________ ___________________________________________. Most fossils are formed from being covered by sediment. The soft parts of an organism most likely will be decomposed, however sometimes they leave an____________________ if covered quickly.

___________________________________________________________. _______________________________ is found in the strata of the sedimentary rock________ ________________________________, and _____________________________________ ______________________. Fossils within layers show that a succession of organisms have populated Earth throughout a long period of time. Dating fossils is a very difficult process. Scientists use _______________________________ to date fossils. Isotopes have a half-life measured in time. This means that after a period of

time (half life) the original radioactive isotope will decrease by half the original sample allowing scientists to estimate time periods. For example, Carbon 14' half life is 5,730 years. The fossil record is a record showing us that today’s organisms _______________________ ______________________________.

Archeopteryx

The illustration below is of Archeopteryx. It represents a _____________________________________ _______________________________ found in an area of present day Germany. Archaeopteryx many have been a ______________________________ that provides evidence of an evolutionary connection between primitive _____________________________________. The fossil has _______________

___________________________________________________________ Other examples of transitional animals are Eustheopteron, a lobe finned fish ancestral to amphibians, and Seymouria, an amphibian ancestral to reptiles. The fossil record can help __________________________________________________ ________________________________. The diagram below shows the changes in elephants over the past 25 million years.

Biochemistry and Molecular Biology

_________________ consists of cells. The _________________________________. DNA is ___________________________________________________. ____________________ in both DNA and other chemical compounds __________________

______________________________________. ________ (Deoxyribonucleic Acid______________________________ building blocks called ________________________. These nucleotides are composed of _______________ (deoxyribose) and ____________________ which make up the backbone of the double helix, __________________________________________________ ____________________________________________ that make up the rungs of the DNA ladder. The four bases ____________pair up in the following way: ________________________________________ This if referred to as _______________________________________. The ____________________________________ of A's, C's, G's, and T's is what makes the organism a dandelion or a human. ___________

____________________________________________________________ (please see this page for a human evolution article.)

Therefore, it is the _____________________________________________________________________________________________________________________________________________________:

For example, the DNA difference between humans and chimpanzees is _________ but the difference between humans and lemurs is __________ This displays a closer relationship between __________________________________________________________________ Biochemical similarities between organisms are closely related to the ___________________ _________________ they possess. The role of DNA in evolution is clear______________________________________________ _________________ within organisms upon which __________________________________ ___________________. Other biochemical compounds such as similarities in specific proteins found in different species can also suggest an evolutionary relationship. For example, let's use the protein Hemoglobin that carries oxygen in our red blood cells. _____ ______________________________________________________________________________________________________________________________________________________

______________________________________________________ ______________________________________________________. ______________________________________________________ ______________________________________________________ The change of_______________________ of organisms _______________________________________ A population is a group of members of _____________________________________ _______________________________________________________ Small changes in many species have been observed throughout time. However, the change or ______________________________ has often been ________________________________ Many organisms such as specialized dog breeds or crop plants look very little like their ancestors. These organisms were ______________________________ to have a specific ______________________________________. Other organisms have changed due to human influence with less conscious human intervention. For example______________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________________. The population changed due to the white moths being selected against.

Examples like the peppered moth show us that ____________________ have the ability to _______________________with changing environments so this is a likely reason for the diversity of life on earth today.

Click here to read about the Peppered Moth and attempt a simulation activity. Use what you learn to answer the following questions:

1. How did pollution affect the peppered moth population in industrial England? __________________________________________________________________________________________________________________________________________________________________________________________________________________

2. Explain the process that led to these changes in the moth population? ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

3. What do you anticipate would happen to a predominantly light colored peppered moth population if a new form of lichen were to take over the tree bark? This new lichen is neither light nor dark. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Biogeographical Evolution

_______________________________________________________________________________________________________________________________________________Where these plants and animals are distributed is related to their evolutionary history. Organisms evolve in one location and may move into other areas. For example, rabbits are not found in South America. These rabbits must have evolved somewhere else and did not reach South America. The _______________________________________________ can explain the reasons why some organisms ____________________________________________________________ ________________________. The Continental Drift Theory refers to the observation that the __________________________________________________________________________ _______________________________________. This theory explains the close ___________ ____________________________________ of the east coast of South America with west coast of Africa and other continental edges. ________________________________________ ______________________________________________________________________________________________________________________________________________________ ________________________________________________. The present day distribution of mammals is related to _________________ found that support this distribution. Continental drift may also have been a factor in the development of the ___________________________ ______________________________. Modern day similarities may be related to the fact that __________________________________________________________________________

Embryology

There is similar ____________________________________

________________________________________________ . Similarities fade as _______________________________ .These similarities suggests a ________________________ ______________________ for many animal species.

Comparative Anatomy

Comparative anatomy is the ___________________________________________________ with regard to homologous organs or parts.

1. Homologous structures: structures that have ______________________________ ___________________, but have been modified for that species’ purpose. -_____________________________________ -_____________________________________ -_____________________________________ -___________________________________________________ -recent common ancestor

Example: Mammals have same bones in their _________________________________ _________________________________________________ These forelimbs contain the __________________________________________________________________ ______________________. The simplest explanation is a ______________________ _____________________________________________________________________. These forelimbs are referred to as _________________________________________. Homologous structures are similar structures derived from the decent of a common ancestor.

2. Analogous Structures:____________________

,_____________________ but development was from different origins and __________________ _______________________ (recently anyways). Examples: bat wing, bird wing and butterfly wing

3. Vestigial Structures: _____________________ ____________________________________________________. Some of us can wiggle our ears like horses or cats that move their ears to locate sounds. We still have the muscles to do it but ______________________________________ ________________________ Here is a video discussing other vestigial features.

Examples: _______________________________, pelvic bones in whales, male Nipple, wings on emu.

Origin of Life

A highly debatable topic is the __________________________________________________ _____________________________ and cells. The debate is not one for evolutionary biologists but for biochemists. The _______________________________________________ ___________________________________ and is not meant to explain how the first cell came about. Experiments such as Stanley Miller's have been done that show that given the conditions of primitive earth organic compounds could form. Further experiments can show that given a high concentration of organic molecules such as that of the __________________ _______________________________________________________________________________________________________________________________________

Once a protocell is formed further development is explainable by biological evolution.

Evolutionary Theorists – Book 2

Jean Lamarck

______________________________________ (1744-1829) was among the first scientists to recognize that living things changed over time. He also realized that organisms were somehow ____________________________________________________. Lamarck put forth two "laws". First, he suggested that _________ ____________________________________________________. The changing needs brings about a changed behavior, and that behavior change ______________________________________ ____________________________________________________ ____________________________________________________ within the lifetime of the organism. Secondly, Lamarck argued that all changes in organisms could be ___________________. His theory could be sumarized as:

1 species may evolve into many species can __________________________________ during their lifetime these _________________________________________________________________

________________________ new species evolve over time as they acquire more and more

differences. The problem with Lamarck's theory of evolution was the misconception that ______________________________________ _________________________________ Today we know that ______________________________________________________ (Lamarck's theories were published about 100 years before Mendel's work in Genetics was accepted and the mechanism of inheritance was understood.) Using the Buff Baby example, here is what Lamarck believed. Would Arnold's baby really look like this?

Example of Lamarckian Evolution

How the Giraffe got its long neck!!!

Influences on Darwin Ideas that shaped Darwin's theory of Evolution: 1) _____________________________ (geologist) - the __________________________________________________. This was important to Darwin's theory as it would have taken billions of years for millions of species to have evolved from a common ancestor. 2) Farmers - Darwin learned that ________________________ ________________________________________________________________________ Farmers noted the _________________________________________________________ ___________________________________________ For example some cows produced lots

of milk while others only produced a little. Farmers could use these variations to their advantage _______________ __________________________________________ to use as breeding stock. 3. Thomas Malthus (economist) ______________________ _______________________________________________ which he surmised would eventually result in famine, disease, and death . Darwin realized that this also held true for all other organisms and the end result would be

______________________________________________________________________

Darwin's Theory of Evolution The Premise - Darwin's Theory of Evolution is the widely held notion that ________________ _________________________________________: the birds and the bananas, the fishes and the flowers -- all related. Darwin's general theory stresses a purely naturalistic (undirected) "_____________________________________________". That is, complex creatures evolve from more simplistic ancestors naturally over time. In a nutshell, as random genetic mutations occur within an organism's genetic code, the _______________________________________ because _____________________________________ -- a process known as "natural selection." These ______________ _____________________________________________ _____________________. Over long periods of time, beneficial mutations accumulate and the result is an entirely different organism (not just a variation of the original, but an entirely different creature). eg. reptilian ancestor to acheopteryx to birds Natural Selection - Natural selection is the preservation of a _______________________ _____________________________________ _____________________________________ Over the centuries, human breeders have produced dramatic changes in domestic animal

populations by selecting individuals to breed. Breeders eliminate undesirable traits gradually over time. Similarly, natural selection eliminates inferior species gradually over time. His theory could be summarized as:

1 species can _________________________________________ Individuals have ______________________________________________________ ___________________________________________________________________ Natural selection also known as "_________________________________________

Evidence for Evolution by Natural Selection As you have seen previously the color of the Peppered Moths that survive and are able to pass on their traits to the next generation is based on their ________________________________ _____________________________________. The peppered moth provides a good example of evolution based on natural selection.

This is called ___________________ _____________________ (triggered by human modifications of the environment (pollution) there is an increase in the dark moths). In summary, the pepper moth prior to the industrial revolution was usually

white, but some of the moths were black. ________________________________________ __________________________________ the black moths were selected for when the trees were darkened with soot. The population changed due to the white moths being selected against. Examples like the peppered moth show us that organisms have the ______________ _______________________________________________________ so this is a likely reason for the diversity on earth today.

Adaptation vs Mutation Adaptation: _________________________________________________________________ __________________________________________________________________. Always advantageous (positive). Mutation: a change in DNA that can cause an ______________________________________ _______________________________________________ Neither are a conscious effort to change physiology/structure. The mutation in DNA can lead to changes in proteins.

DNA Mutation Protein Mutation Changes in Proteins can result in

new traits

What Darwin didn't know... Although he knew there was variation, Darwin did not understand ______________________ ___________________________________________________________________________ ___________________________. The structure of DNA wasn't established by Watson and Crick for another 80 years.

DNA and Evolution

Mendel's work in genetics provided the following:

________________________________________________________________. _____________________________________________________________________. ________________________________________________, Natural Selection is not. Natural Selection tests the combination of genes.

Results of Evolutionary Change

There are_____ ways that species characteristics may change: 1) __________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ Large scale: ________________________________ the creation of the current ___________________________ _________________on earth from the first living cells. Small scale: responsible for the evolution of humans and apes from a common primate ancestor. When Darwin sailed the Galapagos Island, he observed that the islands contained a larger variety of finches than found in Ecuador. He noticed that _____________________

___________________________________________________________________________ __________________________________________________________________. Different conditions on each island resulted in different selective pressures on the organisms creating a greater amount of diversity. Example: Darwin’s finches were dispersed to a variety of islands around the Galapagos with various food sources. The beaks are different for each type of finch that lives in a different area and eats a different type of food. If you _____________________________________________________________________ ____________________________________________________.

Artificial Selection ____________________________________________ _____________________________________________ _____________________________________________ All domestic dogs, Canis familiaris, are the same species. Dogs have been _______________ ___________________________________________________________________________ __________________________________ Selection is sped up many times beyond what would have occurred in nature. 2) Convergence - _____________________ ____________________________________ ____________________________________ . This is not a result of evolution from a common ancestor. ____________________________________ ____________________________________ ____________________________________ ____________________________________.

Example: Hummingbirds and moths. One is a bird and the other is an insect, but ________________________________________ ___________________________________________________________________________ _____________________________________________________. Unrelated species become physically similar. Just like the dolphins and sharks below.

Results of Evolutionary Change con't Paralell or Coevolution- coevolution can be defined _________________________________ _______________________________________. The members of a coevolving pair ____________ _______________________________________ ___________________________ so that their _______________________________________ _______________________________________ ______________________________________ ______________________________________ ______________________________________ ________________________________. This acacia plant provides nectar for the ants inside its hollow thorn. The ants defend the plant from herbivores!

Speciation Speciation is a ______________________________ ________________________________________________ ________________________. Looking at a tree of life that constitutes a species of fruit fly, ________________________ _________________________________________________. At that point _______________________________________

where previously there had just been one. But why and how did it happen? The branching points on this fruit fly phylogeny represent long past speciation events. Here is one example to show how speciation might occur:

The scene: a population of fruit flies cheerfully laying their eggs in the mushy fruit...

Disaster strikes: A hurricane washes the bananas with the immature fruit flies out to sea. The banana bunch eventually washes up on an island off the coast of the mainland. The fruit flies mature and emerge from their slimy nursery onto the lonely island.

The populations diverge: Ecological conditions are slightly different on the island, and the island population evolves under different selective pressures and experiences different random events than the mainland population does. Morphology, food preferences, and courtship displays change over the course of many generations of natural selection.

So we meet again: If _________________ _______________ lasts long enough, when the two populations are reintroduced, they can no longer mate or produce viable offspring due to different courtship behaviors, mating seasons, genetics etc. The lineage has split from one species into two.

This is a simplified model of speciation where members of the same species become ________________________________________________. Because they are geographically isolated the two populations can no longer interbreed (_______________________________). This example gives an idea of some of the processes that might be at work in speciation. Geographic barriers such as _______________________ ______________________________________________ may separate sub-populations and prevent them from interbreeding. Once __________________________________ occurs, natural selection usually increases the differences between the separated populations. As the populations become better adapted to different environments, their separate

__________________________ gradually become more dissimilar. If the populations remain separated for a long time, their gene pools eventually become so different that their reproductive isolation becomes permanent. The result is _______________________. Speciation as the result of geographic isolation is called ____________________________________________. If a population is separated into two different reproductively isolated groups without geographic isolation, it is called __________________________________________. Following are some examples of sympatric speciation:

______________ ______________ ______________ _____________ ______________ ______________ ______________ ______________ _____________ _____________

Rate of Evolution There are two interpretations about the pace or speed of evolution that are based on the fossil record: 1. Gradualism A traditional view that states _____________________________ ___________________________________________________ _____________________ in an organism. Darwinian evolution - not much evidence that this is how it works. 2. Punctuated Equilibrium Model This model states that evolution proceeds with ______________. ___________________________________________________ _________________________ Speciation occurs during _____

___________________________________________________. The fossil record seems to indicate that many species existed without change for long periods of time. ___________________ ___________________________________________________ _________________________. Changes occurred in a few thousand rather than a few million years.

Agents of Evolutionary Change – Book 3

Conditions Affecting Evolution No Evolutionary Change = Hardy Weinberg Principle. The ______________________________________ suggests that if a population is not evolving the allele frequencies in the population ________________________. This stable condition was called ___________________________________________. The Hardy-Weinberg Principle states that: “_____________ _______________________________________________ _______________________________________________ ____________________________________”. Shown mathematically by: ______________________________________ where ________________________________________________ ________________________________________________ Hardy Weinberg As stated previously, Hardy-Weinberg Principle = No Evolution. The principle is based on 5 assumptions. ________________________________________ _______________________________________________________. The conditions required to maintain genetic equilibrium are:

1. Mutations _______________________________. 2. Individuals neither leave or enter the population.

(_____________________________________________________) 3. Population is ____________________________. 4. _______________________________________________. 5. ________________________________________________ does not occur.

Breaking the Hardy Weinberg Principle = Evolution Reality is:

1. ___________________________________________ 2. Individuals _________________________________________ the population. 3. Populations ________________________________. 4. _____________________________________________________________ 5. ____________________________________________________________.

Evolutionary Change occurs when one of the requirements of genetic equilibrium are broken. _________________________________________________________________________.

__________________________________________________________________________: 1. Mutations.2. Genetic drift. 3. Gene flow or Migration.4. Non-random mating. 5. Natural selection.

Mutations

Mutations are changes in the _________ _________________________________. Mutations DO occur although the rate of mutations in most species is not currently well understood. We expect that mutations occur at a low rate under normal conditions. We know they occur at a higher rate if mutagens are present. Genetic Drift ________________________________________________________________________. (ex. bigger, stronger, faster, smarter). Genetic Drift

The random change _________________________________ _______________________ due to a ____________________ ____________________. In the small frog population below, death of a couple of brown frogs results in no brown frogs in the next generation. __________________________________________________ __________________________________________________ Every gene “counts” in small populations. Bottle Neck Effect

Genetic drift can create a _______________________. Populations that are near extinction because of a natural disaster endure a bottleneck effect. Again, change alone may determine which individuals survive these unfavourable times, which act as a bottleneck, ____________ __________________________________________________________________________ _________________________________________________________________________ For example, cheetahs have certain enzymes that are identical even though there are 47 enzymes that can come in different forms. This demonstrates that genetic drift can cause certain alleles to be lost from a population.

Individuals DO Enter and Leave Populations. Immigration is where _______________________________________________________. Emigration is where ________________________________________________________. _________________________________________________________________________ __________________________________________________________________. Canadians, for example, are free to move around the country to go to school or seek employment opportunities. If they find partners in their new location and have offspring gene flow has occurred. Non-random Mating Individuals ____________________ mate randomly. The result of _____________________ ____________________ is that ________________________________________________ ______________________________ and thus ________________________________ (and more copies of their genes) than others. In animals, individuals _______________________ __________________________________________________________________________. Mate selection is often influenced by things like ____________________________________ ___________________________________________________________________ Assortative mating may also take place where selection of a mate is based on similar characteristics. Natural Selection "the non-random survival of random variants" -Richard Dawkins Only the ___________________________________________________________________ __________________________________________________________________________ ____________________________________. Those that are less well adapted tend to be eliminated. This is the single most important factor that effects genetic equilibrium and drives evolutionary change. Recall that __________________________________________________________________ ___________________________________________________________________________ …..the peppered moth for instance. Charles Darwin was the first to explain evolution by natural selection. Many other theorist tried to explain evolution but have been discredited.

Darwin vs. Lamarck

Larmark Darwin

Example

Example

Summary

Summary

The ability to survive is related to the ____________________________________________. Fitness of the individual is measured by __________________________________________ _____________________________________________________________________. Gene mutation is the ultimate source of variation.

Different Types of natural Selection Natural selection can take many forms. To make talking about this easier, wewill consider the distribution of traits across a population in graphical form. In a graph we can see the normal bell curve of trait distribution. For example, if we were talking about height as a trait, we would see that without any selection pressure on this trait, the heights of individuals in a population would vary, with most individuals being of an average height and fewer being extremely short or extremely tall. However, _____________________________ __________________________________________________________________________. 1. Stabilizing Selection ______________________________________________________ ______________________________________________________ ______________________________________________________ while individuals at both ends of the _________________________ ______________________________________________________ ______________________________. When selective pressures select _________________________________________________ _______________________________________________. For example, plant height might be acted on by stabilizing selection. A plant that is too short may not be able to compete with other plants for sunlight. However, extremely tall plants may be more susceptible to wind damage. Combined, these two selection pressures select to maintain plants of medium height. The number of plants of medium height will increase while the numbers of short and tall plants will decrease. 2. Directional Selection ____________________________________________________________ ____________________________________________________________ ____________________________________________________________. Directional selection occurs when a change in the environment favors this extreme phenotype. The result is that the population's trait distribution shifts toward the favorable extreme. In the case of such selection, the mean of the population graph shifts. Using the familiar example of giraffe necks, there was a selection pressure against short necks, since individuals with short necks could not reach as many leaves on which to feed. As a result, the distribution of neck length shifted to favor individuals with long necks. 3. Disruptive Selection ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ _______________________ This is rare in nature but suggests why speciation could occur without population segregation.

In disruptive selection, selection pressures act against individuals in the middle of the trait distribution. The result is a two-peaked curve in which the two extremes of the curve create

their own smaller curves. For example, imagine a plant of extremely variable height that is pollinated by three different pollinators, one that was attracted to short plants, another that preferred plants of medium height and a third that visited only the tallest plants. If the pollinator that preferred plants of medium height disappeared from an area, medium height plants would be selected against and the population would tend toward both short and tall, but not medium height plants.