Evolution Notes

Understanding Evolution:

Notes:

Darwin and Wallace described the mechanism for evolution

Darwin developed the idea of natural selection, or survival of the fittest

• Most characteristics of organisms are inherited
• More offspring are produced than are able to survive
• Offspring vary in characteristics

Natural selection can only take place if there is variation. These will be spread through mutations and reproduction

Adaptation is a new trait that helps an organism survive

Divergent evolution is the point of change for two species

Biogeography causes different types of evolution to occur to different organisms

Questions 1-8:

1. c

2. b

3. a

4. d

5. Whichever seeds are capable of growing into plants through the more difficult parts of survival demonstrate natural selection.

6. Because they are similar among completely different species - organisms for that matter

7. A theory means tested multiple times without failure

8. A monkey seems more advanced, because of its human-like characteristics. However, they mouse is just as evolved but in a different way.

Formation of New Species:

A species is a group of individual organisms that interbreed and produce fertile, viable offspring

The closer an organism is in species, the more DNA they will have in common

A hybrid is a cross between two species

Many species can create fertile offspring-hybrids

For species to be made, they need to evolve to the point where they cannot interbreed with any other species successfully 

Allopatric speciation is evolution due to change in location

• Dispersal is a simple movement
• Vicariance is a forced geographical change

Sympatric speciation is evolution in the same location

• Mutation
• Aneuploidity is a change in number of chromosomes
• Polyploid is extra

Reproductive isolation

• Prezygotic barrier
• temporal isolation (breed time)
• Behavioral isolation
• Habitat isolation
• Gametic barrier

Questions 1-8:

1. 2n + 1

2. a

3. b

4. b

5. c

6. c

7. c

8. d

Reconnection and Rates of Speciation:

A hybrid zone is where different species that can interbreed create hybrids

• Reinforcement is when the hybrids move away from each other
• Fusion is when the hybrids become one species
• Stability is when the hybrids continue to be produced

Gradual speciation is when species diverge gradually over time in small steps

Punctuated speciation is when a new species undergoes changes quickly from the parent species

Environment has the most effect on speciation

Questions 3 - 4

3. a

4. c

Population Evolution:

Modern synthesis is how natural selection plays a part in speciation

Microevolution is a change in a population’s genetic structure

Macroevolution is evolutionary changes on a broader scale

Gene pool is the sum of all alleles in a population

Traits

Heredity and Traits Think Quest

1.    Go to the following website: http://learn.genetics.utah.edu/content/begin/traits/

2.    Click on “What is Heredity?”  Summarize what heredity is.

They are the genes from parents that are passed onto their offspring. These genes can be found in the DNA of the first 46 chromosomes we are given. For the child to be healthy, it needs to receive exactly one of each chromosome.

3.    Click on “What is a Trait?”  Summarize what a trait is in your own words.

Traits are notable characteristic of someone, and are passed throughout generations. Physical traits are noticeable, as they deal with appearance, and are inherited. They can also be changed by the environment, like the sun changes hair color. Behavioral traits deal more with instincts, and are most notable in sheepdog, and how well they herd. These traits can be changed, through learning. People can also inherit “disease traits” of their parents. This can be changed, as well, by diet and exercise. Traits that are inherited are either homozygous or heterozygous, which deal with the alleles.  Complex traits are also common, which show a blend of multiple alleles.

4.    Click on “What is a Chromosome?”  Describe the structure of a chromosome.
Chromosomes are made up of DNA, which are wrapped compactly around proteins. Humans have 46, or 23 pairs. This is not the same for all organisms.

5.    Click on “How Do Scientists Read Chromosomes?”  Describe how karyotypes are used.

Size, banding, and centromere position.

6.    Click on “Make A Karyotype.”  Do this activity.  Describe how you knew where to place each chromosome.

Based on their size.

7.    How do scientists predict genetic disorders?

8.    What are telomeres and what is significant about them?

They are the ends of chromosomes, and they help protect them from sticking to each other.

9.    How is genealogy tracked in humans?

Family tree, and telomeres through the blood cells.

10. Look at your own avatar. 

a.     Are the traits you listed for your avatar consistent with what you’ve learned today?  Why or why not? 

b.    Based on what you’ve learned today, do you need to adjust anything about your avatar’s traits or its habitat?  Explain.

c.     Create a genealogy for your avatar going back at least to the grandparents.  Sketch this here or on a separate piece of paper.  Label at least one of the traits on your genealogy.

Hardy Weinberg Lab Report

Hardy Weinberg Lab Report Recessive Allele Survivability AP Biology, Mod 19 Abstract. The theory of recessive allele survivability and its relation to hairless rabbits was examined by using the Hardy Weinberg Model. The survivability of recessive alleles was examined by selecting red and white beads from a bowl to symbolize recessive and dominant alleles - the recessive being white and the dominant being red. The recessive alleles slowly dwindled down to four alleles in the tenth generation, from the original 50, symbolizing the death of the hairless rabbits due to the cold weather. No preference for tree circumference was noted. These data suggest that beaver food choice concurs with the optimal foraging theory. Introduction In this lab, we explore the diminishing presence of recessive alleles, specifically that within hairless rabbits vs. haired rabbits. It is suspected that, through natural selection, the recessive alleles that cause an inhibition on an organism will cause those organisms to die off - making the presence of that recessive alleles less likely to be in the next generation of organisms. In the case of the hairless rabbits, they would die off in the colder months, and the haired rabbits would survive to pass on their genes. The significance of the survivability of recessive alleles is important for the theory of evolution and natural selection. The extinction of millions of different species has aided in the process of evolution for other organisms. Without the disappearing of recessive alleles, it would be very difficult to survive for the organism carrying them. They would have many disadvantages.        The main objective of this lab was to see the process of natural selection taking its course in nature, specifically in hairless rabbits. They make a good example, because they die off more quickly due to the harsh winters of England. This proves that survival of the fittest does take place.        We hypothesized that, through the generations, the hairless rabbits would die off, and the dominant alleled rabbits would soon become the only rabbits to live. We believed this to be true, because - given time - every combination possible will take place, and all of the white rabbits would end up dying. Of course, with only ten generations to work with, some did survive, because not all combinations took place. Methods To show the genes being passed down generation to generation, we used beads to represent the bunnies and the offspring. We used the red beads as ‘F’(dominant) and the white as ‘f’(recessive), we dumped 50 of each into a bowl and picked 2 beads without looking. The two beads we picked out would determine the genes for the offspring. We did this until there were no more beads in the bowl and recorded our results on a table that had 3 columns for each outcome. We would keep the ‘ff’ pairs out of the bowl and repeat the process until we had no more ‘f’ alleles in the bowl, or until we had repeated the lab 10 times (reaching the end of the chart). Eventually, the ‘F’ alleles would be the only beads in the bowl, or the recessive gene would stay in due to chance. Results In the experiment we found, similar to what we predicted, the FF rabbits grew in number, and the ff decreased. Because we were not given infinite amount of time, there were still some ff alleled rabbits that survied: about 2. As shown in the graph, however, there is a clear positive curve for the FF alleled rabbits. The ff alleled rabbits saw a negative curve, which we also predicted. For the Ff alleles, we also saw a negative curve. This makes sense, but we did not predict it in our hypothesis, because it was not an outcome we took into account. Of course, if the white beads would slowly be taken out, then any combination of white beads would diminish - double or alternating between white and red. Discussion The Hardy-weinberg formula allows scientists to determine whether evolution has occurred. Any changes in the gene frequencies in the population over time can be detected. The law essentially states that if no evolution is occurring, then an equilibrium of allele frequencies will remain in effect in each succeeding generation of sexually reproducing individuals. In order for equilibrium to remain in effect, then no mutations, gene flow, or selection can occur. Random mating must occur and the population must be big enough so that no genetic drift can cause the allele frequencies to change. The result of this lab was that as each furless rabbit died off in the previous generation, there would be a decrease in the amount of furless rabbits in the next generation. This is because as the alleles die off, in one generation, it becomes less likely for them to be present in the next generation. Eventually, there will be no more recessive pairs of alleles, as seen in the 10th generation of this lab. The probability of the recessive allele pairs surviving got slimmer through each generation. This lab gave us the opportunity to observe how a specific recessive allele pairs become less likely to appear in an environment that does not suit them. Although some of the hairless rabbits survived through the generations, eventually all the furless rabbits did not survive anymore. Conclusion The purpose of this lab was to learn about the recessive allele survivability  by using red and white beads for hairless rabbit survivability. We now know that the Hardy Weinberg model  allows us to predict the survival rate of hairless rabbits in England. We were able to observe and record survival of the fittest in the lab as the bunnies with the recessive genes couldn’t withstand the environment while the bunnies with two dominant genes or a dominant and recessive continued to live.

Geological Time Scale

3. Take notes on the activity and discuss the geologic time scale as you proceed. Make sure to include explanations for the following (you may include more):

a. Relative dating

Relative order puts events in order from earliest, to most recent.

b. Absolute dating

c. Approximately how old is the Earth?

The Earth is about 4,600,000,000 years old

d. When did life first appear on the Earth?

The first life appeared 3,900,000,000 years ago

e. Law of Superposition

Rock layers are deposited on top of layers that were already there. As more and more layers are deposited, the older rock layers end up at the bottom of the sequence and the newer ones toward the top.

f. Vertical timeline (what does it demonstrate?)

It shows the relative order of events and helps us see connections between events, records are kept to be easily put in order for evidence.

g. Trilobites

Trilobites ("three lobes") are so called because their bodies are divided into three lobes: a middle lobe and one on either side. They first appeared about 540 million years ago.

h. Brachiopods

Brachiopods are marine animals that look a bit like clams. They are still common in cold waters today, but the height of their diversity occurred about 400 million years ago.

i. Radiometric dating

Radiometric dating gives absolute dates using the molecular compositions of the substances surrounding fossils.

j. Eurypterids

The eurypterids were one of the fiercest predators in ancient seas. Some reached more than two meters (six feet) in length, making them the largest arthropods that ever lived. The last ones went extinct about 245 million years ago.

k. Ammonites

Chambered mollusc, similar to today’s mollusc

l. Geologic Time Scale

It represents the entire history of the Earth since its formation, roughly 4.6 billion years ago.The Geologic Time Scale is broken up into several periods of time, during which there were great changes in the biodiversity on Earth.

m. Name the Eons and their major events

-Pre-Archean was before Archean, no evidence supports life during this eon.

-Archean: “original”, this was when the first single-cell organisms began to evolve.

-Proterozoic means "before animal life" which isn’t accurate, but most organisms during this time were simple, this is when algae and worm-like creatures were evolving.

-The Phanerozoic Eon is when complex life started to form on earth. It began with the start of the Cambrian period, 544 million years ago, when most of the major groups of animals first appear in the fossil record, and continues through today.

n. Name the Eras and their major events

Cenozoic: “recent life” Mammals, birds, flowering plants became more abundant during this time.

Mesozoic: Mesozoic means "middle life." Dinosaurs, cycads, and ferns were abundant during the Mesozoic.

Paleozoic: “ancient life” Many animals of today originated then like certain corals and brachipods

o. Name the Periods and their major events

-Cambrian: when most of the major groups of animals first appear in the fossil record.

-Ordovician: known for its diverse marine invertebrates and for the presence of early vertebrates.

Silurian: Coral reefs first started forming and an important time for the evolution of fish

Devonian: The first plants began showing up and growing

Carboniferous: Coal began forming in large deposits, and insects began evolving

Permian: When all of the continents came together to form Pangea, and ended with the largest mass extinction in the history of earth.

Triassic: The animals that survived the mass extinction continued to evolve

Jurassic:  Plant eating dinosaurs dominated the earth. Smaller carnivores ate the larger herbivores.

Cretaceous: Ceratopsian dinosaurs came into existence. Many non-avian dinosaurs became extinct.

Tertiary: Many flowering plants evolved, as well as modern-looking mammals

Quaternary: Mammoths and mastodons, sabre-toothed cats, etc. roamed North America, Asia, and Europe. Most of the world temperate zones were covered by glaciers and uncovered by the warm periods.

p. When did humans come along?

Humans came along in the Quaternary Period along with mammoths, saber tooth tigers, etc.

r. What questions do you still have?

Origin of Life Think Quest

Origin Of Life Think Quest

Activities / Procedures:
1. In your small groups, read the following quote from a New York Times article:  “Enshrined in high school textbooks, the Miller-Urey experiment raised expectations that scientists could unravel the origins of life with simple chemistry experiments.”

2. Now, use your online textbooks and the following videos: http://www.youtube.com/watch?v=j9ZRHoawyOg and http://www.youtube.com/watch?v=63IoOLXmzKg(Familiarize yourself with the famous Miller-Urey experiments of 1953 by completing the following Think Quest that will prepare you for reading an article about new evidence related to these experiments.

Quest Questions (post answers in your online notebook under “Notes”:
-Who were Stanley Miller and Harold Urey? Scientists who discovered how organic, life substances could be formed under the conditions the atmosphere was under during the first years of the earth’s existence.
-What was the Miller-Urey experiment trying to simulate? The conditions of the atmosphere.
-When was the Miller-Urey Experiment performed? During the early 50’s.

-Describe the Miller-Urey Experiment. They recreated atmospheric conditions during the first years of life, and subjected them to either electricity or freezing, and observed what molecules were created.
-What was discovered by the Miller-Urey Experiment? That amino acids and adenine could be created under the above-mentioned conditions.
-Are the results of the Miller-Urey Experiment still considered relevant today? Why or why not? Yes, but by a much more varying degree from when it was first introduced. There are so many more hypothesis now, that the amino acids could have formed from meteorites from space.

--Compare and contrast this experiment to your “Coacervates Lab” (review it in your online notebook). We were able to create cell-like organisms through the use of carbohydrates and proteins.
- List any Need to Knows you have concerning the experiment and the conclusions. Did all of these organisms form together to make the first cells?

- What was the significance of the swan-neck flask experiments and who performed them? It proved that spontaneous generation did not exist, and there were no vital substances in the air for living. Louis Pasteur conducted this experiment.

- What was the significance of the blender experiments and who performed them? Alfred Hershey and Martha Chase used a kitchen blender to prove that DNA exists, and how viruses infect their hosts.

- How do the blender, swan-neck flask, and Urey-Miller experiments relate to one another and your current project? Through the incorporation of all of the created molecules, life is possible to be made. With our current project, we are talking about the evolution of animals, and the fact that the environment surrounding can affect organisms, we will be able to have our organism evolve.

3.  With your partners, read and discuss the article “From Old Vials, New Hints on Origin of Life,” (http://www.nytimes.com/learning/teachers/featured_articles/20081021tuesday.html) focusing on the following questions:
a. What would a proponent of Dr. Miller say about his experiment today? What would a critic say about it? They would say that there are so many variables in which life could have taken place. A critic would say that it is very improbable that anything of such degree could have taken place.
b. Why did the addition of steam to the experiment by Dr. Miller interest Dr. Jeffrey L. Bada? The H2O made for a better environment for chemical reactions to take place.
c. What did Dr. Bada and Adam Johnson discover in the “brown residue at the bottom of an old vial?” Why was it significant? There were more amino acids than originally conceived by man, and it helped the believe that – certainly – complex proteins could have been formed in these conditions.
d. What other places have been suggested as likely locations for the origin of life and why? Do you agree or disagree with Dr. Bada’s assessment that “you want to consider everything,” and why or why not? The ocean was considered. Yes, you do want to consider everything, because given billions of years, life had to start from somewhere. If simulated, then we can find the origins of life.

e. How does knowing about climate past and present help us understand life and how it survives? We are able to see under what conditions life can be sustained.

f. Do you think we have a responsibility to attempt to curtail or reverse human’s influences on the environment?  Why or why not? Yes, because we are the more conscious beings on earth. We subjected the earth to these conditions, and now we are responsible for bringing it back to a healthy state.

Evolution Reflection

1. Does evolution tend to proceed slowly and steadily or in quick jumps?

I think it varies. Clearly, humans evolved over thousands of years, and that was just a short span of time. For plants, it took millions of years. This shows that it is not the same for all species, and depends on the environment.

1. Why are some clades very diverse and some unusually sparse?

Depending on their location, some may need not evolve any more. If they have reached a point where they can survive with no problems, then they do not need to evolve to adapt to their environment.

1. How does evolution produce new and complex features?

Evolution produces new features, because organisms are constantly needing to adapt in the changing world. Because the world is experiencing a warm up period, life will have to evolve it's features to survive.

1. Are there trends in evolution, and if so, what processes generate them?

Yes, there is a trend. Organisms evolve based on their environment. This inclues predators, climate, and food supply. This all changes with, or without, the organisms. 

Evolution 10/24/13

• Evolution is descent with modification
• Evolution implies biological evolution
• All life on earth shares a common ancestor
• Phylogeny is the evolutionary tree at which species evolve, and is a hypothesis on the relationships among organisms
• Moving through a phylogeny is moving through time
• A split represents a branching on phylogeny
• Each part of the phylogeny is specifically unique
• They are trees, not ladders
• Characteristics of the animals/species help with ordering them
• The species that is most important to the biologist goes on the right
• Homologous characteristics are those that are similar among species
• Bird and bat wings are analogous, which mean they have separate evolutionary origins, even though they look similar
• It is used for classifying organisms, as well
• Linnaean system: Kingdom, Phylum, Class, Order, Family, Genus, Species
• A clade is a group that shares a common ancestor
• The chart allows for easy distinguishing of relationships
• Humans are very young
• Radiometric dating relies on half life decay to discover the times at which things lived
• Stratigraphy uses other dates to estimate the time
• Molecular Clocks allow genetic divergence between organisms for time estimates
• Descent and the genetic differences that are heritable and passed on to the next generation;
• Mutation, migration (gene flow), genetic drift, and natural selection as mechanisms of change;
• The importance of genetic variation
• The random nature of genetic drift and the effects of a reduction in genetic variation;
• How variation, differential reproduction, and heredity result in evolution by natural selection; and
• How different species can affect each other's evolution through coevolution.
• Mutation is an unnatural, random change of genes
• Migration is when two different species of organisms interact
• Genetic drift is when a certain type of organism is diminished, and less of that organism's genes will be passed down
• Natural selection is survival of the fittest
• Fitness is how well an organism can leave offspring alive
• Sexual selection is the ability for an organism to find a mate, easily. Sometimes, organisms go to extreme lengths to find a mate. If is not successful, it will not pass on its genes
• Artificial selection is when humans are involved in the process of sexual selection
• Adaptation helps for organisms to survive
• No such thing as a "perfect organism."
• Coeveolution is when two organisms effect each others morphology
• Microevolution - evolution on a small scale
• A population is a species that interbreed with each other
• The same species can look different, and the different-looking organisms can interbreed
• Speciation event is the birth of a new species
• Isolation causes speciation
• Speciation can also be caused by a difference in mating rituals
• Lack of fit of genitals
• Cospeciation is when two organisms effect the speciatition of another organism
• Macroevolution is evolution on a grand scale
• It is involved in the tree of life
• 3.8 billion years is macro
• Many species find a stasis, from which they will not evolve much
• Lineages can change quickly or slowly
• Extinction plays a big part in macroevolution