Download 3. What affects whether or not a mutation is considered

Name: ______________________________
Period______
Webquest: Variation, Selection, and Modern Genetics
Part I: What is Genetic Variation?
Web Address: http://learn.genetics.utah.edu/content/variation/sources/
1. What is variation? Differences within a population of the same species
2. What is a mutation and what are some possible ways they occur?
Primary source of variation; typos in the DNA copying process; miscopying , inserting or deleting a
letter in the DNA code or larger chunks of DNA
3. What affects whether or not a mutation is considered advantageous or disadvantageous?
The environment of the organism it occurs in
4. What is recombination and when does it occur? The shuffling of genes during reproduction to
produce new genetic combinations.
5. What are the sources of variation in a population?
A.Mutation
B._Recombination
Part II: What is Selection?
Web Address: http://learn.genetics.utah.edu/content/variation/artificial/
1. How does nature “select” organisms to survive?Nature favors organisms that are best suited for
their environment, allowing them to survive and reproduce to pass down desired traits to their offspring
2. How are natural and artificial selection similar? Both rely on the principles of inheritance for
maintaining favorable traits from one generation to the next; both cause change over time.
3. What are some examples of organisms that were selectively bred for specific traits?
a.Dogs- hunting and companionship
b.Horses- transportation, hauling, etc
c. Bees- for honey
d. Livestock (cows, sheep, etc) and Crops for food
e. Pigeons- speed, endurance, homing instinct, and beauty
Part III: An Origin of Species
Web Address: http://www.pbs.org/wgbh/evolution/darwin/origin/index.html
1. Explain how variation in the pollenpeepers shaped each population over time to best match its new
environment on each different island. Cite details from one of the islands to support your explanation.
The pollenpeepers were blown to various offshore islands because of a storm. The birds
must adapt to their new environment or die.
I.
Mainland pollenpeepers The original pollenpeeper fed and nested on the ground
which made the species better able to survive in a hurricane. They ate seeds and
insects and had a high level of predators and competition. Overtime, the level of
competition remained intense but the level of predators reduced. The fight for the
limited food source favored birds with longer pointed beaks.
II.
Windsor Island pollenpeepers where there was little competition with a lush
environment of plentiful seeds, insects and flowers to eat along with fewer
predators. Overtime the fewer seeds were available so the pollenpeepers became
better adapted with longer and sharper beaks to eat the plentiful insects.
III.
Norcross Island pollenpeepers had no competition with a plentiful seed supply
with some insects. They had few predators. Overtime, the lack of predators
allowed three species of pollenpeepers to develop. The blue-headed pollenpeepers
developed long curved beaks and live in the dense forest of the plateau. Another
species of classic pollenpeepers thrives in the open meadow. The third species of
classic pollenpeeper lives along the coastline.
IV.
Warwick Archipelago pollenpeepers found no competition with an environment
of half the island being a lush wet habitat and the other half being desert-like.
Again, seeds were plentiful with some insects and few predators. Overtime, the
pollenpeepers developed into four different species and spread to live on all of the
islands of the Archipelago. By becoming specialized for each distinct
environment, the pollenpeepers have reduced the level of competition.
Lowland Pollenpeeper lives on the western most island and is an insect eater.
These peepers have long sharp beaks. Two species of pollenpeepers live on
the largest island. The High Alpine Pollenpeeper feeds on the nectar found in
the flowers with its long narrow and curved beak. The Coastal Pollenpeeper
is a seed eater and has maintained the original short and wide beak. This type
of pollenpeeper is also found on the next largest island as well. The eastern
most islands are home to the Desert Pollenpeeper another seed eater with a
parrot like short and wide beak.
Part IV: Got Germ X?
Web Address: http://tinyurl.com/GotGermX
Sometimes genetic variation increases the chance of survival for one species at the expense
of another. Read this abstract (a summary) of an article and answer the questions.
1. Through the process of natural selection, and extensive use of antibiotics, bacteria are becoming
stronger.
2. What is another product people may misuse to increase bacterial resistance? Think: what else do we
use frequently that kills bacteria? Lysol, antibacterial soap, Clorox Wipes, Purell (hand sanitizers), etc
3. Describe how natural selection is occurring in these bacteria.
Natural selection allows bacteria with immunity to antibiotics to survive and then reproduce…
eventually creating a population of resistant bacteria that can survive the use of anti-bacterial
products .
Part V: Artificial Selection
Web Address: http://www.learner.org/courses/essential/life/session5/closer1.html
Sometimes people decide what genes get passed on in certain organisms. We call this artificial
selection, or selective breeding.
1. What plant is said to be the ancestor of corn? Teosinte
2. List two other examples of crops that humans have “domesticated”.
Wheat, soybeans, cabbage, broccoli, cauliflower, Brussel sprouts, collards, and/or kale
3. What is the downside to artificial selection? The process removes variation from a population
which can leave selectively bred organisms susceptible to disease and to be less able to
adapt to changes in an environment.
Part VI: Cloning
Web Address: http://learn.genetics.utah.edu/content/tech/cloning/whatiscloning/
Modern genetics also allows for entire organisms to be duplicated or cloned.
1. What is cloning? creation of an organism that is an exact genetic copy of another
2. Compare and contrast identical twins: naturally created vs artificial embryo twinning.
Compare: Both begin with a fertilized egg that divides into a two-celled embryo and the two cells
separate. Each cell continues dividing on its own, ultimately developing into two separate
individuals with identical DNA.
Contrast: Identical twins are created naturally inside a mother’s womb, while AET occurs in a petri
dish
3. Compare and contrast: SCNT vs natural reproduction.
Compare: Both result in an embryo that develops into an organism inside
Contrast: In natural reproduction, the sperm and egg both contain one set of chromosomes.
When the sperm and egg join, the resulting zygote ends up with two sets - one from the father
(sperm) and one from the mother (egg).
In SCNT, the egg cell's single set of chromosomes is removed. It is replaced by the nucleus from a
somatic cell, which already contains two complete sets of chromosomes. Therefore, in the
resulting embryo, both sets of chromosomes come from the somatic cell.
Part VII: Genetic Engineering
Web Address: http://learn.genetics.utah.edu/archive/gmfoods/
1. What is gene transfer technology? A desired gene is identified in the native organism's genome,
cut out, and transferred to the target plant and pasted into its genome. The plant can be bred to
create a new strain that passes the gene from generation to generation.
2. What are the concerns associated with using GTT to genetically modify plants?
a. Cross breeding- preventing genetically-modified versions from mixing with the naturally
existing populations of plants from which they're derived
b. Allergies- There is concern that the protein products of introduced genes may be toxic or
allergenic to certain individuals.
3. Why is genetic engineering (using GTT) compared to selective breeding? (how are they alike)
In both, humans choose and control the desired traits that are to be passed down from one
generation to another. Unlike natural selection, where desired traits are based upon their ability
to provide an advantage to survive and reproduce in an environment.