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Complete the self-assessment rubric before submitting.
You should complete the reader ‘Evolution and Darwin’ before this Essential Biology worksheet.
1. Define evolution.
“Evolution is the cumulative change in the heritable characteristics of a population” (1 p. 37)
2. Populations tend to produce more offspring than the environment can support.
a. Explain how the following lead to a ‘struggle for survival’
· Competition for food
Competition for food can lead to a struggle for survival because the stronger organisms will find the food first and would be able to fight more for it which would then cause the weaker animals to be left with little to no food and also they may get killed for the food because they are not strong enough.
· Competition for mates
Competition for mates can lead to struggle for survival because some organisms can fight when mating which can lead to death and when selecting their mate they can fight with other organisms. This can also lead to struggle for survival because they will fight to provide for their offspring and also the offspring can be killed if the mother of the organism finds another mate.
· Competition for space
Competition for space can lead to struggle for survival because when organisms fight for their living space/shelter this can cause death and the stronger organisms are more likely to win causing the weaker ones to become more week and possibly die.
· Parasitism
Parasitism can lead to struggle for survival because organisms survive off of each other which would mean that the organism that it is feeding from would struggle to survive because it would be weaker and the other organism would be invading its space etc.
· Disease
Disease can lead to struggle for survival because when one organism passes on a disease because it is contagious then it could possible wipe out a whole species which would mean that the particular species would struggle to survive.
· Predation
Predation can lead to struggle for survival because it means that when the predator hunts its prey then the organism that is being hunted has to struggle to survive and this can sometimes effect a whole population to decrease due to predation.
b. Explain the significance of variation within a species in relation to survival.
The significance of variation within a species in relation to survival is that when an organism evolves over time it evolves to become better and stronger in its environment which means that the organisms with useless traits will die off eventually and the organisms with useful traits will survive and reproduce to pass on their good traits to their offspring causing the population to increase.
c. Outline how the following aspects of sexual reproduction contribute to variation within a species:
Meiosis – DNA is formed which is a mix of the two parents of the offspring which creates a different mix of the two parents which is unknown.
Random fertilization – This allows for a random mix of traits to be brought together to allow an organism to be stronger and fitter in its environment as well as become better at survival.
Mutation – These occur in some species and these allow the species to produce offspring with different and helpful traits to make them stronger and make their live easier to survive.
d. State which of the above is the main source of variation within genes.
The main source of variation within genes is meiosis.
e. Explain the term descent with modification.
The term descent with modification is an old term that is used for evolution, it means that over time a species will evolve keeping the stronger, better traits and loosing the useless traits.
f. Describe how the struggle for survival lead to natural selection.
The struggle for survival lead to natural selection because the organisms with the stronger and better traits find mates easier in order to pass on these good traits to their offspring.
3. Antibiotic resistance in bacteria is an example of evolution.
- What is Staphylococcus aureus?
Staphylococcus aureus is a bacteria that is generally found on the skin and mucous membranes that also causes pus-producing infections, cellulites and life0threatening sepis.
- Distinguish between MRSA and MSSA.
MRSA is methycillin-resistant and MSSA is methycillin-susceptible. - Use the key terms environmental change, variation, survival, reproduction to annotate this diagram, explaining how antibiotic resistance has evolved.
Original population: The population before antibiotics when there was no resistance to anitbootics.
Source of variation: Certain strands of bacteria became resistant to antibiotics and then there were antibiotics that were introduced in order to ward off bacteria.
Environmental change: This is the restraint strain that is able to reproduce while the other strands die off causing the illness to continue.
Effect on population: This is when the illness continues to have an effect on the population due to the resistant strands that were not affected by the antibiotics.
Selection for: This is when they are selected because they have the gene that is resistant to antibiotics.
Inheritance: this is the resistant gene that is carried on and the strand continues to grow and affect the population until a new antibiotic is introduced.
''...... can we doubt (remembering that many more individuals are born than can possible survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and procreating their kind? On the other hand, we may feel sure that any variation in the least injurious would be rigidly destroyed. This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection' Darwin C. (1859) The Origin of Species
4. Explain one other example of evolution of a species, in response to environmental change.
(Galapagos finches or pepper moths)
Pepper moths evolved over time due to their environment because they needed to be able to camouflage with their environment in order to survive from predators. These moths gained a mutation in their genes that then continued to pass on through their offspring, this was a trait that allowed them to blend in with their surroundings, this meant then that the moths that now blended in were the ones who could survive causing the other colour of these moths to die out and their population slowly decrease due to the fact that their dominant trait had become the blended colour.
5. Research Another reliable source of evidence to support the theory of evolution by natural selection is the fossil record—paleontologists have been uncovering fossilized remains of species from sedimentary rock deposits and using this information to create timelines of changes in the earth and development of species.
- Outline formation of sedimentary rock.
The formation of sedimentary rock is it begins with igneous, metamorphic or sedimentary rock that are exposed at the earths surface, they are change due to weathering (deposition, erosion, lithification, compaction etc).This process can take millions of years and then it begins again to form more rock.
- Describe how the position of a fossil in sedimentary rock give a clue to its position in time.
A fossil in sedimentary rock can give a clue to its position in time based on what layer it is found in in the rock, the further deeper into the rock the longer time ago it was.
- State some other methods used to confirm the age of fossils.
Some other methods used to confirm the age of fossils are: amino-acid dating, adaptive radiation,
6. Homologous structures
- Define homologous
Homologous is when a structure has similar structure to another organism and is closely related due to their ancestors, this same structure may not be exactly the same but looks similar and is basically used for the change in functions. - One of the most obvious examples of homologous structures in animals is the pentadactyl limb.
Define pentadactyl.
Pentadactyl is put together with two greek words, the first being penta which means five and then dactyl which means the arrangement of toes and fingers, which then shows us that pentadactyl means that the organism has five fingers/digits on a limb.
- Homologous structures has evolved through ‘adaptive radiation’. Explain this term. source: http://en.wikipedia.org/wiki/File:Evolution_pl.png
Darwin described structures such as these as having a ‘unity of type’ - although they look different, on closer inspection they share features. In this case, the bones are the same, though differently shaped.
7. Selective breeding of domesticated animals
- State the purpose of selective breeding
Selective breeding is to get a particular trait/traits to create the best genetic genes.
- Describe why selective breeding is also known as artificial selection.
Selective breeding is also known as artificial selection because of survival needs by the organism which means that the organisms with desired traits are not made.
Artificial selection, like natural selection, can work in two ways. State examples of each:
- Selection for-
- Selection against-
ToK AoK: “It’s only a theory.” Explain, using the scientific method, why evolution is described as a theory and why this represents a high level of certainty in science. What is the linguistic confusion that leads some non-scientists to question the validity of evolution as scientific truth?
Evolution cannot be called truth because we only have some evidence and in some peoples minds the truth is not the truth but it is actually a theory. A theory states that somethine is at a high level of certainty but there is no deffinate yes answer due to there not being enough proper evidence.
Works Cited
1. Allott, Andrew. IB Study Guide: Biology for the IB Diploma. s.l.: Oxford University Press, 2007. 978-0-19-915143-1.
Self Assessment:
Essential Biology / AssessmentCriterion / Complete (2) / Partially complete (1) / Self / Teacher
Presentation & Organisation / NA / File names sensible, work complete and well-presented. Sentences are complete and include vocabulary. All command terms highlighted or underlined.
Academic Honesty / NA / Sources cited using mla method, with Works Cited section complete and correct.
Objective 1 understanding / All answers for the following command terms correct: / Most answers for the following command terms correct:
Define Draw Label List Measure State
Objective 2 understanding / All answers for the following command terms correct: / Most answers for the following command terms correct:
Annotate Apply Calculate Describe Distinguish Estimate Identify Outline
Objective3
understanding / All answers for the following command terms correct: / Most answers for the following command terms correct:
Analyse Comment Compare Construct Deduce Derive Design Determine Discuss
Evaluate Explain Predict Show Solve Sketch Suggest
Logic, notation, mathematical working / NA / Answers are presented in a logical and concise manner. SI units used most times, with correct unit symbols and definitions of terms. All mathematical working shown.
Further research / NA / Evidence is apparent of research and reading beyond the textbook and presentations to find correct answers to challenging questions. If any questions are unanswered, this criterion scores zero.
Total (max 10):
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