Quiz Notes BIOL 2
1. What is the Biological Species Concept?
Defines a species as a group of organisms that can interbreed and produce fertile offspring.
2. What is reproductive isolation?
Mechanism that prevents different species from interbreeding, maintaining species boundaries.
3. Give examples of prezygotic barriers.
Habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, gametic isolation.
4. What are postzygotic barriers?
Reduced hybrid viability, reduced hybrid fertility, hybrid breakdown.
5. Define genetic drift.
A random change in allele frequency within a population, often significant in small populations.
6. What is the founder effect?
When a few individuals start a new population, leading to a change in allele frequencies.
7. What is the bottleneck effect?
A population’s size is drastically reduced, affecting genetic diversity and allele frequencies.
8. Explain gene flow.
Movement of alleles between populations, which increases genetic diversity.
9. What is natural selection?
Process where individuals with favorable traits are more likely to survive and reproduce.
10. What is nonadaptive evolution?
Evolutionary changes due to random processes, like genetic drift, that don’t necessarily improve fitness.
11. What is Hardy-Weinberg Equilibrium?
A model where allele frequencies in a population remain constant without evolutionary influences.
12. List the five conditions for Hardy-Weinberg Equilibrium.
No mutations, no natural selection, infinitely large population, no gene flow, random mating.
13. What is a gene pool?
The collection of all alleles in a population.
14. Name three main causes of evolutionary change.
Natural selection, genetic drift, gene flow.
15. What are primate characteristics?
Limber joints, grasping hands and feet, short snout, forward-pointing eyes.
16. Name the three groups of primates.
Lemurs/Lorises/Bush Babies, Tarsiers, Anthropoids (monkeys and apes).
17. What is the "Out of Africa" hypothesis?
Theory that modern humans originated in Africa and migrated to other continents.
18. How does bipedalism differ in humans compared to other primates?
Humans have a downward-facing skull opening for the spinal cord, indicating upright walking.
19. Explain the importance of skin melanin levels.
Darker skin protects against UV-induced folate breakdown, while lighter skin aids vitamin D production in low-UV areas.
20. What are keystone species?
Species that play a critical role in maintaining the structure of an ecosystem (e.g., bison in prairies).
21. Define the water cycle in an ecosystem.
Movement of water through evaporation, precipitation, and flow through aquifers and bodies of water.
22. What is a biome?
A large area defined by its characteristic plant life and climate (e.g., desert, tundra, rainforest).
23. What are the primary biomes?
Terrestrial (e.g., tundra, taiga, grasslands, desert) and aquatic (e.g., marine, freshwater).
24. Explain the ecological concept of niche.
The role and position a species has in its environment, including its interactions with other species.
25. How do different types of distribution patterns appear in populations?
Clumped (resources are uneven), uniform (territorial behavior), and random (resources are spread evenly).
26. Describe exponential vs. logistic growth.
Exponential: rapid, unrestricted growth. Logistic: growth that levels off due to environmental limits.
27. What is carrying capacity?
The maximum population size an environment can support based on resources.
28. How does natural selection act on skin color?
Different UV levels in environments favor different melanin levels for optimal vitamin D and folate balance.
29. What is inbreeding depression?
Reduced biological fitness due to breeding of closely related individuals, increasing harmful recessive alleles.
30. What are density-dependent factors?
Factors like predation or disease that affect population growth relative to population size.
31. Describe density-independent factors.
Environmental factors like weather that affect population size regardless of its density.
32. What is sexual selection?
A form of natural selection where certain traits increase an individual's chance of mating.
33. Define stabilizing selection.
A type of natural selection that favors the average traits, reducing variation in a population.
34. What is directional selection?
Selection that favors one extreme phenotype, causing a shift in a population’s traits over time.
35. Define disruptive selection.
A form of selection that favors both extremes of a phenotype, potentially leading to speciation.
36. What is sympatric speciation?
Speciation that occurs within the same geographic area, often through behavioral or ecological separation.
37. Define allopatric speciation.
Speciation due to a physical barrier that separates a population, leading to isolated evolution.
38. What is adaptive radiation?
A process where one species rapidly evolves into several new species to fill different ecological niches.
39. What are homologous structures?
Traits in different species that are similar due to shared ancestry (e.g., forelimbs of mammals).
40. What are analogous structures?
Traits that are similar due to convergent evolution, not shared ancestry (e.g., wings in bats and insects).
41. Explain coevolution.
The process where two species evolve in response to selective pressures imposed by each other.
42. Define a gene mutation.
A change in the DNA sequence that can lead to new variations within a population.
43. What is the significance of a population bottleneck?
It can lead to reduced genetic diversity, making populations more vulnerable to extinction.
44. Describe the carbon cycle.
Movement of carbon through the atmosphere, organisms, oceans, and soil, essential for life processes.
45. What is ecological succession?
A process where an ecosystem changes over time, often following a disturbance.
46. Define primary succession.
Succession that occurs in a lifeless area with no soil, such as after a volcanic eruption.
47. What is secondary succession?
Succession in an area where soil remains, such as after a fire.
48. Describe mutualism.
A symbiotic relationship where both species benefit (e.g., bees and flowering plants).
49. What is commensalism?
A relationship where one species benefits, and the other is unaffected (e.g., barnacles on whales).
50. Define parasitism.
A symbiotic relationship where one organism benefits at the expense of the host.
51. What is a trophic level?
A position in a food web based on how energy is obtained, such as producers, primary consumers, etc.
52. Explain the concept of biomagnification.
The increase in concentration of toxins as they move up the food chain.
53. What is a pioneer species?
The first species to colonize a barren environment in primary succession.
54. Describe genetic variation.
Differences in DNA among individuals within a population, crucial for evolution.
55. What is the role of mutations in evolution?
Mutations introduce new genetic variations, which can be acted on by natural selection.
56. Define a population in biological terms.
A group of individuals of the same species living in a particular area.
57. What is speciation?
The formation of new and distinct species in the course of evolution.
58. Define phylogeny.
The evolutionary history and relationships among species or groups of species.
59. What is an ecological niche?
The role and position a species has in its environment, including resource use and behavior.
60. Describe convergent evolution.
Evolution of similar traits in unrelated species due to similar environmental pressures.
1. What is a population?
A group of organisms of the same species living together in the same geographic area and capable of breeding with each other.
2. How does an entire population evolve?
When certain traits are favored over others, causing changes in the population over generations.
3. Define fitness.
The relative ability of an organism to survive and reproduce in a specific environment.
4. What is fitness in bacteria?
Low fitness bacteria are highly sensitive to antibiotics, while high fitness bacteria are more resistant.
5. What is MRSA?
Methicillin-Resistant Staphylococcus Aureus, a drug-resistant bacterium that is difficult to treat with antibiotics.
MRSA and Staphylococcus aureus
6. What is Staphylococcus aureus?
A bacterium, also known as "staph." Some strains are harmless, while others cause disease; drug-resistant strains exist.
7. What percentage of the U.S. population has S. aureus and MRSA strains?
Approximately 33% have S. aureus, while about 2% have MRSA strains.
8. How is MRSA transmitted?
Through direct or indirect contact, with higher risks among athletes due to skin contact and contaminated surfaces.
Antibiotics and Bacterial Resistance
9. What is the function of antibiotics?
Antibiotics interfere with essential bacterial cell structures, like cell walls, to inhibit growth or kill bacteria.
10. What are beta-lactams?
Antibiotics that interfere with bacterial cell wall synthesis.
11. Define binary fission.
The asexual reproduction of bacteria where one cell divides into two, with possible DNA changes.
12. How does antibiotic resistance spread?
Through random mutations creating new alleles and gene transfer between bacteria.
Evolutionary Mechanisms and Natural Selection
13. How does natural selection lead to new species?
By favoring beneficial traits, natural selection can gradually lead to the formation of new species.
14. What are adaptations?
Traits that increase an organism’s fitness but are often compromises, not perfect solutions.
15. Why can’t an individual evolve?
Evolution occurs within populations over generations, not within an individual’s lifetime.
16. What is the Hardy-Weinberg principle?
A principle that states evolution will not occur if there is no natural selection, mutation, migration, population change, or random mating.
17. What are the three main causes of evolutionary change?
Natural selection, genetic drift, and gene flow.
Types of Selection
18. What is stabilizing selection?
Selection where intermediate phenotypes are favored over extremes, increasing fitness in a stable environment.
19. What is directional selection?
Selection that shifts the population's traits in one direction, favoring one extreme phenotype.
20. What is disruptive (diversifying) selection?
Selection that favors extreme phenotypes over intermediate ones.
Natural Selection in Bacteria
21. How do antibiotics create strong directional selection in bacteria?
By killing non-resistant bacteria and allowing resistant bacteria to survive and reproduce.
22. What is natural selection?
The process by which organisms better adapted to their environment survive and produce more offspring.
Examples of Natural Selection in Humans
23. Give an example of natural selection in humans: Missing wisdom teeth.
A random mutation causing some individuals not to develop wisdom teeth.
24. Describe lactose intolerance.
A mutation causing decreased lactase production, leading to an inability to digest lactose.
25. Describe high-altitude adaptation in Tibetans.
A mutation allowing more oxygen-transporting hemoglobin to cope with lower oxygen levels.
26. What is Allen’s Rule?
Body shape is longer and skinnier in warm climates to aid heat dissipation.
27. What is Bergmann’s Rule?
Body size is larger in colder climates to conserve body heat.
Natural Selection in Plants
28. How does natural selection affect plants?
Examples include carnivorous plants, cacti, and plants producing toxins to survive in their environments.
Artificial Selection
29. What is artificial selection?
Selection controlled by humans, such as breeding dogs or selecting specific crops.
30. What are the risks of artificial selection?
In animals: increased genetic problems, behavior changes, reduced fertility, and obesity; in plants: disease susceptibility and reduced adaptability.
Evolution of Populations
31. What is a species?
A group of organisms that share features, can mate, and produce viable offspring.
32. What is speciation?
The process where one species splits into two due to evolutionary changes, creating diversity.
33. Who is LUCA?
The Last Universal Common Ancestor of all cellular life, about 3.8 billion years ago.
34. What is microevolution?
Small-scale changes in the gene pool of a population over generations.
35. How does microevolution differ from speciation?
Microevolution involves adaptation within a species, while speciation results in the formation of a new species.