Biology Chapter on Evolutionary Theories
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Questions and Answers

Which of these is NOT a characteristic of a scientific theory?

  • It is constantly evolving
  • It is based on facts
  • It is supported by a large body of evidence
  • It is a proven fact (correct)

What is the main difference between a neutral mutation and a beneficial mutation?

  • A neutral mutation has no effect on the organism's survival, while a beneficial mutation increases its survival. (correct)
  • A neutral mutation can be passed onto offspring, while a beneficial mutation cannot.
  • A neutral mutation is always harmful, while a beneficial mutation is always helpful.
  • A neutral mutation is caused by a change in the DNA sequence, while a beneficial mutation is not.

What is the difference between mitosis and meiosis?

  • Mitosis creates four daughter cells, while meiosis creates two.
  • Mitosis is responsible for genetic variation, while meiosis is not.
  • Mitosis is for growth and repair, while meiosis involves cell division during sexual reproduction. (correct)
  • Mitosis is for sexual reproduction, while meiosis is for growth and repair.

What is a karyotype?

<p>A picture of chromosomes arranged in a specific order. (C)</p> Signup and view all the answers

Which of these is NOT a nondisjunction disorder?

<p>Sickle Cell Anemia (C)</p> Signup and view all the answers

What is the primary difference between Lamarck's theory of evolution and Darwin's theory of natural selection?

<p>Lamarck believed in the inheritance of acquired traits, while Darwin believed in natural selection as the driving force. (A)</p> Signup and view all the answers

Why did Buffon find vestigial organs puzzling?

<p>He couldn't understand how they could be used for survival. (A)</p> Signup and view all the answers

What is the flaw in Lamarck's first principle, Use and Disuse?

<p>It's based on the idea that acquired traits can be inherited. (A)</p> Signup and view all the answers

What is the correct name for the process where humans selectively breed plants or animals for desirable traits?

<p>Artificial selection (D)</p> Signup and view all the answers

Which of these is NOT an example of Artificial Selection?

<p>The development of antibiotic-resistant bacteria (A)</p> Signup and view all the answers

Cuvier's theory of catastrophism suggests that:

<p>Species are created and destroyed by catastrophic events. (C)</p> Signup and view all the answers

Which of these scientists is NOT associated with the early development of evolutionary theory?

<p>Gregor Mendel (A)</p> Signup and view all the answers

What is the main difference between Lamarck's theory and Darwin's theory?

<p>Lamarck believed in the use and disuse of organs, while Darwin focused on natural selection (A)</p> Signup and view all the answers

What is the main idea behind the theory of uniformitarianism?

<p>Earth's features were formed by gradual processes over long periods. (A)</p> Signup and view all the answers

Which of these is a correct example of a neutral mutation?

<p>A mutation that changes the color of an insect's eye without affecting its survival. (A)</p> Signup and view all the answers

Which of the following factors is NOT a significant influence on the intensity of UV radiation reaching Earth's surface?

<p>Magnetic field strength (A)</p> Signup and view all the answers

What is the primary function of melanin in human skin?

<p>To absorb UV radiation and protect cells from damage (B)</p> Signup and view all the answers

How does skin reflectance relate to skin color?

<p>Darker skin reflects less visible light, resulting in lower reflectance values. (C)</p> Signup and view all the answers

Why is the inner arm used to measure skin reflectance?

<p>It is less exposed to sunlight, providing a baseline for natural skin pigmentation. (B)</p> Signup and view all the answers

What is the relationship between latitude and skin reflectance?

<p>Skin reflectance increases with increasing latitude. (D)</p> Signup and view all the answers

According to the hypothesis, why did darker skin pigmentation evolve in populations near the equator?

<p>To protect against harmful UV-induced folate degradation. (D)</p> Signup and view all the answers

What is negative selection in the context of skin color evolution?

<p>Selection against traits that decrease melanin production. (C)</p> Signup and view all the answers

Why is skin cancer not considered a primary selective pressure for skin color evolution?

<p>Skin cancer typically develops after reproductive age, having little impact on gene transmission. (C)</p> Signup and view all the answers

What is the significance of the connection between folate levels and UV exposure?

<p>It explains why darker skin is advantageous in high UV regions. (A)</p> Signup and view all the answers

Which of these is NOT a potential consequence of folate deficiency?

<p>Heart disease (A)</p> Signup and view all the answers

What is the UV Index?

<p>A standardized scale that forecasts the intensity of UV radiation at a given time and location. (A)</p> Signup and view all the answers

Why does UV radiation intensity decrease as you move away from the equator towards the poles?

<p>The sun's rays are more oblique and spread out over a larger surface area at higher latitudes. (B)</p> Signup and view all the answers

How did the discovery of the relationship between folate levels and UV exposure refine the hypothesis for skin color evolution?

<p>It provided a more direct link between UV exposure and reproductive success. (C)</p> Signup and view all the answers

What is the key difference between the initial hypothesis for skin color evolution and the revised hypothesis based on folate levels?

<p>The initial hypothesis focused on vitamin D synthesis, while the revised hypothesis focused on folate degradation. (C)</p> Signup and view all the answers

Why is it inaccurate to say that skin cancer was the key driver of skin color evolution?

<p>Skin cancer typically develops after reproductive age, having little impact on gene transmission. (D)</p> Signup and view all the answers

What is the primary force driving adaptive evolution?

<p>Natural selection (D)</p> Signup and view all the answers

What is the main difference between the bottleneck effect and the founder effect?

<p>The bottleneck effect occurs when a population is reduced in size, while the founder effect occurs when a small group isolates itself from a larger population. (D)</p> Signup and view all the answers

Which of the following scenarios is an example of the bottleneck effect?

<p>A large forest fire reduces the size of a population of deer. (D)</p> Signup and view all the answers

Which of the following is NOT a condition that causes evolution to occur?

<p>Large population size (B)</p> Signup and view all the answers

What is the Hardy-Weinberg principle?

<p>A model that describes the conditions under which allele and genotype frequencies remain constant (C)</p> Signup and view all the answers

Which of the following is a prezygotic isolating mechanism?

<p>Behavioral isolation (D)</p> Signup and view all the answers

What is the difference between microevolution and speciation?

<p>Microevolution is the change in allele frequencies within a population, while speciation is the formation of a new species. (A)</p> Signup and view all the answers

Why is low genetic diversity a concern for populations?

<p>It makes populations more susceptible to diseases and environmental change. (C)</p> Signup and view all the answers

Which of these is NOT a condition for Hardy-Weinberg equilibrium?

<p>Mutations (B)</p> Signup and view all the answers

Which of the following is NOT a prezygotic mechanism of reproductive isolation?

<p>Hybrid sterility (C)</p> Signup and view all the answers

What is gene flow?

<p>The movement of genes between populations due to migration. (B)</p> Signup and view all the answers

Which of the following is an example of allopatric speciation?

<p>A population of fish in a lake is separated by a new land barrier, leading to two distinct species. (D)</p> Signup and view all the answers

Which of the following is a key characteristic of a species?

<p>They can interbreed and produce fertile offspring. (C)</p> Signup and view all the answers

Which of the following is NOT a consequence of the founder effect?

<p>Increased rate of evolution. (A)</p> Signup and view all the answers

What is the main difference between prezygotic and postzygotic mechanisms of reproductive isolation?

<p>Prezygotic mechanisms occur before fertilization, while postzygotic mechanisms occur after fertilization. (C)</p> Signup and view all the answers

Which of the following is an example of how natural selection can drive adaptation?

<p>A population of insects evolves resistance to a pesticide. (D)</p> Signup and view all the answers

Which of the following is NOT a characteristic of prokaryotes?

<p>They have a nucleus. (C)</p> Signup and view all the answers

What is the primary function of pili/fimbriae in bacteria?

<p>Attachment to surfaces. (C)</p> Signup and view all the answers

What is the primary mechanism by which bacteria control their pathogenicity?

<p>Quorum sensing (A)</p> Signup and view all the answers

Which type of bacteria has a thicker peptidoglycan layer in its cell wall?

<p>Gram-positive bacteria. (B)</p> Signup and view all the answers

What serious complication can occur due to the overuse of antibiotics?

<p>Development of antibiotic-resistant bacteria (A)</p> Signup and view all the answers

What is the name given to bacteria that can survive in the presence of oxygen but can also thrive without it?

<p>Facultative aerobes. (C)</p> Signup and view all the answers

Which type of bacteria is responsible for the production of methane?

<p>Methanogens. (A)</p> Signup and view all the answers

What role does the squid play in its symbiotic relationship with bioluminescent bacteria?

<p>It provides a habitat and nutrients (D)</p> Signup and view all the answers

Which of the following processes is NOT a form of horizontal gene transfer in bacteria?

<p>Binary fission. (B)</p> Signup and view all the answers

What does quorum sensing in bacteria allow them to do?

<p>Detect population density (C)</p> Signup and view all the answers

What is a significant outcome of the discovery of penicillin?

<p>Reduced death rates from bacterial infections (C)</p> Signup and view all the answers

What is the name given to the process by which bacteria acquire nutrients from carbon-containing organic materials?

<p>Heterotrophy. (A)</p> Signup and view all the answers

Which of the following is NOT a common shape found in bacteria?

<p>Amoeba. (B)</p> Signup and view all the answers

What aspect is crucial for the development of antibiotic resistance in bacteria?

<p>Repeated antibiotic use (A)</p> Signup and view all the answers

What is the main function of the bacterial capsule?

<p>Reducing water loss and resisting high temperatures. (B)</p> Signup and view all the answers

Interspecies communication in bacteria primarily involves which type of signaling molecules?

<p>AI-2 (A)</p> Signup and view all the answers

Which of the following is NOT a positive contribution of bacteria to the environment and human health?

<p>Infectious diseases. (B)</p> Signup and view all the answers

Which symptom is associated with cholera caused by Vibrio cholerae?

<p>Watery diarrhea (C)</p> Signup and view all the answers

What adaptation allows bacteria to communicate during quorum sensing?

<p>Release and detection of signaling molecules (D)</p> Signup and view all the answers

What catastrophic effect did infections have before the invention of antibiotics?

<p>People died from simple scrapes (D)</p> Signup and view all the answers

What is intraspecies communication in bacteria characterized by?

<p>Coordination of behaviors within the same species (D)</p> Signup and view all the answers

What is the primary mechanism by which traditional antibiotics contribute to bacterial death?

<p>Inhibiting cell wall formation (A)</p> Signup and view all the answers

What is the primary purpose of meiosis in sexual reproduction?

<p>To produce haploid gametes (C)</p> Signup and view all the answers

How do new antibiotic approaches aim to combat bacterial infections differently from traditional methods?

<p>By targeting bacterial communication systems instead of killing the bacteria (D)</p> Signup and view all the answers

What illness can be caused by Clostridium tetani?

<p>Tetanus (D)</p> Signup and view all the answers

What role do bacteria play in understanding human biology?

<p>They are ancient organisms that reveal insights into complex processes. (A)</p> Signup and view all the answers

Which term describes the specific location of a gene on a chromosome?

<p>Locus (A)</p> Signup and view all the answers

What bacteria is responsible for Lyme disease?

<p>Borrelia burgdorferi (C)</p> Signup and view all the answers

What outcome did Alexander Fleming's discovery of penicillin have on bacterial diseases?

<p>Greater treatment options (D)</p> Signup and view all the answers

What results from crossing over during Prophase I of meiosis?

<p>Increased genetic variation (B)</p> Signup and view all the answers

What are the characteristics of viruses?

<p>They require a host cell for reproduction. (D)</p> Signup and view all the answers

What distinguishes asexual reproduction from sexual reproduction?

<p>Produces genetically identical offspring (D)</p> Signup and view all the answers

What distinguishes an epidemic from a pandemic?

<p>An epidemic affects a specific region, while a pandemic spreads globally. (B)</p> Signup and view all the answers

Which structures are responsible for carrying genetic information?

<p>Chromosomes (D)</p> Signup and view all the answers

How do bacteriophages infect bacteria?

<p>By injecting their RNA into bacterial cells while remaining outside. (D)</p> Signup and view all the answers

What happens during the lytic cycle of a virus?

<p>The host cell produces viral proteins and assembles new viruses. (D)</p> Signup and view all the answers

How many chromosomes do human somatic cells typically contain?

<p>46 (A)</p> Signup and view all the answers

What is the purpose of vaccines?

<p>To trigger an immune response without causing the disease. (A)</p> Signup and view all the answers

What is the function of genes within DNA?

<p>To encode information for protein synthesis (A)</p> Signup and view all the answers

What challenge do researchers face in developing vaccines for rapidly mutating viruses?

<p>The rapid mutations decrease the effectiveness of existing vaccines. (C)</p> Signup and view all the answers

What is the term for the condition where an organism has too many or too few chromosomes?

<p>Aneuploidy (D)</p> Signup and view all the answers

What are the primary components that corals are made of?

<p>Hard exoskeletons made of calcium carbonate (C), Soft-bodied organisms called polyps (D)</p> Signup and view all the answers

What is lysogeny in the context of viral infections?

<p>The integration of viral DNA into the host's chromosome. (B)</p> Signup and view all the answers

What phase of meiosis results in the formation of haploid daughter cells?

<p>Telophase I (D)</p> Signup and view all the answers

What is one significant role of viruses in ecosystems?

<p>They play a role in controlling host populations. (C)</p> Signup and view all the answers

What is the process called when corals expel their symbiotic zooxanthellae due to stress from warming waters?

<p>Coral bleaching (C)</p> Signup and view all the answers

Which nitrogenous base pairs with Adenine in DNA?

<p>Thymine (A)</p> Signup and view all the answers

How does targeting quorum sensing potentially reduce antibiotic resistance?

<p>By decreasing the selective pressure for bacteria to mutate. (A)</p> Signup and view all the answers

How do zooxanthellae benefit corals in their mutualistic relationship?

<p>By offering energy through photosynthesis (C)</p> Signup and view all the answers

What is a main advantage of sexual reproduction?

<p>Greater genetic variation (A)</p> Signup and view all the answers

What is significant about the mechanism of action for tetracycline antibiotics?

<p>They interfere with the bacterial ribosomes. (B)</p> Signup and view all the answers

Which of the following describes the state of genetic material in all cells of an individual organism?

<p>It is identical across all cells (B)</p> Signup and view all the answers

Which statement accurately describes the impact of rising water temperatures on coral reefs?

<p>Corals may struggle to survive due to energy loss. (B)</p> Signup and view all the answers

What primary event occurs during Anaphase II of meiosis?

<p>Sister chromatids separate (D)</p> Signup and view all the answers

What type of environments do most protists thrive in?

<p>Aquatic environments (B)</p> Signup and view all the answers

What term describes the arrangement of chromosomes during Metaphase I of meiosis?

<p>Random assortment (C)</p> Signup and view all the answers

Which organism is more closely related to elephants than to brown algae?

<p>Amoebas (A)</p> Signup and view all the answers

Why is the classification of Protista considered outdated?

<p>It does not account for genetic and evolutionary relationships. (D)</p> Signup and view all the answers

What occurs during the alternation of generations in multicellular protists?

<p>Alternation between haploid and diploid stages (C)</p> Signup and view all the answers

How do protists reproduce asexually?

<p>Through binary fission (A)</p> Signup and view all the answers

What can higher water temperatures lead to in coral populations?

<p>Higher mortality rates (C)</p> Signup and view all the answers

What is a significant consequence of coral bleaching?

<p>Decreased energy availability for corals (C)</p> Signup and view all the answers

How is the classification of Protista evolving with current scientific advancements?

<p>By using genetic relationships to redefine classifications (D)</p> Signup and view all the answers

What role do gametes play in the sexual reproduction of protists?

<p>They fuse to form a zygote. (B)</p> Signup and view all the answers

What is the primary role of fungi as decomposers in the ecosystem?

<p>They recycle nutrients by breaking down dead organic material. (C)</p> Signup and view all the answers

Which statement correctly describes HIV's impact on the immune system?

<p>HIV attacks white blood cells and prevents the body from fighting infections effectively. (C)</p> Signup and view all the answers

What is the primary mechanism driving the process of evolution, according to Darwin?

<p>Natural selection (C)</p> Signup and view all the answers

Which of the following concepts explains that all species are derived from ancestral species?

<p>Descent with Modification (C)</p> Signup and view all the answers

How does herd immunity function to protect a population from infectious diseases?

<p>It helps prevent the spread of disease by ensuring a substantial portion of the population is immune. (B)</p> Signup and view all the answers

What type of selection occurs when extremes of a trait are favored over intermediate variations?

<p>Disruptive Selection (D)</p> Signup and view all the answers

Which of the following statements about prions is true?

<p>Prions are abnormally shaped proteins that modify normal neural proteins. (C)</p> Signup and view all the answers

What was a significant finding in the 1998 Lancet article by Andrew Wakefield?

<p>It involved a selective recruitment of subjects from an anti-vaccine group. (A)</p> Signup and view all the answers

What is an example of directional selection in the environment?

<p>Birds with longer beaks surviving better in deep flowers (A)</p> Signup and view all the answers

Which characteristic distinguishes fungal cells from plant cells?

<p>Fungal cell walls are made of chitin. (C)</p> Signup and view all the answers

In which type of selection are individuals with average traits favored above extremes?

<p>Stabilizing Selection (B)</p> Signup and view all the answers

What therapeutic approach does gene therapy utilize?

<p>Using viruses to deliver genes or drugs to target cells. (C)</p> Signup and view all the answers

Sexual selection primarily involves which of the following?

<p>Enhanced mating success (C)</p> Signup and view all the answers

How does natural selection contribute to the survival of a species?

<p>By favoring traits that improve reproductive success (C)</p> Signup and view all the answers

How do fungi negatively impact crops?

<p>By causing plant diseases and producing harmful toxins. (B)</p> Signup and view all the answers

What is a characteristic of yeast compared to other fungi?

<p>Yeast is a single-celled and reproduces by budding. (D)</p> Signup and view all the answers

What can result from trait trade-offs in natural selection?

<p>Harmful costs associated with advantageous traits (D)</p> Signup and view all the answers

What concept describes the inheritance of traits in a population over time?

<p>VISTA (C)</p> Signup and view all the answers

What is the mutualistic relationship between mycorrhizal fungi and plants?

<p>Fungi aid in nutrient absorption for plants and receive carbohydrates in return. (D)</p> Signup and view all the answers

Which of the following correctly explains how penicillin functions?

<p>It inhibits the synthesis of the bacterial cell wall. (B)</p> Signup and view all the answers

Which of the following environmental factors might serve as a selective pressure?

<p>Availability of resources (D)</p> Signup and view all the answers

What is a primary reason for the difficulty in developing an HIV vaccine?

<p>The immune system cannot recognize infected cells quickly enough. (A)</p> Signup and view all the answers

In what way do selective pressures impact evolutionary traits?

<p>They determine which traits are inherited (D)</p> Signup and view all the answers

Which is true regarding lichens in relation to fungi and algae/cyanobacteria?

<p>Lichens provide structure while the algae engage in photosynthesis. (B)</p> Signup and view all the answers

What is an example of sexual selection in play?

<p>Larger antlers in male deer for battle (B)</p> Signup and view all the answers

What describes the role of variation in natural selection?

<p>Variation allows for potential adaptations (C)</p> Signup and view all the answers

What is the significance of Alexander Fleming's discovery of penicillin?

<p>It was the first antibiotic discovered by chance. (C)</p> Signup and view all the answers

What is the primary benefit that fungi gain from their symbiotic relationship with plants?

<p>Carbohydrates produced during photosynthesis (A)</p> Signup and view all the answers

Which of the following is NOT a characteristic typically associated with protists?

<p>They are all heterotrophic (A)</p> Signup and view all the answers

Which of these is an example of a parasitic fungus?

<p>Cordyceps (B)</p> Signup and view all the answers

What is the primary role of protists in an ecosystem?

<p>They serve as primary producers (C)</p> Signup and view all the answers

Which of the following is NOT a way that protists are used as a food source?

<p>Used as a primary source of carbohydrates in most diets (A)</p> Signup and view all the answers

What is the estimated percentage of Earth's oxygen that is produced by protists?

<p>50% (D)</p> Signup and view all the answers

What is a potential consequence of climate change on protists in aquatic ecosystems?

<p>Harmful algal blooms (C)</p> Signup and view all the answers

How do some dinoflagellates benefit coral in a symbiotic relationship?

<p>They provide nutrients through photosynthesis (C)</p> Signup and view all the answers

Which of the following is an example of a protist used as a dietary supplement?

<p>Spirulina (D)</p> Signup and view all the answers

Which of the following statements is TRUE about the kingdom Protista?

<p>It's considered a catch-all kingdom for eukaryotes that don't fit in other groups (C)</p> Signup and view all the answers

Which of these is NOT directly consumed as food, but is derived from protists and used in the food industry?

<p>Agar (D)</p> Signup and view all the answers

What is the main reason for the diverse range of characteristics found in protists?

<p>They have a long evolutionary history (B)</p> Signup and view all the answers

Which statement best describes the relationship between fungi and plant roots in a mycorrhizal relationship?

<p>A symbiotic relationship where both organisms mutually benefit (B)</p> Signup and view all the answers

What is the primary reason why protists are considered the simplest eukaryotic organisms?

<p>They are mostly unicellular (B)</p> Signup and view all the answers

What is the primary function of the stalk-like structure produced by Cordyceps after its host dies?

<p>To release spores to infect new insects (D)</p> Signup and view all the answers

Which of the following is NOT a direct effect of climate change on protists in aquatic ecosystems?

<p>Increased predation by fish (C)</p> Signup and view all the answers

What is the main reason why scientists consider the Kingdom Protista a ‘catch all’ kingdom?

<p>There is a lack of consensus about which groups belong in the kingdom (B)</p> Signup and view all the answers

Which of the following statements accurately describes the evolutionary advantage of lighter skin in low-UV regions?

<p>Lighter skin allows for more efficient vitamin D production, which is essential for calcium absorption. (D)</p> Signup and view all the answers

Which of the following groups is at the highest risk for vitamin D deficiency in regions with low UV radiation?

<p>Dark-skinned individuals living in low-UV regions. (A)</p> Signup and view all the answers

What is the primary evolutionary advantage of darker skin near the equator?

<p>Protection against folate degradation from high UV exposure. (D)</p> Signup and view all the answers

Which of the following is NOT a mechanism of evolution as described in the provided text?

<p>Artificial Selection (D)</p> Signup and view all the answers

What is the primary reason for the high prevalence of unique species on remote islands, as explained by the principles of biogeography?

<p>Geographic isolation, preventing gene flow and leading to distinct evolutionary paths. (D)</p> Signup and view all the answers

The presence of pelvic bones in whales, despite their lack of hind limbs, is an example of which evolutionary evidence?

<p>Vestigial Features (A)</p> Signup and view all the answers

Which of the following accurately describes the relationship between folate degradation and vitamin D synthesis in relation to skin color?

<p>Folate degradation is more significant in darker skin, while lighter skin facilitates vitamin D synthesis. (A)</p> Signup and view all the answers

Why are fossils considered strong evidence for evolution?

<p>They provide a visual representation of how organisms have changed over time. (C)</p> Signup and view all the answers

Which of the following is considered the strongest evidence for common ancestry among species?

<p>DNA comparisons (B)</p> Signup and view all the answers

How does genetic drift influence the evolution of a population?

<p>It causes random changes in allele frequencies, especially in smaller populations. (C)</p> Signup and view all the answers

What does the term "analogous features" refer to, as explained within the context of evolution?

<p>Structures with similar functions but different evolutionary origins. (C)</p> Signup and view all the answers

What is the primary factor driving the evolution of skin color across different populations?

<p>The intensity of ultraviolet radiation and its impact on health. (D)</p> Signup and view all the answers

Based on the content provided, what is the main factor contributing to the increase in vitamin D deficiency risk during winter, especially at higher latitudes?

<p>Decreased sunlight exposure due to shorter days and cloud cover. (C)</p> Signup and view all the answers

How does the use of tanning booths affect vitamin D production and folate degradation?

<p>Increases folate degradation while increasing vitamin D production. (C)</p> Signup and view all the answers

What is the most significant consequence of recent migrations in relation to skin color and health?

<p>Increased risk of vitamin D deficiency in darker-skinned individuals living in low-UV regions. (A)</p> Signup and view all the answers

Which of the following best describes the concept of "natural selection" as presented in the text?

<p>The process by which organisms with advantageous traits are more likely to survive and reproduce. (D)</p> Signup and view all the answers

Which of the following is NOT a postzygotic reproductive isolating mechanism?

<p>Habitat Isolation (D)</p> Signup and view all the answers

What is the primary mechanism by which allopatric speciation occurs?

<p>All of the above (D)</p> Signup and view all the answers

Which scenario is an example of geographic splitting due to continental drift?

<p>The separation of species on either side of the Isthmus of Panama (B)</p> Signup and view all the answers

What is the key difference between gradual sympatric speciation and sudden sympatric speciation?

<p>Gradual speciation involves changes in allele frequencies over many generations, while sudden speciation occurs due to a single genetic mutation. (D)</p> Signup and view all the answers

Which of the following events is NOT an example of adaptive radiation?

<p>The evolution of different species of squirrels in Ontario (D)</p> Signup and view all the answers

Which of the following best describes the process of divergent evolution?

<p>Two species evolve different traits due to different environmental pressures (B)</p> Signup and view all the answers

What type of selection is responsible for the diversification of Darwin's finches into different species?

<p>Disruptive Selection (A)</p> Signup and view all the answers

Which of the following is considered a human influence on speciation?

<p>Habitat fragmentation due to urban development (C)</p> Signup and view all the answers

Which of the following best describes the process of hybrid inviability?

<p>A hybrid offspring is unable to survive to reproduce (A)</p> Signup and view all the answers

Which of the following is NOT a potential outcome of polyploidy?

<p>Increased genetic diversity (D)</p> Signup and view all the answers

What is the primary way in which wildlife corridors can influence speciation?

<p>They can increase gene flow between isolated populations (A)</p> Signup and view all the answers

Which of the following is an example of a species that is the result of hybrid infertility?

<p>A mule (A)</p> Signup and view all the answers

What is the role of a niche in adaptive radiation?

<p>It is the role a species plays in its ecosystem (C)</p> Signup and view all the answers

Which of the following is NOT a common mechanism of geographic splitting?

<p>Climate change (C)</p> Signup and view all the answers

Which of these scenarios best illustrates the concept of zygotic mortality?

<p>A male lion mates with a female tiger, resulting in a hybrid offspring that is unable to survive (B)</p> Signup and view all the answers

What is the relationship between speciation and reproductive isolation?

<p>Reproductive isolation is a necessary condition for speciation (C)</p> Signup and view all the answers

Flashcards

Extreme Thermophiles

Prokaryotes that live in extremely hot environments (70-90°C) such as hot springs and hydrothermal vents.

Prokaryotes

Single-celled organisms lacking a nucleus and membrane-bound organelles. They are the smallest and most numerous organisms on Earth.

Conjugation

A process where one bacterial cell transfers a copy of a plasmid to a nearby cell through a pilus, sharing genetic information.

Plasmid

A small loop of DNA found in prokaryotic cells, separate from the main chromosome.

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Transformation

A process where bacterial cells pick up fragments of DNA from their environment, incorporating it into their own genome.

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Cell Wall

The outermost layer of a bacterial cell, providing structural support and protection. Composed of peptidoglycan.

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Heterotrophs

Organisms that obtain nutrients from carbon-containing organic materials found in living organisms or their remains.

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Autotrophs

Organisms that assemble complex carbons from inorganic materials, using photosynthesis or chemosynthesis.

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Binary Fission

A type of cell division in prokaryotes where the cell copies its DNA and divides into two identical daughter cells.

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Mutations

The process of genetic change in bacteria due to errors in DNA replication during rapid reproduction.

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Cholera

A bacterial infection that causes watery diarrhea, vomiting, and muscle cramps. It's spread through contaminated water and food.

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Vibrio cholerae

The bacterium responsible for cholera.

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Diphtheria

A serious bacterial infection that affects the throat, causing a sore throat, fever, and a barking cough.

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Corynebacterium diphtheriae

The bacterium that causes diphtheria.

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Lyme disease

A bacterial infection spread through tick bites, causing joint pain, paralysis of the face, and severe headaches.

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Borrelia burgdorferi

The bacterium that causes Lyme disease.

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Pertussis

A highly contagious bacterial infection that causes a characteristic 'whooping' cough, fever, and vomiting.

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Bordetella pertussis

The bacterium that causes pertussis.

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Rocky Mountain spotted fever

A serious bacterial infection transmitted by ticks, causing fever, nausea, and a characteristic rash.

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Rickettsia rickettsii

The bacterium that causes Rocky Mountain spotted fever.

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Scarlet fever

A bacterial infection that causes a sore throat, fever, and a characteristic red rash.

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Streptococcus pyogenes

The bacterium that causes scarlet fever.

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Tetanus

A serious bacterial infection that causes muscle spasms, stiffness, and lockjaw.

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Clostridium tetani

The bacterium that causes tetanus.

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Antibiotic resistance

The ability of bacteria to survive and reproduce in the presence of antibiotics.

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What is the "new approach to antibiotics"?

A new approach to fighting bacterial infections that focuses on disrupting bacterial communication systems, like quorum sensing, instead of directly killing bacteria.

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What is quorum sensing?

A process used by bacteria to communicate and coordinate their behavior, often leading to the formation of biofilms and the production of toxins.

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What is antibiotic resistance?

The ability of bacteria to resist the effects of antibiotics, making the antibiotics less effective in treating infections.

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Why is learning more about bacteria important for understanding ourselves?

The study of how bacteria communicate and coordinate their activities, potentially offering insights into similar processes in more complex organisms, including humans.

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What are viruses?

Very small, non-living particles that consist of a protein capsule surrounding genetic material (DNA or RNA). They infect host cells to replicate themselves.

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What is an epidemic?

An outbreak of disease that spreads rapidly within a specific region.

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What is a pandemic?

An epidemic that spreads rapidly across multiple countries or continents, affecting a large population.

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What are bacteriophages?

Viruses that infect bacteria.

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What is an infectious cycle?

The process by which a virus enters a host cell, replicates itself, and eventually destroys the cell to release new viruses.

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What is lysogeny?

A dormant state in which viral DNA integrates into the host chromosome.

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What is the lytic cycle?

The active phase of a viral infection where the virus replicates and eventually destroys the host cell.

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What are vaccines?

A weakened form or part of a virus that is used to trigger an immune response without causing infection.

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What is immune memory?

The ability of the immune system to remember a specific virus and quickly respond to it if it is encountered again.

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What are some challenges in developing vaccines?

Factors that make it difficult to develop effective vaccines for certain diseases, such as the rapid mutation of viruses.

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What is HIV?

A retrovirus that targets and destroys white blood cells, compromising the immune system.

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How does HIV replicate?

The process by which the viral RNA of HIV is converted into DNA and integrated into the host cell's genome.

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What are CDT-4 cells?

White blood cells that are essential for fighting infections, targeted by HIV.

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Why is it difficult for the immune system to fight HIV?

The inability of the immune system to effectively respond to HIV due to the virus's rapid replication and mutation.

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What was the Lancet article (1998) about?

A controversial study that linked the MMR vaccine to autism, later retracted due to scientific misconduct.

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What is Herd Immunity?

Protection from infectious diseases achieved when a significant portion of the population is immune.

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What is Gene Therapy?

Using viruses to deliver therapeutic agents or genetic material to target cells.

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What are Prions?

Abnormal proteins that can cause neurodegenerative diseases by altering the shape of normal proteins.

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What are decomposers?

Organisms that break down dead organic matter, recycling nutrients back into the ecosystem.

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What is Mycorrhizal Symbiosis?

A mutualistic relationship between fungi and plant roots, where both organisms benefit.

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What are Lichens?

A symbiotic relationship between fungi and either algae or cyanobacteria, creating a unique organism.

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What are the characteristics of fungi?

Fungi are eukaryotic organisms that lack chlorophyll and are more closely related to animals than to plants.

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Why are fungi important?

Fungi play diverse roles in ecosystems, including decomposition, symbiotic relationships, and food production.

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How was Penicillin discovered?

Alexander Fleming discovered penicillin by observing a mold inhibiting bacterial growth.

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How can fungi negatively affect crops?

Fungi can cause diseases in crops by damaging crops or producing toxins.

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Mycorrhizal Symbiosis

A mutually beneficial relationship where fungi provide water and nutrients to plants, while plants provide carbohydrates to fungi.

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Cordyceps

A parasitic fungus that infects insects, eventually controlling their behavior and killing them.

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Protista

A diverse kingdom of eukaryotic organisms that includes algae, protozoa, and slime molds. They vary widely in structure and function.

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Unicellular Protists

Single-celled organisms that are as complex and complete as multicellular organisms.

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Primary Producers (Protists)

Organisms that produce food through photosynthesis, forming the base of many ecosystems.

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Nutrient Cycling by Protists

Protists decompose organic matter, releasing essential nutrients back into the environment.

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Protists and Habitat Formation

Protists create habitats and shelter for marine organisms, increasing biodiversity.

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Protists and Coral Symbiosis

A symbiotic relationship where dinoflagellates provide energy for coral through photosynthesis.

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Oxygen Production by Protists

Protists are estimated to produce approximately half of the Earth's oxygen through photosynthesis.

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Climate Change's Effect on Protists

Climate change can impact protist distribution, abundance, and ecosystem function, potentially disrupting food webs.

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Coral and Dinoflagellate Symbiosis

A mutually beneficial relationship where dinoflagellates live inside coral, providing them with energy through photosynthesis.

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Coral

Marine invertebrates belonging to the class Anthozoa, known for their hard, calcium carbonate skeletons.

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Spirulina

A type of algae that is consumed as a dietary supplement, often in powder or tablet form.

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Seaweed

Multicellular algae that are widely consumed as food, particularly in Asian cuisine.

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Agar and Carrageenan

Gelling agents and stabilizers derived from red algae, widely used in food products.

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Heredity

The passing of traits from parents to offspring.

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Genetic Material

The material in an organism that stores genetic information.

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Genes

Distinct sequences of genetic information within DNA.

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Locus

The specific location of a gene on a chromosome.

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Nucleotides

The building blocks of DNA, consisting of a phosphate group, a 5-carbon sugar, and a nitrogenous base.

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Sequence

The order of nucleotides in a DNA strand.

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Asexual Reproduction

A type of reproduction where a new individual is produced from a single parent by cell division, resulting in offspring identical to the parent.

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Sexual Reproduction

A type of reproduction where offspring are produced from the fusion of two sex cells, resulting in a genetic makeup different from either parent.

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Mitosis

The process of cell division that ensures the genetic continuity of cells within a multicellular organism, maintaining the specific chromosome number.

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Gamete

A sex cell that contains half the number of chromosomes as a somatic cell.

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Meiosis

The process of cell division that produces gametes, reducing the chromosome number by half.

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Diploid Number

The number of chromosomes present in a somatic cell, which is twice the number of chromosomes in a gamete.

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Haploid Number

The number of chromosomes present in a gamete, which is half the number of chromosomes in a somatic cell.

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Crossing Over

The exchange of parts of non-sister chromatids during prophase I of meiosis, creating new combinations of genetic information.

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Random Assortment

The random alignment of maternal and paternal chromosomes at the metaphase plate during metaphase I of meiosis, leading to numerous possible combinations of chromosomes in the gametes.

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Coral Polyps

Tiny, soft-bodied organisms that live in colonies and form the basis of coral reefs.

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Coral Exoskeleton

A hard, protective outer layer secreted by coral polyps, composed of calcium carbonate. It forms the structural foundation of coral reefs.

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Coral-Zooxanthellae Symbiosis

A symbiotic relationship where both partners benefit. In corals, algae provide food through photosynthesis, and corals offer protection and access to sunlight.

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Coral Bleaching

The process of corals expelling their symbiotic algae due to stress, usually caused by warming water temperatures. Corals lose their vibrant colors and become vulnerable.

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Coral Calcification

The rate at which corals build and maintain their calcium carbonate skeletons. It is crucial for coral reef growth and integrity.

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Sexual Reproduction in Protists

The fusion of gametes (sex cells) in protists, leading to genetic variation.

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Alternation of Generations

A reproductive cycle in multicellular protists where the organism alternates between a haploid (gametophyte) stage and a diploid (sporophyte) stage.

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Transformation in Protists

The process of a protist taking up fragments of DNA from its environment, incorporating it into its own genome.

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Kingdom Protista

A diverse group of eukaryotes traditionally considered a 'catch-all' category for organisms that didn't fit into other kingdoms.

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Amoeba and Elephant Relationship

Amoebas are closer to elephants than to other protists like paramecia and brown algae, due to shared evolutionary history within the Eukarya domain.

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Outdated Classification of Protista

The outdated classification of Protista as a single kingdom is misleading because it doesn't accurately reflect the diverse evolutionary relationships among protists.

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New Classification of Protists

Scientists are moving away from using Protista as a singular category and focusing on classification based on genetic relationships and evolutionary lineage.

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Impact of Warming Waters on Coral Bleaching

Warming water temperatures can cause corals to expel their symbiotic algae, leading to loss of color and vulnerability to stress and disease.

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Monosomy

One chromosome in place of a homologous pair.

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Karyotype

A picture of chromosomes arranged by number, size, and shape.

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Aneuploidy

A change in the number of chromosomes, like having an extra or missing chromosome.

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Chromosomal Aberration

A change in the structure of a chromosome, like a piece being broken or flipped.

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Translocation

When a chromosome breaks and a piece attaches to a different chromosome.

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Nondisjunction

During cell division, chromosomes line up incorrectly causing parts to be missed or duplicated.

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Evolution

A theory explaining the history of life on Earth, where species change over time.

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Artificial Selection

Humans intentionally selecting organisms with desirable traits for breeding.

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Scientific Theory

A well-supported explanation of a natural phenomenon based on evidence and observations.

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Vestigial Organ

A feature or structure that no longer serves a function but is a remnant of a past ancestor.

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Environmental Pressure

The idea that changes in a species' environment drive them to evolve.

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Natural Selection

A process where individuals with traits better suited to their environment are more likely to survive and reproduce.

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Descent with Modification

The idea that all species have descended from a common ancestor and have changed over time through adaptation.

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Directional Selection

The process where individuals with extreme variations of a trait are favoured, leading to a shift in the population's average trait over time.

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Stabilizing Selection

The process where individuals with average traits have the highest survival rate, preserving the existing average trait within the population.

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Disruptive Selection

The process where individuals with extreme variations at both ends of a trait are favored, increasing diversity within the population.

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Sexual Selection

A type of natural selection where traits that increase an individual's mating success are favored, even if those traits could decrease survival.

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Selective Pressures

Environmental or ecological factors that influence which individuals are more likely to survive and reproduce.

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Fitness

The ability of an organism to reproduce successfully, often related to its adaptation to the environment.

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Heritable Traits

Traits that are inherited from parents to offspring.

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Trait

Any feature or characteristic of an organism, influenced by both genetics and environment.

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Trait Trade-Off

A situation where gaining one advantageous trait comes with a disadvantageous consequence, leading to a potential trade-off in overall fitness.

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Gene Pool

The sum of all genes present in a population at a given time.

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Genetic Drift

The process of change in the frequency of alleles (gene variants) within a population over time.

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Genetic Variation

Differences in genetic makeup among individuals within a population.

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What is UV radiation?

UV radiation is a type of electromagnetic radiation emitted by the sun, with shorter wavelengths and higher energy than visible light. It has beneficial effects on human health, such as vitamin D production, but it also has harmful effects, such as DNA damage and skin cancer.

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What is melanin?

Melanin is a pigment found in the top layer of human skin that absorbs UV radiation, acting as a shield against its damaging effects.

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What is skin reflectance?

Skin reflectance is a measure of how much visible light is reflected back from the skin. Darker skin reflects less light, indicating higher melanin levels.

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What is the UV Index?

The UV Index is a standardized scale used to forecast the intensity of UV radiation at different locations and times. Higher values indicate more intense radiation.

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Why is UV radiation more intense near the equator?

UV radiation intensity is highest near the equator because the sun's rays strike Earth more directly there, resulting in a higher concentration of UV energy. As latitude increases, the rays become more oblique and spread out, reducing intensity.

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What is the hypothesis for skin pigmentation distribution?

The hypothesis suggests that darker skin pigmentation (higher melanin) evolved in populations near the equator to protect against intense UV radiation and its harmful effects, while lighter skin evolved in populations farther from the equator to facilitate vitamin D synthesis under lower UV conditions.

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What is folate and why is it important?

Folate, also known as folic acid, is an essential vitamin vital for cell division and growth. UV radiation can degrade folate, leading to birth defects and other health problems.

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What is negative selection in the context of skin color?

Negative selection against light skin in equatorial Africa means that traits that reduce melanin production (leading to lighter skin) are disadvantageous due to the increased risk of UV-induced folate degradation, impacting reproductive success.

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Why was skin cancer not a key driver of skin color evolution?

Skin cancer, while a serious health concern, is less likely to be a primary driver of skin color evolution because it typically develops after reproductive age, having little effect on the transmission of genes to the next generation.

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What is the revised hypothesis for skin color evolution?

The revised hypothesis suggests that folate protection is a stronger explanation for the evolution of darker skin in high UV regions. Folate degradation, which can lead to birth defects, directly impacts reproductive success.

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How do folate levels relate to UV exposure?

The graph demonstrates that individuals exposed to high UV light levels have significantly lower folate levels compared to those who are not exposed. This finding links UV exposure to folate levels.

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Why are folate levels significant?

Folate deficiency can lead to severe birth defects like spina bifida, affecting reproductive success. This connection between folate and UV exposure highlights the evolutionary advantage of darker skin in high UV regions, as it protects folate levels and promotes healthier offspring.

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How does natural selection explain variation in human skin color?

The theory of natural selection explains the variation in human skin color, proposing that individuals with skin pigmentations best suited to their environment had a higher chance of survival and reproduction, passing on those advantageous traits to their offspring.

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What are the implications of the study of human skin color evolution?

The study of human skin color evolution provides insights into the complex interplay between environmental factors, genetic variation, and human adaptation. The findings highlight the power of natural selection in shaping biological traits.

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What is the significance of skin color variation?

The diverse range of human skin colors serves as a testament to the adaptability of our species, demonstrating how populations have evolved to thrive in various environments across the globe.

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Postzygotic Mechanisms

Reproductive isolating mechanisms that prevent a fertilized egg from growing into a viable and fertile adult.

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Zygotic Mortality

Mating and fertilization are possible, but genetic differences result in a zygote that is unable to develop properly.

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Hybrid Inviability

A hybrid individual develops but either dies before birth or, if born alive, cannot survive to reproduce.

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Hybrid Infertility

Hybrid offspring remain healthy and viable but are sterile. (e.g., mules)

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Allopatric Speciation

The formation of a new species as a result of evolutionary changes following a period of geographic separation. New species often form when a single species is separated into two geographically isolated populations.

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Isolated Islands

Populations may become isolated on islands far from the original population (e.g., Galapagos finches).

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Mountain Ranges

May form, separating populations of species that do not travel over mountains.

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Continental Drift

Can split apart entire continents and separate species into distinct populations (e.g., the Isthmus of Panama).

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Sympatric Speciation

Occurs when individuals within a population become genetically isolated from the parent population, gradually or suddenly.

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Gradual Sympatric Speciation

Species diverge slowly over time in small steps (e.g., the North American apple maggot fly).

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Sudden Sympatric Speciation

A single mutation can render an individual unable to reproduce with other members of the population.

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Polyploidy

Mutations causing polyploidy increase the number of chromosomes in an individual. Polyploids produce fertile offspring when mated with each other but sterile offspring when mated with the original species.

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Human Influence on Speciation

Human activity can influence speciation by: Habitat fragmentation: Highways and urban development can separate habitats, isolating populations. Wildlife corridors: Can prevent isolation by connecting habitats, increasing gene flow and maintaining genetic diversity.

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Adaptive Radiation

Occurs when a single species rapidly evolves into a variety of new, closely related species. Each new species fills an ecological niche.

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Divergent Evolution

Divergent evolution is when two or more separate species evolve differently from a common ancestor. When a single species is placed under different selective pressures, it is likely to undergo divergent evolution. Over time, the two species become more distinct.

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Folate Protection Hypothesis

A theory explaining how darker skin evolved to protect against folate breakdown in high UV regions due to its importance for reproductive success.

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Vitamin D Synthesis Hypothesis

The theory that lighter skin evolved in low-UV regions to balance folate protection with the need for sufficient vitamin D synthesis.

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Seasonal Variation in Vitamin D Deficiency

The risk of vitamin D deficiency is particularly high in the winter months when UV intensity is lower, especially at higher latitudes.

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Migration and Skin Color Mismatch

A phenomenon where recent migrations have resulted in mismatches between skin pigmentation and UV environments, causing health issues like vitamin D deficiency in darker-skinned individuals living in low-UV regions.

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Biogeography

The study of the distribution of species across geographical areas. It provides insights into how species evolve and disperse over time.

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Homologous Features

Physical structures shared by different species due to a common evolutionary origin, even if they serve different functions.

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Analogous Features

Features that serve similar functions but arise from different evolutionary origins.

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Vestigial Features

Remnants of structures that served a function in ancestral species but are now reduced or non-functional.

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Gene Flow

The process of change in allele frequencies within a population due to the migration of individuals, bringing in new genes.

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Adaptation

The process of organisms evolving to become better suited to their specific environment over time.

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Speciation

The process of species evolving from a common ancestor into unique species due to geographical isolation.

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Fossil Record

The study of fossils and their placement in rock layers, revealing the history of life on Earth.

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Microevolution

A change in allele frequencies within a population over time. Refers to small-scale evolutionary changes that happen within a single species.

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Biological species

A group of organisms that can interbreed with one another under natural conditions and produce fertile offspring. They share a common gene pool.

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Reproductive Isolation

The inability of two species to interbreed successfully, preventing gene flow between them. This can be caused by geographical, behavioral, or physiological barriers.

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Reproductive Isolating Mechanism

Any factor that prevents two species from interbreeding when in the same region. Examples include physical differences, behavioral differences, or differences in breeding time.

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Prezygotic Mechanisms

Reproductive isolating mechanisms that prevent fertilization and zygote formation. Examples include behavioral, temporal, ecological, mechanical, and gametic isolation.

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Behavioral Isolation

Different species use different mating behaviors to find and attract a mate. Example: different frog calls.

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Temporal Isolation

Different species breed at different times of the year. Example: frogs breeding in different seasons.

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Ecological Isolation

Very similar species may occupy different habitats within a region. Example: mountain vs. eastern bluebirds.

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Mechanical Isolation

Differences in morphological features cause species to be reproductively incompatible. Example: incompatible genitalia.

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Gametic Isolation

The gametes of different species are not compatible. Example: coral release sperm and eggs, but they cannot fertilize eggs of different species.

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Bottleneck effect

A drastic reduction in population size, leading to a loss of genetic variation. Caused by events like natural disasters. Example: cheetahs, northern elephant seals.

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Founder effect

Occurs when a small group of individuals becomes isolated from a larger population and establishes a new population. The new population will not have the same allele frequencies as the original. Example: finches on the Galapagos Islands.

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Hardy-Weinberg Principle

A mathematical model that predicts allele and genotype frequencies for a population that is not evolving. It assumes no selection, large population, no mutations, no gene flow, and random mating.

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Study Notes

UNIT 1: BIODIVERSITY

Intro to Biodiversity

  • Biodiversity encompasses the variety of life on Earth.

Taxonomy

  • Taxonomy is the science of classifying organisms.

Phylogeny

  • Phylogeny describes the evolutionary relationships among organisms.

Prokaryotes

  • Prokaryotes are single-celled organisms.
  • They lack membrane-bound organelles and a nucleus.
  • Domains Eubacteria (bacteria) and Archaea (archaebacteria) are prokaryotes.
  • They are the smallest and most numerous organisms on Earth.
  • Total bacterial mass exceeds that of all animals.
  • 34 trillion bacteria are found on or within the human body, vs 30 trillion human cells.

Domain Eubacteria

  • Prokaryotes have existed for over 3.5 billion years.
  • Eubacteria are the bacteria we most commonly encounter.

Bacterial Structure

  • Pili/Fimbriae: Hair-like structures aiding attachment to surfaces.
  • Cell Wall: Composed of peptidoglycan (amino acids and sugars).
    • Gram-positive: Purple/violet stain, high peptidoglycan content.
    • Gram-negative: Pink stain, lower peptidoglycan, with outer membrane, more antibiotic resistant.
  • Plasma Membrane: The cell's outer boundary.
  • Flagella: Used for movement.
  • Chromosome: Circular DNA in the nucleoid region.
  • Plasmid: Small loops of DNA in addition to the chromosome.
  • Capsule (optional): Sticky layer surrounding some bacteria, reducing water loss, resisting heat, and blocking antibiotics and viruses.

Bacterial Shapes and Arrangements

  • Shapes: Coccus (round), Bacillus (rod-shaped), Spirillum (spiral).
  • Arrangements: Diplo (pairs), Staphylo (clumps), Strepto (chains).

Bacterial Metabolism

  • Autotrophs: Obtain carbon from inorganic sources.
    • Photoautotrophs: Use sunlight for energy (photosynthesis).
    • Chemoautotrophs: Use chemical compounds for energy.
  • Heterotrophs: Obtain carbon from organic sources (living or dead organisms).
  • Aerobic Respiration: Requires oxygen.
  • Anaerobic Fermentation: Does not require oxygen.
  • Bacteria can be obligate aerobes (require oxygen), facultative aerobes (can survive with or without oxygen), or obligate anaerobes (cannot survive with oxygen).

Bacterial Reproduction

  • Reproduce asexually by binary fission (cell divides into two identical daughter cells).
  • Conjugation: Transfer of genetic material (plasmids) between bacteria via a pilus.
  • Transformation: Uptake of loose DNA fragments from the environment.

Domain Archaea

  • Generally distinct from bacteria and eukaryotes.

Archaea Traits

  • Many live in extreme environments.
    • Methanogens: Low oxygen environments, produce methane.
    • Halophiles: High-salt environments.
    • Extreme thermophiles: Extremely high temperatures (70-90°C).
    • Psychrophiles: Extremely cold temperatures (-10 to -20°C).

Bacterial Diseases

  • Some bacteria produce toxins (e.g., botulinum toxin).
  • Others release toxins when decaying.
  • Many cause serious human diseases (e.g., Cholera, Diphtheria, Lyme Disease, Pertussis, Rocky Mountain Spotted Fever, Scarlet Fever, Tetanus).

Antibiotics and Antibiotic Resistance

  • Antibiotics can effectively treat bacterial infections.
  • Overuse of antibiotics leads to antibiotic-resistant bacteria.
  • Resistant strains arise from mutations occurring before exposure to antibiotics.
  • Resistant bacteria multiply quickly, increasing the frequency of resistant strains, affecting effectiveness of antibiotics.

How Bacteria Talk (Quorum Sensing)

  • Bacteria communicate through quorum sensing.
  • They release signaling molecules (autoinducers) whose concentration increases with population density, triggering a response in the bacteria.

Symbiotic Relationships with Bacteria

  • Bacteria and squid: Bioluminescence in squid light organs for camouflage. Bacteria benefit from nutrients and environment, and squid benefit from camouflage.
  • Bacteria and humans: Many beneficial relationships, with some bacteria providing vitamins.

Viruses

  • Viruses are non-living infectious agents.
  • Consist of genetic material (DNA or RNA) enclosed in a protein coat.
  • Some viruses have an envelope.
  • Require a host cell to replicate.
  • Viruses cause various diseases (mild and serious).

Infectious Cycles

  • Viruses invade, replicate, then release from the host cell.
  • Lysogeny: Viral DNA integrates into host DNA; replicates with host DNA.
  • Lytic cycle: Viral DNA separates, replicates, and assembles new viruses inside the host, leading to host cell lysis.

Importance of Viruses

  • Responsible for many diseases.
  • Some contribute to cancer.
  • Play a significant role in ecosystems controlling populations.

Viral Classification

  • Classified by shape, size, and genetic material.
  • Usually infect specific cell types in hosts.

Bacteriophages

  • Viruses that infect bacteria.
  • Injects viral DNA into the bacterial cell.

Vaccines

  • Vaccines use weakened versions or parts of viruses to build immunity for infection.
  • Preventing many diseases, improving population health.

Challenges in Developing Vaccines

  • Viruses evolve rapidly (Ex. Influenza).
  • Some viruses evade the immune system (Ex. HIV).

Fungi

  • Fungi are heterotrophic eukaryotes, using external digestion.
  • Important decomposers.
  • Symbiotic relationships (i.e. lichen, mycorrhizae)
  • Some are parasitic and cause diseases (i.e. Cordyceps).

Protists

  • Protists are eukaryotes, and are a catch all for organisms that don't fit into plant, animal or fungal kingdoms.
  • Most are unicellular, but some are multicellular.
  • Can be autotrophic, heterotrophic or mixotrophic.
  • Live in aquatic and moist terrestrial environments.
  • Important primary producers in many ecosystems, decomposers, and are involved in symbiotic relationships (i.e. coral and algae).

Genetics

Heredity

  • Heredity is the transmission of traits from parents to offspring.
  • Genetic material is stored in DNA.
  • All organisms contain DNA organized into genes.

Genes and DNA

  • Genes are sequences of DNA that encode proteins.
  • DNA is a double helix with nucleotides (adenine, cytosine, guanine, thymine) forming base pairs (A-T, C-G).
  • DNA sequence determines protein function.

Meiosis

  • Meiosis produces haploid gametes (sex cells), reducing the chromosome number by half.
  • Crossing over and random assortment increase genetic variation.
  • Mistakes in meiosis can produce aneuploidy (incorrect chromosome number).
  • Meiosis differs from mitosis used for growth and repair in multicellular organism

Karyotyping

  • Karyotyping is displaying chromosomes for counting and comparison.
  • Used for genetic screening.
  • Sex determination is based on sex chromosomes (X and Y).

Evolution

  • Evolution is the change in gene frequencies within a population over generations.
  • Mechanisms: Natural Selection, Genetic Drift, Mutation, Gene Flow.

Speciation

  • Speciation is the formation of new species.
  • Isolating mechanisms (reproductive) prevent interbreeding between populations:
    • Prezygotic: Prevent zygote formation (e.g., behavioral isolation, temporal isolation)
    • Postzygotic: Prevent the hybrid zygote from developing into a fertile individual (e.g., hybrid inviability).

Natural Selection

  • Traits improving survival and reproduction (fitness) are favored by natural selection.
  • Different types of selection (directional, stabilizing, disruptive, sexual).

Skin Color Evolution

  • Skin color variation is the result of natural selection.
  • UV radiation intensity and folate protection are key drivers.
  • Lighter skin in lower UV regions facilitates vitamin D synthesis.
  • Skin color evolution is an adaptation to environmental factors.

Evidence for Evolution

  • Fossil record, biogeography, homologous features, embryonic development, analogous features, vestigial features, competition within populations, and DNA similarity.

Mechanisms of Evolution

  • Natural selection (the primary driver of adaptive evolution).
  • Genetic drift (random changes in allele frequencies, more impactful in small populations).
  • Gene flow (the movement of genes between populations due to migration).

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Test your knowledge on the major concepts of evolutionary biology with this quiz. Explore the differences between Lamarck's and Darwin's theories, the role of mutations, and key scientific principles. Perfect for students studying biology or evolution.

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