BIOL 240 Exam 1 Review

BIOL 240 - Exam 1 Study Notes

Section 1: Multiple Choice (45 points)

1. Fossil Record Rodents

   • A rodent is observed unchanged for 10 million years.

   • Suggestive of: Stabilizing selection.

     • Definition: Stabilizing selection keeps the form of a trait stable over time and prevents drastic changes.

2. Transitional Fossil Observation

   • The same form of rodent is replaced by another with a narrower snout and larger front legs.

   • Suggestive of: Punctuated Equilibrium.

     • Definition: Punctuated equilibrium describes evolution as alternating periods of stability followed by rapid changes.

3. Predation Study in Mice

   • Mice show variable coat color. Moderate light brown mice face the highest predation.

   • This is a classic form of: Disruptive selection.

     • Definition: Disruptive selection occurs when extreme phenotypes are favored over an intermediate phenotype. In this case, light and dark mice are favored over medium-colored mice.

4. Reproductive Isolation in Mice

   • White mice prefer white partners, dark mice prefer dark partners, indicating reproductive isolation.

   • This is a form of: Prezygotic isolation.

     • Definition: Prezygotic isolation occurs when mating preferences prevent fertilization from happening between different species.

5. Beetle Coloration Study

   • Dark beetles in the forest, light on the beach, with phenotype based on the environment rather than genetics.

   • Suggests: Plasticity.

     • Definition: Plasticity refers to the ability of an organism to change its phenotype in response to environmental conditions, without changing its genotype.

6. Ladybug Beetles Carapace

   • The protective shell of ladybugs evolved from forewings of other insects.

   • Example of: Homology.

     • Definition: Homology refers to structures derived from a common ancestor but may serve different functions.

7. Warning Coloration in Insects

   • Bright coloration in unrelated poisonous insects as a predator deterrent.

   • Example of: Convergent evolution.

     • Definition: Convergent evolution occurs when different species independently evolve similar traits as adaptations to similar environments or challenges.

8. Evolution Definition

   • Best definition of evolution: Changes in alleles (or allele frequencies) through time.

     • Not solely defined by adaptation but encompasses various mechanisms.

9. Populations on Galapagos Island

   • Stick insects drift to an island, initially same species by the Typological Species Concept.

     • Definition: Classifies species based on morphological similarities.

10. Biological Species Concept for Migration

    • According to the Biological Species Concept, the populations remain the same species after migration.

      • Definition: Species are groups capable of interbreeding and producing fertile offspring.

11. Tree Comparison

    • If two trees diverge identically, they are considered the Same.

    • Divergence pattern is identical.

12. Tree Divergence Consistency

    • Identically diverging tree structures indicate they are Same.

13. Biological Sexual Reproduction

    • Defined as: Production of offspring carrying genes from multiple parents.

    • Emphasizes genetic mixing.

14. Sexual Reproduction Across Organisms

    • Organisms capable of sexual reproduction include: All of the above (eukaryotes, prokaryotes, viruses).

15. Trait Frequency Calculation

    • In a population of 50, 13 are red:

    • Frequency of the red trait = $\frac{13}{50} = 26\%$.

Section 2: True/False (18 points)

16. Monophyletic Groups

    • C, D, and B do NOT form a monophyletic group. False.

17. Monophyletic Group of A, B, C, D

    • A, B, C, and D ARE a monophyletic group. True.

18. Symplesiomorphy and Trait 3

    • Trait 3 is NOT a symplesiomorphy. False.

      • It is a synapomorphy (a trait specific to that clade).

19. Synapomorphy and Clade A+B

    • Trait 3 is NOT a synapomorphy for clade A+B. False.

      • Trait 2 is the actual synapomorphy for clade A+B.

20. Natural Selection vs. Speciation

    • They are NOT the same. False.

21. Context Dependency of Fitness

    • True. True.

    • Fitness varies depending on the environment.

22. Evolution for the Good of Species

    • Evolution does NOT occur for the good of the species. False.

23. Neutral Mutations

    • Some mutations have no effect on fitness. True.

24. Identification of Species

    • It is NOT easy to identify species. False.

25. Preferential Mating and Isolation

    • It's NOT a form of postzygotic isolation. False.

26. Bateman’s Experiment

    • Female fitness increases is NOT correct. False.

27. Haplodiploidy Sex Determination

    • False. Determined by fertilization status of eggs.

Section 3: Short Answer (36 points)

28. Critiques of Natural Selection

    1. “Survival” = Not all fit organisms survive due to various biotic and abiotic factors.

    2. “Better” = Evolution does not necessarily lead to improvements; it may also lead to maladaptive traits.

    3. “Increased Complexity” = Evolution does not always lead to complexity; simpler organisms can be equally fit in their environments.

29. Gradualism vs. Punctuated Equilibrium

    • Gradualism: Evolution occurs slowly and steadily.

    • Punctuated Equilibrium: Evolution consists of long periods of stasis interrupted by rapid bursts of change.

30. Taxonomic Ranks

    • 1. Kingdom

    • 2. Phylum

    • 3. Class

    • 4. Order

    • 5. Family

    • 6. Genus

    • 7. Species

31. Mechanisms of Evolutionary Change

    • 1. Adaptation

    • 2. Genetic drift

    • 3. Migration/Gene flow

    • 4. Mutation

32. Evidence for Evolution

    • 1. Homology

    • 2. Convergent evolution

    • 3. Direct observation

    • 4. Similarity of island species to mainland relatives

    • 5. Molecular evolution

    • 6. Fossils

    • 7. Vestigial structures

33. Requirements for Natural Selection

    • 1. Variation in a trait

    • 2. Heritability of the trait

    • 3. Differential fitness based on the trait

34. Two-Fold Advantage of Asexual vs. Sexual Reproduction

    • A.) In asexual reproduction, 100% of genes are passed to offspring; in sexual reproduction, only 50% are.

    • B.) In asexual populations, all can reproduce, while in sexual ones, about half can.

35. Hypotheses for the Existence of Sex

    • Tangled Bank Hypothesis: Sexual reproduction reduces competition among relatives by producing genetically diverse offspring capable of specialization in different environments.

36. Paradox of Altruism

    • Altruism is paradoxical because genes promoting self-sacrifice for others reduce individual reproductive success.

    • Kin Selection: Explains the paradox by ensuring that sacrificing for relatives can propagate shared alleles, increasing inclusive fitness.

37. Concerns about Cheating

    • Majority answered No regarding concerns about cheating, indicating perceived integrity during the exam.