BIO112 Midterm1 Example 2025

Page 1: Early Development and Genetics

• Sequence of Early Development

  • The overall sequence of early development proceeds as follows:

    • B) Cleavage → Gastrulation → Organogenesis

• Gene Functions in Development

  • Gap genes, segment-polarity genes, and homeotic genes:

    • B) Code for transcription regulatory factors.

• Directors of Embryonic Development

  • Found within unfertilized eggs:

    • A) Cytoplasmic determinants.

• Cleavage Phase

  • During cleavage:

    • B) The number of cells increases while the size of individual cells decreases.

• Plant Embryo Processes

  • Plant embryos do NOT undergo the process of:

    • A) Gastrulation.

• Flowering Plant Reproduction Sequence

  • Correct sequence:

    • A) Meiosis → Pollination → Nuclear Fusion → Formation of embryo and endosperm.

• Evolution by Natural Selection

  • Darwin and Wallace's theory was revolutionary because:

    • A) It dismissed the idea that species are constant and emphasized the importance of variation and change in populations.

Page 2: Comparative Anatomy and Evolution

• Homologous Structures

  • Anatomical structures homologous to bird wing bones:

    • A) Bones in the flipper of a whale.

• Galápagos Finches

  • There are 13 species of finches in the Galápagos, indicating a complex evolutionary history:

    • A) Prediction regarding ground finches:

      • D) Their genomes should be more similar to each other than those of the five tree finch species.

• Fossil Evidence

  • Thrinaxodon fossils suggest:

    • B) Mammals evolved from a reptilian ancestor.

• Crustacean Evolution

  • Crab tails and swimming:

    • D) Vestigial trait.

• Pigweed Resistance

  • Use of triazine herbicide results in:

    • B) Triazine-resistant weeds were more likely to survive and reproduce.

• Parasitic Morphology

  • Observations of simple morphologies in parasites are explained by:

    • C) Simple morphologies convey some advantage in most parasites.

Page 3: Hardy-Weinberg Principle and Fish Populations

• PTC Tasting

  • Phenylthiocarbamide (PTC) tasting in a population:

    • B) 48% heterozygous.

• Hardy-Weinberg Conditions

  • Easiest condition to meet for a biologist studying fish populations:

    • B) Random mating.

• Inbreeding Depression

  • Inbreeding depression does not cause evolution because:

    • C) It does not change the population's allele frequencies.

• Nonrandom Mating Effects

  • In cases of nonrandom mating favoring similar individuals:

    • A) Change and homozygotes will be overrepresented in the population.

• Selection in Marine Iguanas

  • Based on body size and survival:

    • A) Directional selection.

Page 4: Evolutionary Processes and Plant Development

• Adaptive Evolution in Hawaii

  • Evolution influenced by:

    • B) The founder effect.

• Alternation of Generations

  • In the alternation of generations:

    • A) Sporophyte is diploid and produces spores.

• Double Fertilization

  • Correct process in angiosperms:

    • B) One sperm combines with the egg to form the zygote; another sperm combines with the polar nuclei to form endosperm.

• Pollen Tube Production

  • Pollen tubes are produced by:

    • C) Female gametophyte.

Page 5: Genetics and Populations

• Toxin Production in Milkweed

  • Determining Hardy-Weinberg equilibrium based on genotypes:

    • B) No; there are more heterozygotes than expected.

• Evolution Agents in Sea Turtles

  • Agents that can cause evolution include:

    • D) All of the above.

• Body Size and Predation in Iguanas

  • Introduction of cats would likely lead to:

    • D) Decrease in body size; directional selection.

• Gill Raker Length in Whitefish

  • Evolutionary selection based on diet suggests:

    • B) Disruptive selection.

• Bird Populations and Interbreeding

  • Offspring of two bird populations result in intermediates due to:

    • A) Behavioral reproductive isolation.

Page 6: Juniper Species and Speciation

• Isolation in Juniper Species

  • Juniper species kept separate by:

    • B) Gametic isolation.

• Monophyletic Groups

  • Group that forms a monophyletic category:

    • C) D, E, and F.

• Snapping Shrimp and Panama Effect

  • Bridges represent:

    • A) Geographic barriers.

• Sympatric Speciation in Fish

  • Microhabitat facilitates speciation by:

    • C) Limiting gene flow between fish populations.

Page 7: Phylogenetics and Fossil Records

• Estimating Phylogenetic Trees

  • Approach resembles:

    • D) Phylogenetic species concept.

• Fossil Record Utility in Evolution

  • The fossil record helps by:

    • A) Providing a timeline of life on Earth and documenting transitional forms.

• Paleobotanist Climate Estimates

  • Potential bias in paleobotanical estimates is:

    • B) Habitat bias.