Semester 2 Final

Chapter 9 - Cell Growth/Mitosis
Section 9.1 - Cellular Growth

9. 1. 1 Explain what happens to an organism’s cells when it grows.

   • When organisms grow, their cells increase in number through cell division (mitosis in eukaryotic cells). This allows tissues and organs to increase in size.

10. 1. 2 Explain why cells tend to be small.

    • Cells tend to be small due to the surface area-to-volume ratio. As a cell increases in size, its volume increases faster than its surface area. Smaller cells can more efficiently transport nutrients and waste across the cell membrane.

11. 1. 3 Describe the three main stages of the cell cycle and their main events.

    • The three main stages of the cell cycle are:

      1. Interphase: The cell grows, replicates its DNA, and prepares for division.

         • G1 phase: Cell growth and normal metabolic functions.

         • S phase: DNA replication occurs.

         • G2 phase: Further growth and preparation for mitosis.

      2. Mitosis: The cell divides its nucleus.

         • Prophase: Chromosomes condense and become visible, the nuclear envelope breaks down, and the spindle fibers form.

         • Metaphase: Chromosomes line up along the metaphase plate, and spindle fibers attach to the centromeres.

         • Anaphase: Sister chromatids separate and move to opposite poles of the cell.

         • Telophase: Chromosomes decondense, the nuclear envelope reforms, and the spindle fibers disappear.

      3. Cytokinesis: The cell divides its cytoplasm, resulting in two identical daughter cells.

12. 1. 4 Describe the composition of chromosomes, and differentiate chromosomes and chromatin.

    • Chromosomes are composed of DNA tightly wound around proteins called histones. This condensed structure helps organize and protect the DNA during cell division.

    • Chromatin is the less condensed form of DNA found in the cell during interphase. It consists of DNA strands loosely coiled around histones, allowing for DNA replication and transcription.

Section 9.2 - Mitosis and Cytokinesis

9. 2. 1 Describe the structure of chromosomes.

   • Chromosomes consist of two identical sister chromatids attached at a central region called the centromere. Each chromatid contains a DNA molecule.

10. 2. 2 Describe what happens during each phase of mitosis.

    • Prophase:

      • Chromatin condenses into visible chromosomes.

      • The nuclear envelope breaks down.

      • Spindle fibers form from the centrioles.

    • Metaphase:

      • Chromosomes line up along the metaphase plate (the equator of the cell).

      • Spindle fibers attach to the centromeres of the chromosomes.

    • Anaphase:

      • Sister chromatids separate and move to opposite poles of the cell.

      • The cell elongates.

    • Telophase:

      • Chromosomes arrive at the poles and begin to decondense.

      • The nuclear envelope reforms around each set of chromosomes.

      • Spindle fibers disappear.

11. 2. 3 Identify the phases of mitosis visually.

    • (This requires visual aids, which cannot be provided in this text-based format. Consult a textbook or online resource for diagrams.)

12. 2. 4 Describe the process of cytokinesis

    • Cytokinesis is the division of the cytoplasm, which usually occurs immediately after mitosis. In animal cells, the cell membrane pinches inward, forming a cleavage furrow until the cell is divided into two. In plant cells, a cell plate forms in the middle of the cell and eventually develops into a new cell wall that separates the two daughter cells.

Section 9.3 - Cell Cycle Regulation

13. 3. 1 Explain the role of cyclins in how the cell cycle is regulated.

    • Cyclins are proteins that regulate the cell cycle. They bind to cyclin-dependent kinases (Cdks), activating them and allowing them to phosphorylate target proteins that promote cell division. The levels of different cyclins fluctuate throughout the cell cycle, ensuring that each phase occurs in the proper sequence.

14. 3. 2 Identify the checkpoints that occur during the cell cycle

    • There are several checkpoints during the cell cycle:

      • G1 checkpoint: Checks for DNA damage, cell size, and nutrient availability before entering S phase.

      • S checkpoint: Ensures that DNA replication is proceeding correctly.

      • G2 checkpoint: Checks for DNA damage and ensures that DNA replication is complete before entering mitosis.

      • M checkpoint (Spindle checkpoint): Ensures that all chromosomes are properly attached to the spindle fibers before anaphase.

15. 3. 3 Explain what cancer is and how it is harmful.

    • Cancer is a disease characterized by uncontrolled cell growth and division. It is harmful because cancer cells can invade and damage surrounding tissues, disrupt normal organ function, and spread to other parts of the body (metastasis).

16. 3. 4 Define and identify carcinogens.

    • Carcinogens are substances or agents that can cause cancer. Examples include certain chemicals (e.g., asbestos, benzene), radiation (e.g., UV radiation, X-rays), and viruses (e.g., human papillomavirus).

17. 3. 5 Describe apoptosis, and explain when it occurs.

    • Apoptosis is programmed cell death. It is a normal process that occurs during development and to eliminate damaged or unnecessary cells. Apoptosis occurs when a cell receives signals indicating it should die, such as irreparable DNA damage or during embryonic development to sculpt tissues and organs.

18. 3. 6 Explain what stem cells are.

• Specialized cells with the ability to self renew and differentiate into various cell types

13. 3.7 Differentiate adult and embryonic stem cells

• Adult stem cells are multipotent or unipotent, meaning they can only differentiate into a limited set of cell types within their tissue of origin

• Embryonic stem cells are pluripotent, meaning they can become any cell types within their in the body

Chapter 10 - Sexual Reproduction and Genetics
Section 10.1 - Meiosis

10.1.1 Define homologous chromosomes, diploid and haploid numbers

• Homologous Chromosomes: Pairs of chromosomes that have the same genes in the same order, but may have different alleles (versions of the gene). One chromosome of each pair comes from each parent.

• Diploid: A cell containing two sets of chromosomes (2n). In humans, the diploid number is 46.

• Haploid: A cell containing one set of chromosomes (n). In humans, the haploid number is 23. These are found in gametes (sperm and egg cells).

10.1.2 Identify how many sets of genes are found in most adult organisms.

• Most adult organisms have two sets of genes, one inherited from each parent. This is the diploid condition.

10.1.3 Explain the process of meiosis and describe the events that happen during each phase.

• Meiosis: A type of cell division that reduces the number of chromosomes in a cell by half, producing gametes (sex cells).

  • Meiosis I: Separates homologous chromosomes.

  • Prophase I: Chromosomes condense, and homologous chromosomes pair up, forming tetrads. Crossing over occurs, exchanging genetic material between homologous chromosomes.

  • Metaphase I: Tetrads line up along the metaphase plate. Spindle fibers attach to the centromeres of homologous chromosomes.

  • Anaphase I: Homologous chromosomes separate and move to opposite poles of the cell. Sister chromatids remain attached.

  • Telophase I: Chromosomes arrive at the poles, and the cell divides (cytokinesis), resulting in two haploid daughter cells.

  • Meiosis II: Separates sister chromatids (similar to mitosis).

  • Prophase II: Chromosomes condense.

  • Metaphase II: Chromosomes line up along the metaphase plate. Spindle fibers attach to the centromeres of sister chromatids.

  • Anaphase II: Sister chromatids separate and move to opposite poles of the cell.

  • Telophase II: Chromosomes arrive at the poles, and the cell divides (cytokinesis), resulting in four haploid daughter cells.

10.1. 4 Compare and contrast asexual and sexual reproduction.

• Asexual Reproduction: A single parent produces offspring that are genetically identical to itself.

  • Advantages: Rapid reproduction, no need for a mate.

  • Disadvantages: Lack of genetic variation.

  • Examples: Bacteria (binary fission), some plants (vegetative propagation).

• Sexual Reproduction: Two parents contribute genetic material to produce offspring that are genetically unique.

  • Advantages: Genetic variation.

  • Disadvantages: Requires a mate, slower reproduction.

  • Examples: Most animals and plants.

Section 10.2 - Mendelian Genetics

10.2.1 Describe Mendel’s experiments.

• Gregor Mendel conducted experiments with pea plants to study inheritance. He cross-bred plants with different traits (e.g., flower color, plant height) and analyzed the offspring to determine patterns of inheritance. He concluded that traits are inherited as discrete units (genes) and that some traits are dominant over others.

10.2.2 Explain the basic principles of Mendelian genetics including alleles, dominance and law of segregation.

• Alleles: Different versions of a gene.

• Dominance: When two different alleles are present, the dominant allele is expressed, and the recessive allele is masked.

• Law of Segregation: During gamete formation, the two alleles for each trait separate, so that each gamete carries only one allele for each trait.

10.2.3 Set up and interpret Punnett squares for monohybrid crosses to determine the probability of offspring inheriting various traits.

• A Punnett square is a diagram used to predict the genotypes and phenotypes of offspring from a genetic cross. For a monohybrid cross (involving one trait), a 2x2 Punnett square is used.

• Example: If a heterozygous plant (Bb) is crossed with another heterozygous plant (Bb), the Punnett square would predict the following genotypes: BB, Bb, Bb, bb. The resulting phenotypes would be 3/4 dominant trait and 1/4 recessive trait.

10.2.4 Explain the principle of independent assortment.

• The principle of independent assortment states that the alleles for different traits are inherited independently of each other, assuming that the genes for those traits are located on different chromosomes or are far apart on the same chromosome.

10.2.5Set up and interpret Punnett squares for dihybrid crosses.

• A dihybrid cross involves two traits. A 4x4 Punnett square is used to predict the genotypes and phenotypes of the offspring.

• Example: If two plants are heterozygous for two traits (AaBb), the Punnett square would show the possible combinations of alleles in the offspring.

10.2.6 Explain how sexual reproduction leads to genetic variation.

• Sexual reproduction leads to genetic variation through several mechanisms:

  • Crossing Over: Exchange of genetic material between homologous chromosomes during meiosis.

  • Independent Assortment: Random distribution of chromosomes during meiosis.

  • Random Fertilization: Any sperm can fertilize any egg, leading to different combinations of genes.

Section 10.3 - Gene Linkage and Polyploidy

10.3.1 Explain how the process of meiosis produces genetic recombination

• Meiosis produces genetic recombination through crossing over and independent assortment.

  • Crossing Over: Exchange of genetic material between homologous chromosomes during prophase I of meiosis.

  • Independent Assortment: Random alignment and separation of homologous chromosomes during metaphase I of meiosis.

10.3.2 Explain what is meant by the term gene linkage and how it affects crossing over.

• Gene Linkage: Genes that are located close together on the same chromosome tend to be inherited together. This is because they are less likely to be separated during crossing over.

• The closer the genes are, the lower the chance of crossing over between them.

10.3.3 Define polyploidy and explain why it is important to the field of agriculture

• Polyploidy: A condition in which an organism has more than two sets of chromosomes (e.g., 3n, 4n).

• Importance in Agriculture: Polyploidy can lead to increased size and vigor in plants. Many important crops, such as wheat and potatoes, are polyploid. Polyploidy can also lead to new species formation.

Chapter 11 - Complex Inheritance and Human Heredity
Section 11.1 - Basic Patterns of Human Inheritance

11.1.1 Explain the genotypes of dominant and recessive genetic disorders.

• Dominant Genetic Disorders: Require only one copy of the dominant allele to be present for the disorder to be expressed (e.g., Huntington’s disease).

• Recessive Genetic Disorders: Require two copies of the recessive allele to be present for the disorder to be expressed (e.g., cystic fibrosis, sickle cell anemia).

11.1.2 Identify and describe various recessive and dominant genetic disorders.

• Recessive Genetic Disorders:

  • Cystic Fibrosis: Affects the respiratory and digestive systems due to a defective protein that regulates salt and water movement in cells.

  • Sickle Cell Anemia: Affects red blood cells, causing them to become sickle-shaped and leading to various complications.

  • Phenylketonuria (PKU): Metabolic disorder that can lead to intellectual disability if untreated.

  • Tay-Sachs Disease: Progressive neurological disorder; most common in children of Ashkenazi Jewish descent

• Dominant Genetic Disorders:

  • Huntington’s Disease: Neurodegenerative disorder that affects muscle coordination and leads to cognitive decline.

  • Achondroplasia: Form of dwarfism caused by a mutation in the FGFR3 gene.

11.1.3 Explain the relationship between sickle cell anemia and resistance to malaria.

• Individuals who are heterozygous for the sickle cell allele (i.e., carry one normal allele and one sickle cell allele) are more resistant to malaria. The presence of some sickled red blood cells impairs the malaria parasite’s ability to infect and reproduce within the red blood cells.

11.1.4 Use pedigrees to analyze human inheritance.

• Pedigrees are diagrams that show the inheritance of traits over several generations. They are used to determine whether a trait is dominant or recessive, and whether it is sex-linked or autosomal.

11.1.5 Construct pedigrees from given genetic information.

• Pedigrees:

  • Squares represent males, circles represent females.

  • Shaded symbols indicate individuals with the trait.

  • Horizontal lines connect parents; vertical lines connect parents to offspring.

  • Roman numerals indicate generations; Arabic numerals indicate individuals within a generation.

Section 11.2 - Complex Patterns of Inheritance

11.2.1 Compare and contrast complete dominance with Incomplete dominance and codominance.

• Complete Dominance: One allele completely masks the expression of the other allele.

• Incomplete Dominance: The heterozygous phenotype is a blend of the two homozygous phenotypes (e.g., red flower crossed with a white flower produces pink flowers).

• Codominance: Both alleles are expressed in the heterozygous phenotype (e.g., blood type AB).

11.2.2 Set up and interpret Punnett squares for incomplete dominance and codominance.

• Incomplete Dominance: If a red flower (RR) is crossed with a white flower (WW), the offspring would be pink (RW).

• Codominance: If a person with blood type A (IAIA) has a child with a person with blood type B (IBIB), the child could have blood type AB (IAIB).

11.2.3 Explain the phenomenon of multiple alleles, and use Punnett squares to predict offspring.

• Multiple Alleles: When a gene has more than two alleles in the population (e.g., human blood type, which has alleles IA, IB, and i).
  11.2.5 Explain how human blood type has multiple alleles.

• Human blood type is determined by the ABO gene, which has three alleles: IA, IB, and i. IA and IB are codominant, and i is recessive. This results in four possible blood types: A (IAIA or IAi), B (IBIB or IBi), AB (IAIB), and O (ii).

11.2.6 Explain sex-linkage, and use Punnett squares to predict offspring.

• Sex-Linkage: Genes that are located on the sex chromosomes (X and Y). Most sex-linked traits are located on the X chromosome.

  • Example: Hemophilia is an X-linked recessive disorder. If a carrier mother (XHXh) has a son with a normal father (XHY), there is a 50% chance the son will have hemophilia (XhY).

11.2.7 Define epistasis, and explain how one gene can mask or modify the expression of another gene.

• Epistasis: When one gene affects the expression of another gene. The gene that masks or modifies the expression of another gene is said to be epistatic.

11.2.8 Explain that polygenic inheritance involves multiple genes contributing to a single trait.

• Polygenic Inheritance: Traits that are determined by multiple genes (e.g., skin color, height).

11.2.9 Provide examples of polygenic traits in humans, such as skin color, height, and eye color.

• Skin Color: Controlled by multiple genes, resulting in a continuous range of skin tones.

• Height: Determined by multiple genes and environmental factors.

• Eye Color: Determined by multiple genes, including those that control the amount and distribution of melanin in the iris.

11.2.10 Identify environmental factors that influence gene expression and phenotypic traits.

• Environmental Factors: Can influence gene expression and phenotypic traits (e.g., nutrition, temperature, exposure to toxins).

11.2.11 Explain how twin studies are used in genetics.

• Twin Studies: Used to study the relative contributions of genetic and environmental factors to phenotypic variation. Monozygotic (identical) twins share 100% of their genes, while dizygotic (fraternal) twins share about 50% of their genes.

Section 11.3 - Chromosomes and Human Heredity

11.3.1 Interpret human karyotypes

• Karyotypes: Organized profiles of an individual’s chromosomes. They are used to identify chromosomal abnormalities.

11.3.2 Use a karyotype to identify sex as well as chromosomal disorders

• In a karyotype:

  • Sex is determined by the presence of X and Y chromosomes (XX for female, XY for male).

  • Chromosomal disorders are identified by abnormal chromosome number or structure.

11.3.3 Explain how nondisjunction can affect chromosome numbers.

• Nondisjunction: Failure of chromosomes to separate properly during meiosis, leading to gametes with abnormal chromosome numbers.

11.3.4 Identify the cause of Down syndrome, and explain some characteristics of Down Syndrome.

• Down Syndrome: Caused by trisomy 21 (an extra copy of chromosome 21). Characteristics include intellectual disability, characteristic facial features, and other health problems.

11.3.5 Identify chromosomal disorders in sex chromosomes - Turner’s syndrome, Klinefelter’s.

• Turner Syndrome: Females with only one X chromosome (XO). Characteristics include short stature, infertility, and other health problems.

• Klinefelter Syndrome: Males with an extra X chromosome (XXY). Characteristics include tall stature, reduced fertility, and other health problems.

11.3.6 Explain examples of fetal tests that can be used to determine chromosomal disorders.

• Fetal Tests: Used to detect chromosomal disorders in the fetus:

  • Amniocentesis: A sample of amniotic fluid is taken and analyzed.

  • Chorionic Villus Sampling (CVS): A sample of placental tissue is taken and analyzed.

Chapter 12 - Molecular Genetics
Section 12.1 - DNA: The Genetic Material

12.1.1 Describe the functions of DNA.

• Functions of DNA:

  • Stores genetic information

  • Directs protein synthesis

  • Undergoes replication to pass genetic information to daughter cells

  • Capable of mutation, allowing for genetic variation and evolution

12.1.2 Identify the subunits that make up nucleic acids, DNA and RNA.

• Subunits:

  • Nucleotides: Composed of a sugar (deoxyribose in DNA, ribose in RNA), a phosphate group, and a nitrogenous base.

12.1.3 Describe the double-helix model of DNA, including base pairing.

• Double-Helix Model:

  • DNA consists of two strands wound around each other in a double helix.

  • The sugar-phosphate backbone forms the sides of the helix.

  • Nitrogenous bases (adenine, guanine, cytosine, and thymine) form the rungs of the helix.

  • Base Pairing: Adenine pairs with thymine (A-T), and guanine pairs with cytosine (G-C).

12.1.4 Explain the work of Rosalind Franklin and Watson & Crick in understanding DNA structure.

• Rosalind Franklin: Used X-ray diffraction to produce images of DNA, which provided crucial information about its structure, including its helical shape.

• Watson & Crick: Used Franklin’s data, along with their own, to develop the double-helix model of DNA.

Section 12.2 - Replication of DNA

12.2.1 Describe the process of DNA replication.

• DNA Replication: The process by which DNA is copied.

  • DNA unwinds and separates into two strands.

  • Each strand serves as a template for the synthesis of a new complementary strand.

  • DNA polymerase adds nucleotides to the new strand, following base-pairing rules (A with T, and G with C).

  • Results in two identical DNA molecules.

12.2.2 Compare DNA replication in prokaryotic and eukaryotic cells.

• Prokaryotic Cells: A single origin of replication, and replication occurs in the cytoplasm.

• Eukaryotic Cells: Multiple origins of replication, and replication occurs in the nucleus.

Section 12.3 - DNA, RNA, and Protein

12.3.1 Compare and contrast DNA and RNA structure

• DNA and RNA Differences:

  • Sugar DNA: contains deoxyribose; RNA contains ribose.

  • Bases DNA uses thymine (T); RNA uses uracil (U).

  • Structure DNA is double-stranded; RNA is typically single-stranded.

12.3.2 Explain the role of RNA

• Role of RNA: RNA plays several key roles in gene expression, including:

  • Carrying genetic information from DNA to ribosomes (mRNA).

  • Serving as a structural component of ribosomes (rRNA).

  • Carrying amino acids to the ribosome during translation (tRNA).

12.3.3 Differentiate the three types of RNA

• Three Types of RNA:

  • mRNA (messenger RNA): Carries genetic information from DNA to the ribosomes.

  • rRNA (ribosomal RNA): Forms part of the structure of ribosomes.

  • tRNA (transfer RNA): Carries amino acids to the ribosome during translation.

12.3.4Describe how the cell makes RNA in transcription.

• Transcription:

  • RNA polymerase binds to DNA and separates the strands.

  • RNA polymerase synthesizes a complementary RNA strand, using one strand of DNA as a template.

  • The RNA strand is released, and the DNA strands rejoin.

12.3.5 Explain how the genetic code works, in general.

• Genetic Code: A set of rules that specify the relationship between codons in mRNA and the amino acids in proteins.

12.3.6 Describe the process of translation in terms of codons, anticodons, mRNA, ribosomes, rRNA, and tRNA.

• Translation:

  • mRNA binds to a ribosome.

  • tRNA molecules, each carrying a specific amino acid, bind to the mRNA codons via their anticodons.

  • The ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain.

  • The process continues until a stop codon is reached, and the polypeptide chain is released.

Section 12.4 - Mutation

12.4.1 Define mutation.

• Mutation: A change in the nucleotide sequence of DNA.

12.4.2 Identify and describe the different types of mutations.

• Types of Mutations:

  • Point Mutations: Changes in a single nucleotide base.

  • Substitution: One base is replaced by another.

  • Insertion: An extra base is added.

  • Deletion: A base is removed.

  • Frameshift Mutations: Insertions or deletions that alter the reading frame of the mRNA.

12.4.3 Define mutagen and give examples of mutagens.

• Mutagen:

Chapter 15 - Darwin’s Theory of Evolution
Section 15.1 - Darwin’s Theory of Evolution by Natural Selection

15.1.1 Describe Charles Darwin’s contribution to science

• Charles Darwin is credited with developing the theory of evolution by natural selection. He proposed that species change over time through a process in which individuals with advantageous traits are more likely to survive and reproduce.

15.1.2 Explain how thinkers, including Lyell, Lamarck, and Malthus influenced Charles Darwin.

• Lyell: His work on geology suggested that Earth is very old and changes gradually over time, influencing Darwin's view of gradual evolutionary change.

• Lamarck: Proposed the idea of inheritance of acquired characteristics, which Darwin initially considered but later focused on natural selection.

• Malthus: Argued that populations grow faster than resources, leading to competition and struggle for survival, which influenced Darwin's concept of natural selection.

15.1.3 Explain the process of artificial selection.

• Artificial selection is the process by which humans selectively breed plants and animals for desired traits. This demonstrates that traits can change over time through selective breeding.

15.1.4 Identify and describe the four principles of natural selection - excess production, variation, inheritance, and advantages of certain traits in certain environments (fitness)

• Excess Production: Organisms produce more offspring than can survive.

• Variation: Individuals within a population exhibit variation in their traits.

• Inheritance: Traits are inherited from parents to offspring.

• Advantages of Certain Traits (Fitness): Individuals with advantageous traits are more likely to survive and reproduce in certain environments.

15.1.5 Explain how natural selection can change a population over time.

• Natural selection changes a population over time by increasing the frequency of advantageous traits in the population. Individuals with these traits are more likely to survive and reproduce, passing on their genes to the next generation.

Section 15.2 - Evidence of Evolution

15.2.1 Explain how fossil evidence supports the theory of evolution

• Fossil evidence shows that life on Earth has changed over time. Fossils provide a record of past organisms and their transitions from earlier forms to more recent ones.

15.2.2 Explain how morphology (homologous and vestigial structures) support the theory of evolution

• Homologous Structures: Structures in different species that have a common ancestry, indicating shared evolutionary pathways.

• Vestigial Structures: Structures that have lost their original function over time, providing evidence of evolutionary change from ancestral forms.

15.2.3 Explain how comparative embryology supports the theory of evolution

• Comparative embryology reveals similarities in the development of different species, suggesting common ancestry and evolutionary relationships.

15.2.4 Explain how comparative biochemistry supports the theory of evolution

• Comparative biochemistry shows similarities in the molecular biology of different species, such as DNA, RNA, and proteins, suggesting a shared evolutionary history.

15.2.5 Explain how biogeography supports the theory of evolution

• Biogeography shows that the distribution of species is influenced by geographic factors and evolutionary history. Species in the same geographic region often share common ancestry.

15.2.6 Describe ‘fitness’ in terms of the connection between an organism’s environment and the way it survives.

• Fitness refers to an organism's ability to survive and reproduce in its environment. It is determined by the interaction between the organism's traits and the environmental conditions.

15.2.7 Explain how natural selection gives rise to features that increase reproductive success - including fitness, camouflage, mimicry, and antimicrobial resistance.

• Natural selection gives rise to features that increase reproductive success by selecting for traits that enhance survival and reproduction. These traits can include:

• Fitness: Traits that improve an organism's ability to survive and reproduce.

• Camouflage: Traits that allow an organism to blend in with its environment, increasing its chances of survival.

• Mimicry: Traits that allow an organism to imitate another species, gaining protection or access to resources.

• Antimicrobial Resistance: Traits that enable bacteria to resist the effects of antibiotics, increasing their survival in the presence of these drugs.

Section 15.3 - Shaping Evolutionary Theory

15.3.1 Describe how evolution occurs at the population level, with genes as the raw material.

• Evolution occurs at the population level through changes in gene frequencies over time. Genes are the raw material for evolutionary change.

15.3.2 Explain the concept of genetic equilibrium

• Genetic equilibrium is the state in which the frequencies of alleles in a population remain constant over time. This occurs when there are no evolutionary influences acting on the population.

15.3.3 Identify the five conditions of genetic equilibrium.

• The five conditions of genetic equilibrium are:

• No mutations

• Random mating

• No gene flow

• No genetic drift

• No natural selection

15.3.4 Explain the concept of genetic drift.

• Genetic drift is the random change in allele frequencies in a population due to chance events. It is more pronounced in small populations.

15.3.5 Explain extreme examples of genetic drift including founder effect and bottleneck

• Founder Effect: Occurs when a small group of individuals establishes a new population, and the new population has a different allele frequency than the original population.

• Bottleneck Effect: Occurs when a population undergoes a drastic reduction in size, resulting in a loss of genetic diversity.

15.3.6 Identify and describe different types of natural selection - stabilizing, directional, disruptive, and sexual selection.

• Stabilizing Selection: Favors intermediate phenotypes, reducing variation in the population.

• Directional Selection: Favors one extreme phenotype, causing a shift in the population's trait distribution.

• Disruptive Selection: Favors both extreme phenotypes, leading to a bimodal distribution of traits.

• Sexual Selection: Favors traits that increase an individual's chance of mating, even if they reduce survival.

15.3.7 Identify and describe the two types of speciation - allopatric and sympatric.

• Allopatric Speciation: Occurs when populations are geographically separated, leading to reproductive isolation and the formation of new species.

• Sympatric Speciation: Occurs when new species arise within the same geographic area, often due to reproductive isolation mechanisms.