Defining Science and the Scientific Method

Topic 1: Defining Science and the Scientific Method

• Science is a process, not a body of facts.
• The scientific method involves developing hypotheses, testing them, and forming theories.
• A good hypothesis is testable and falsifiable.
• The null hypothesis is a statement of no effect or difference.
• Living things share characteristics such as cellular organization, metabolism, reproduction, etc.
• Prokaryotic cells lack a nucleus and membrane-bound organelles; eukaryotic cells possess both.
• Taxonomy is the science of classifying organisms.
• Linnaeus's system of taxonomy uses hierarchical categories (Kingdom, Phylum, Class, Order, Family, Genus, Species).
• Woese's findings based on rRNA analysis introduced the concept of domains (Bacteria, Archaea, Eukarya) to better reflect evolutionary relationships.
• Genetic sequences help determine phylogenetic relationships in organisms.
• The theory of spontaneous generation (abiogenesis) states that living organisms arise from non-living matter. This was disproven by experiments (Needham, Spallanzani, Pasteur).
• The cell theory (biogenesis) states that living organisms arise from other living organisms.

Topic 2: Data Analysis and Biodiversity

• Data is factual information used for analysis; it can be represented in tables, graphs, and charts.
• Independent and dependent variables are crucial in analyzing data.
• Biodiversity is the variety of life on Earth, measured using different techniques.
• Extinction is the complete disappearance of a species.
• Extinction rates are rising, driven by various factors (habitat loss, pollution, climate change).
• Biodiversity loss can result in ecosystem instability (climate change, loss of services).
• Weather is short-term atmospheric conditions, while climate is long-term patterns.
• Anthropomorphic climate change is the impact of human activities on the global climate.

Topic 3: Cell Reproduction and Genetics

• Asexual reproduction produces genetically identical offspring; sexual reproduction creates genetically diverse offspring.
• Key stages of mitosis and meiosis.
• Key terms for cells (somatic cell, autosome, sex chromosome).
• Basic chromosome structure explained.
• Ploidy refers to the number of chromosome sets in a cell (haploid, diploid, polyploid).
• Meiosis I and II involve chromosome separation with different results in ploidy.
• Homologous chromosomes—chromosomes that code for the same traits.
• Alleles are alternative forms of a gene; gene loci are their specific locations on chromosomes.
• Asexual and sexual reproduction have advantages and disadvantages for species.

Topic 4: Inheritance Patterns and Genetics

• Hypotheses for inheritance (blending, acquired characteristics, particulate).
• Model organisms (e.g., pea plants) are organisms used for genetic studies.
• Key terms (trait, P1 generation, F1 generation, genotype, phenotype, homozygous, heterozygous).
• Monohybrid and dihybrid crosses.
• Principle of segregation; independent assortment.
• Linkage and sex-linked traits.
• Crossing over is a process during meiosis that introduces genetic variation in offspring.
• Genetic maps are used to determine the relative distances between genes.
• Multiple alleles; complete, incomplete, and codominance.
• Pleiotropy, epistasis, discrete and quantitative traits.
• Polygenic expression—several genes affecting a single trait.
• Gametogenesis (oogenesis, spermatogenesis) explains the process of producing gametes.