General Biology Exam 1 Study Guide: Evolution, Genetics, and Scientific Skills

Study Guide - Smart Notes

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Biology is the scientific study of life and living organisms. Understanding the foundational concepts and methods is essential for further study.

Characteristics of Living Things: Living organisms share common features such as organization, metabolism, homeostasis, growth, reproduction, response to stimuli, and adaptation through evolution.
Hypothesis and Scientific Theory: A hypothesis is a testable statement that explains an observation. A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of evidence.
Experimental Design: Key concepts include control (a standard for comparison), replication (repeating experiments), variable (independent and dependent), treatment (experimental conditions), and falsifiability (the ability to be proven false).
Biological Hierarchy: Life is organized into a hierarchy: atom → molecule → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere.
Scientific Nomenclature: The system of naming organisms using binomial nomenclature (Genus species), often derived from Latin or Greek roots.

The development of evolutionary theory was influenced by various scientists and historical events.

Darwin and Wallace: Proposed the theory of evolution by natural selection, which was revolutionary because it provided a natural mechanism for evolution.
Predecessors: Aristotle and Plato believed in fixed species; Lamarck proposed inheritance of acquired characteristics.
Catastrophism vs. Uniformitarianism: Catastrophism (Cuvier) suggested sudden events shaped Earth; Uniformitarianism (Lyell) argued for gradual processes.
Special Creation vs. Evolution: Special creation posited that species were created independently; evolution suggests common ancestry.
Lamarck vs. Darwin: Lamarck believed in the inheritance of acquired traits; Darwin proposed natural selection as the mechanism of evolution.
Influential Figures: Erasmus Darwin, James Hutton, Georges Cuvier, Charles Lyell, and others contributed to evolutionary thought.

Fossil Record: Shows succession of forms and evidence for change over time.
Geological Principles: Uniformitarianism and the age of Earth support gradual change.
Direct Observations: Observable evolutionary changes in living populations.
Biogeography: Distribution of species supports common ancestry.
Homology: Similarity due to shared ancestry (e.g., limb bones in vertebrates).
Homoplasy: Similarity due to convergent evolution, not common ancestry.

Natural selection is the primary mechanism of evolution, as described by Darwin and Wallace.

Four Postulates of Natural Selection:
1. Variation exists among individuals in a population.
2. Some of this variation is heritable.
3. More offspring are produced than can survive.
4. Individuals with advantageous traits survive and reproduce more.
Antibiotic Resistance: An example of natural selection in action, where bacteria evolve resistance to antibiotics.
Galápagos Finches: Classic example of adaptive radiation and natural selection.
Misconceptions: Evolution does not have a goal; individuals do not evolve, populations do.
Constraint: Limitations on evolution due to genetic, developmental, or environmental factors.

Genetic variation and mechanisms of inheritance are central to understanding evolution.

Mendelian Genetics: Gregor Mendel's work established the principles of inheritance (dominant and recessive alleles).
Genotype vs. Phenotype: Genotype is the genetic makeup; phenotype is the observable trait.
Hardy-Weinberg Principle: Describes a non-evolving population. The equation is: where and are the frequencies of two alleles.
Evolutionary Mechanisms:
- Genetic Drift: Random changes in allele frequencies, more pronounced in small populations.
- Gene Flow: Movement of alleles between populations.
- Mutation: Source of new genetic variation.
- Natural Selection: Differential survival and reproduction.
Bottleneck Effect: Sharp reduction in population size affects genetic diversity.
Founder Effect: New population started by a small group, leading to different allele frequencies.

Sexual Selection: Selection for traits that increase mating success.
Intersexual Selection: Mate choice (usually female choice).
Intrasexual Selection: Competition among the same sex (usually males).
Batemann-Trivers Hypothesis: Explains differences in reproductive investment and mate choice.
Honest Signals: Traits that reliably indicate fitness.

Speciation is the process by which new species arise.

Species Concepts: Biological, morphological, and phylogenetic species concepts.
Reproductive Isolation: Prezygotic (before fertilization) and postzygotic (after fertilization) barriers.
Allopatric Speciation: Speciation by geographic isolation.
Sympatric Speciation: Speciation without geographic isolation, often via polyploidy or disruptive selection.
Polyploidy: Having more than two sets of chromosomes, common in plants.

Phylogenetic trees depict evolutionary relationships among species.

Parts of a Phylogenetic Tree: Node (common ancestor), branch (lineage), root (ancestral lineage).
Monophyletic Clade: Group containing an ancestor and all its descendants.
Building Trees: Parsimony (simplest explanation), different methods (e.g., maximum likelihood).
Interpreting Trees: Trees can be read with time or genetic change on the axes.
Common Misconceptions: Not all trees show the same information; branch order may not indicate time.

Bioskills 2: Distinguish dependent and independent variables; choose correct graph type; interpret graphs.
Bioskills 3: Understand standard error bars; know what a p-value is; distinguish causation from correlation; use error bars and p-values to interpret data.
Bioskills 4: Apply "Both-And" and "Either-Or" rules for probability.
Bioskills 12: Interpret and create visual models.
Bioskills 13: Read and construct phylogenetic trees; interpret trees with nucleotide change or time on axes.
Bioskills 17: Recognize that biological terms may differ from everyday use (e.g., "theory," "fitness"); identify goal-oriented and human-centered thinking.
Bioskills 18: Use study tools provided in this section.

Mechanism	Effect on Genetic Variation	Directionality	Example
Natural Selection	Can increase or decrease	Non-random	Antibiotic resistance in bacteria
Genetic Drift	Decreases (especially in small populations)	Random	Bottleneck effect in cheetahs
Gene Flow	Increases (introduces new alleles)	Random	Migration between populations
Mutation	Increases (creates new alleles)	Random	Point mutation in DNA

Additional info: Some explanations and examples were expanded for clarity and completeness based on standard General Biology curriculum.