General Biology: Study Guide on Evolution, Diversity, and Ecology

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Characteristics of Living Things: All living organisms share key traits such as organization, metabolism, homeostasis, growth, reproduction, response to stimuli, and adaptation through evolution.
Viruses and Life: Viruses are not considered living because they lack cellular structure, cannot reproduce independently, and do not carry out metabolism.
Steps of the Scientific Method: Observation, hypothesis formation, experimentation, data collection, analysis, and conclusion. Each step is essential for systematic investigation.
Parts of the Scientific Method: Includes control and experimental groups, variables (independent, dependent, controlled), and replication.
Quantitative vs. Qualitative Data: Quantitative data is numerical (e.g., height, mass), while qualitative data is descriptive (e.g., color, texture).

Definition of Evolution: Evolution is the change in the heritable characteristics of biological populations over successive generations.
Natural Selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring.
Historical Contributors: Plato, Aristotle, Lamarck, Darwin, and Wallace contributed to evolutionary theory. Darwin and Wallace independently proposed natural selection as the mechanism of evolution.
Evidence for Evolution: Fossil record, comparative anatomy, embryology, molecular biology, and biogeography all support evolutionary theory.
Raw Material for Evolution: Genetic variation within populations provides the raw material for natural selection to act upon.

Sources of Variation: Mutation, gene flow, genetic drift, and sexual reproduction all contribute to genetic diversity within populations.
Allele Frequency: The proportion of a specific allele among all alleles in a population. Evolution involves changes in allele frequencies over time.
Hardy-Weinberg Principle: Describes a non-evolving population. The equation is used to calculate genotype frequencies, where and are allele frequencies.
Types of Selection: Directional (favors one extreme), stabilizing (favors intermediate), and disruptive (favors both extremes).
Sexual Selection: Selection for traits that increase mating success, including intersexual (mate choice) and intrasexual (competition) selection.

Biological Species Concept (BSC): Defines species as groups of interbreeding natural populations that are reproductively isolated from other such groups.
Pre-zygotic and Post-zygotic Barriers: Pre-zygotic barriers prevent mating or fertilization (e.g., temporal, behavioral, mechanical isolation). Post-zygotic barriers occur after fertilization (e.g., hybrid inviability or sterility).
Allopatric vs. Sympatric Speciation: Allopatric speciation occurs due to geographic separation; sympatric speciation occurs without physical barriers, often via polyploidy or ecological differentiation.
Hybrid: An organism resulting from the cross of two different species or populations.

Phylogenetic Trees: Diagrams showing evolutionary relationships among species. Clades are groups consisting of an ancestor and all its descendants.
Homology vs. Analogy: Homologous traits are inherited from a common ancestor; analogous traits arise independently (convergent evolution).
Parsimony: The simplest explanation (fewest evolutionary changes) is preferred when constructing phylogenetic trees.
Fossil Record: Provides evidence for the history of life, mass extinctions, and evolutionary patterns.

Contributions of Carl Woese and George Fox: Identified Archaea as a distinct domain of life based on ribosomal RNA analysis.
Prokaryotic Cell Structure: Lack membrane-bound organelles, have a cell wall, plasma membrane, and often flagella or pili.
Reproduction: Prokaryotes reproduce asexually by binary fission. Genetic diversity is increased by horizontal gene transfer (conjugation, transformation, transduction).

Embryological Development: Key stages include zygote, cleavage, blastula, gastrulation, and organogenesis. Germ layers (ectoderm, mesoderm, endoderm) give rise to different tissues.
Symmetry: Animals may have radial or bilateral symmetry. Bilateral symmetry is associated with cephalization (development of a head region).
Body Cavities: Coelomates have a true body cavity; acoelomates lack one; pseudocoelomates have a body cavity not fully lined by mesoderm.

Major Plant Groups: Nonvascular plants (mosses), seedless vascular plants (ferns), gymnosperms (conifers), and angiosperms (flowering plants).
Adaptations: Evolution of vascular tissue, seeds, and flowers enabled plants to colonize diverse terrestrial environments.

Fungal Structure: Composed of hyphae forming a mycelium; cell walls contain chitin.
Ecological Roles: Decomposers, mutualists (mycorrhizae), and pathogens.

Population Size and Growth: Influenced by birth rates, death rates, immigration, and emigration.
Carrying Capacity (): The maximum population size an environment can sustain.
Growth Models: Exponential growth () and logistic growth () describe population changes over time.
Density-Dependent and Density-Independent Factors: Density-dependent factors (e.g., competition, disease) intensify as population increases; density-independent factors (e.g., weather) affect populations regardless of size.

Types of Interactions: Competition, predation, herbivory, mutualism, commensalism, and parasitism.
Competitive Exclusion Principle: Two species competing for the same resource cannot coexist indefinitely.
Keystone Species: Species with a disproportionately large effect on community structure.
Succession: The process of community change over time, including primary (on new substrates) and secondary (after disturbance) succession.

Energy Flow: Energy enters ecosystems as sunlight, is converted by producers, and flows through consumers and decomposers.
Biogeochemical Cycles: Movement of elements like carbon, nitrogen, and phosphorus through living and nonliving components of ecosystems.
Keeling Curve: Graph showing the rise in atmospheric CO2 concentrations over time, indicating human impact on the carbon cycle.

Carbon Cycle and Climate Change: Human activities (e.g., burning fossil fuels, deforestation) increase greenhouse gases, leading to global warming and climate change.
Adaptation and Mitigation: Strategies to cope with and reduce the effects of climate change, such as renewable energy and conservation.
Eutrophication: Excess nutrients in water bodies cause algal blooms, leading to oxygen depletion and 'dead zones.'