Fundamentals of Biology

• Biology is the scientific study of life
• It encompasses the structure, function, growth, origin, evolution, distribution, and taxonomy of living organisms

Core Principles of Biology

• Cell theory: All living organisms are composed of cells
• Gene theory: Hereditary information is encoded in DNA and passed from parents to offspring
• Homeostasis: Living organisms maintain a stable internal environment
• Evolution: Populations of living organisms change over time through natural selection

Cell Structure and Function

• Cells are the basic units of life
• Eukaryotic cells: Have a nucleus and other membrane-bound organelles
• Prokaryotic cells: Lack a nucleus and other membrane-bound organelles

Genetics

• Genes are the units of heredity
• DNA (deoxyribonucleic acid): The molecule that carries genetic information
• RNA (ribonucleic acid): Involved in protein synthesis
• Mutation: A change in the DNA sequence
• Gene expression: The process by which the information encoded in a gene is used to synthesize a functional gene product

Evolution

• Evolution is the change in the heritable characteristics of biological populations over successive generations
• These characteristics are genes that are passed on from parent to offspring
• Evolution can occur due to a number of mechanisms, including natural selection, mutation, genetic drift, and gene flow

Natural Selection

• Natural selection is a mechanism of evolution
• Individuals with traits better suited to their environment are more likely to survive and reproduce
• These traits are then passed on to their offspring
• Over time, this can lead to changes in the genetic makeup of a population

Evidence for Evolution

• Fossil record: Provides evidence of extinct organisms and the transitions between them
• Comparative anatomy: Similarities in the anatomy of different organisms can indicate common ancestry
• Embryology: Similarities in the development of different organisms can indicate common ancestry
• Molecular biology: Similarities in the DNA and protein sequences of different organisms can indicate common ancestry
• Biogeography: The distribution of organisms on Earth can provide evidence of their evolutionary history

Mechanisms of Evolution

• Mutation: Creates new genetic variation
• Genetic drift: Random changes in the frequency of alleles in a population
• Gene flow: The movement of genes between populations
• Natural selection: Differential survival and reproduction based on heritable traits

Speciation

• Speciation is the process by which new species arise
• Allopatric speciation: Occurs when populations are geographically isolated from each other
• Sympatric speciation: Occurs when populations are not geographically isolated from each other

Phylogeny

• Phylogeny is the evolutionary history of a group of organisms
• Phylogenetic trees are diagrams that depict the evolutionary relationships among organisms

Key Concepts in Evolution

• Adaptation: A trait that increases the survival and reproduction of an organism in its environment
• Fitness: The ability of an organism to survive and reproduce in its environment
• Common descent: The idea that all living organisms share a common ancestor

Levels of Biological Organization

• Molecules
• Cells
• Tissues
• Organs
• Organ systems
• Organisms
• Populations
• Communities
• Ecosystems
• Biosphere

Classification of Life

• The current classification system includes three domains: Bacteria, Archaea, and Eukarya
• Within each domain are kingdoms, phyla, classes, orders, families, genera, and species

Importance of Biology

• Understanding the natural world
• Developing new medicines and technologies
• Addressing environmental problems
• Improving human health

Population Genetics

• Focuses on the genetic variation within populations
• Examines changes in allele frequencies over time
• Hardy-Weinberg principle: Describes the conditions under which allele and genotype frequencies in a population will remain constant from generation to generation (no mutation, random mating, no gene flow, no natural selection, large population size)

Molecular Evolution

• Studies the evolution of DNA, RNA, and proteins
• Uses molecular data to infer evolutionary relationships
• Molecular clock: A technique that uses the rate of mutation to estimate the time of divergence between two lineages

Development and Evolution

• Examines how developmental processes contribute to evolutionary change
• Hox genes: A group of genes that control the body plan of animals
• Changes in the expression of Hox genes can lead to major evolutionary changes

Ecology and Evolution

• Studies the interactions between organisms and their environment
• How these interactions drive evolutionary change
• Coevolution: The process by which two species evolve in response to each other

Human Evolution

• The evolutionary history of humans is traced through fossil records
• Genetic analyses show close relationships with chimpanzees
• Key evolutionary milestones: bipedalism, increased brain size, and language

Evolution of Antibiotic Resistance

• Antibiotic resistance in bacteria is a major public health threat
• Bacteria evolve resistance through natural selection when exposed to antibiotics
• Understanding the mechanisms of resistance is crucial for developing new strategies to combat it

Conservation Biology

• Uses evolutionary principles to conserve biodiversity
• Understands the evolutionary history and genetic diversity of endangered species
• Helps to develop effective conservation plans

Important Figures in Evolution

• Charles Darwin: Developed the theory of evolution by natural selection
• Alfred Russel Wallace: Independently developed the theory of evolution by natural selection
• Gregor Mendel: Discovered the basic principles of heredity