Evolution & Classification

Lamarck's Theory of Evolution

Proposed that organisms change over time to better adapt to their environment.

Inheritance of Acquired Characteristics

Traits developed during an organism's lifetime could be passed to offspring.

Example of Inheritance of Acquired Characteristics

Giraffes stretching their necks to reach leaves → longer necks passed to offspring.

Flaw in Lamarck's Theory

No evidence for inheritance of acquired traits; modern genetics shows DNA is unchanged by use/disuse.

Darwin's Theory of Natural Selection

Organisms produce more offspring than can survive.

Variation in Natural Selection

Individuals in a population differ in traits.

Struggle for Existence

More offspring than resources → competition.

Survival of the Fittest

Individuals with advantageous traits survive and reproduce more.

Adaptation in Natural Selection

Over time, favorable traits become more common in the population.

Evidence for Natural Selection

Fossil records, biogeography, comparative anatomy, embryology.

Addison's Disease

Hormone deficiency (cortisol/aldosterone) → symptoms like fatigue, low blood pressure, hyperpigmentation.

Antibiotic Resistance

Bacteria evolve resistance via natural selection; antibiotics kill susceptible bacteria, resistant ones survive and reproduce.

DNA Structure

Double helix, sugar-phosphate backbone, nitrogenous bases (A-T, G-C).

Genetic Code

4 bases → 64 codons → 20 amino acids.

Transcription/Translation

DNA → mRNA → protein.

Enzymes

Biological catalysts; specificity and efficiency.

Fossils

Preserved remains/traces of ancient organisms.

Types of Fossils

Body fossils, trace fossils, index fossils.

Classification

Science of naming and classifying organisms.

Hierarchy

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

Binomial Nomenclature

Two-part Latinized name (Genus + species).

Linnaeus

Developed modern classification system.

Dichotomous Key

Tool to identify organisms by making a series of binary choices.

Relatedness

Species share more recent common ancestors → more similar DNA/morphology.

Phylogenetic trees

Show evolutionary relationships.

Fossil Record

Shows changes in species over time.

Biogeography

Related species are found in geographically close areas.

Comparative Anatomy

Homologous structures (shared ancestry) vs. analogous (convergent evolution).

Embryology

Similar early developmental stages in related species.

Molecular Biology

DNA/protein similarities indicate common ancestry.