Intro and Phylogeny

Cambrian explosion

A rapid diversification of life that occurred around 541 million years ago, thought to be triggered by increased oxygen levels, ecological interactions, and developmental modularity.

Taxonomy

The science of ordering species into formal groups based on various characteristics.

Nomenclature

The application of scientific names to species and groups, including binomial nomenclature.

Systematics

The study of species and their phylogenetic relationships.

Phylogenetics

The study of evolutionary relationships among species.

Clade

A group of species that share a common ancestor.

Monophyletic

A taxonomic group that includes the most recent ancestor of a group and all its descendants.

Paraphyletic

A taxonomic group that includes the most recent ancestor and some, but not all, of its descendants.

Polyphyletic

A taxonomic group that does not include the most recent common ancestor of its members.

Synapomorphies

Ancestral or derived characteristics shared by a clade.

Molecular clock

An estimate of time since divergence, measuring how long ago two species shared a common ancestor.

Convergent evolution

When unrelated organisms evolve similar features due to adapting to similar environments or challenges.

Divergent evolution

Evolution where related species evolve different characteristics, leading to increased diversity.

Homologous characteristics

Similar traits in different organisms that originated from a common ancestor.

Analogous characteristics

Traits that have similar functions and appearances but evolved separately due to different evolutionary paths.

Maximum parsimony

A principle stating that the simplest tree with the least evolutionary changes is the most likely.

Basal taxon

A group of organisms that diverged early in the evolutionary history of the group.

Primary Endosymbiosis

The process by which a eukaryotic cell engulfs a prokaryotic cell that can perform photosynthesis (e.g., cyanobacteria).

Secondary Endosymbiosis

The process by which a eukaryotic cell engulfs another eukaryotic cell that has previously engulfed a prokaryotic cell.

Anton van Leeuwenhoek

Known as the Father of Microbiology; discovered 'animacules' in pond water.

Charles Darwin

Known for his contributions to evolutionary biology and the theory of natural selection.

Ernst Haeckel

An advocate for the theory of evolution, known for his work in comparative embryology.

Lynn Margulis

Proposed the Endosymbiotic Theory, explaining the origin of eukaryotic cells.

Carl Woese

Recognized for defining the domain Archaea, crucial for modern taxonomy.

Linnaean system

An early method of classification using hierarchical ranks such as species, genus, family, etc.

Comparative morphology

The study of the form and structure of organisms to infer evolutionary relationships.

Comparative embryology

The study of embryonic development across species to understand evolutionary connections.

Comparative cytology

The study of cell structure and function across different organisms for taxonomic purposes.

Comparative biochemistry

The study of biochemical processes and compounds across organisms to draw evolutionary conclusions.