Organizing Diversity and Phylogenetic Trees

Vocabulary flashcards covering phylogeny, endosymbiosis, organismal life cycles, Protista/Archaeplastida concepts, and key terms from the lecture notes.

Phylogenetic tree

A branching diagram showing evolutionary relationships among species or groups based on similarities and differences in traits.

Domains of life

Three fundamental domains: Bacteria, Archaea, and Eukarya.

Endosymbiotic theory

Mitochondria and chloroplasts in eukaryotic cells originated as aerobic bacteria ingested by a larger host cell.

Mitochondria

Organelle responsible for cellular respiration in eukaryotes; evidence for endosymbiosis.

Chloroplasts

Organelle for photosynthesis in plants and algae; evidence for endosymbiosis.

Root (phylogeny)

The ancestral starting point from which all lineages descend.

Tips (phylogeny)

The most recent descendants or current taxa at the ends of branches.

Speciation

Evolutionary event where a lineage splits into two distinct lineages.

Clade

A group consisting of a common ancestor and all its descendants; a monophyletic group.

Monophyletic

A group that includes a common ancestor and all of its descendants.

Paraphyletic

A group that includes a common ancestor but not all of its descendants.

Polyphyletic

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

Homologous characters

Traits inherited from a common ancestor and used to infer relationships.

Shared derived character (synapomorphy)

A trait that evolved in a common ancestor and is present in its descendants, useful for defining clades.

Sporangia

Organs in which spores are produced by meiosis.

Meiosis

Cell division producing haploid gametes or spores with genetic variation.

Mitosis

Cell division resulting in two genetically identical daughter cells.

Gametophyte

Multicellular haploid phase that produces gametes.

Sporophyte

Multicellular diploid phase that produces spores.

Haplodiplontic life cycle

Life cycle with alternating multicellular haploid (gametophyte) and diploid (sporophyte) generations.

Diplontic life cycle

Life cycle where only the diploid phase is multicellular; haploid phase is limited to gametes.

Haplontic life cycle

Life cycle in which the haploid stage is multicellular and the diploid stage is limited to the zygote; zygotic meiosis.

Gametic meiosis

Meiosis directly produces gametes; typical of diplontic organisms like many animals.

Zygotic meiosis

Meiosis occurs after fertilization of the zygote to produce haploid spores; haplontic life cycle.

Protista

A historically defined kingdom that is paraphyletic and not a single evolutionary lineage; includes diverse protists.

Archaeplastida

Supergroup that includes red algae (Rhodophyta) and green plants/algae (Viridiplantae); chloroplasts from primary endosymbiosis with cyanobacteria.

Rhodophyta

Red algae; part of Archaeplastida; often marine; chloroplasts derived from primary endosymbiosis.

Chlorophyta

Green algae; part of Viridiplantae; among the green lineage (Chlorophytes).

Streptophytes

Group within Viridiplantae that includes land plants and some green algae; relates to the plant lineage.

Viridiplantae

Green plants and green algae; includes Chlorophyta and Streptophyta.

Chloroplast membranes in Archaeplastida

Chloroplasts have two membranes in Archaeplastida, reflecting primary endosymbiosis with cyanobacteria.

Secondary endosymbiosis

When a photosynthetic eukaryote is engulfed by another cell, leading to chloroplasts with additional membranes.