Lecture Notes Vocabulary Flashcards: Phylogeny, Protists, and Supergroups

Vocabulary flashcards covering key terms from the lecture notes.

Hierarchical classification

Linnaeus's system for grouping species into increasingly broad categories; the basic unit at any level is a taxon.

Taxon

A taxonomic unit at any level of the hierarchy (e.g., species, genus, family).

Branch point

In a phylogenetic tree, the point where lineages diverge, representing the most recent common ancestor.

Ancestral lineage

The lineage leading back to the common ancestor prior to a branch point.

Common ancestor

The most recent ancestor shared by two or more taxa.

Polytomy

An unresolved pattern of divergence with more than two descendant lineages from a single node.

Basal taxon

A lineage that diverged early from the rest of the group; often shown at the base of a phylogeny.

Sister taxa

Two taxa that are each other’s closest relatives; they share a most recent common ancestor.

Cousin

The child of one's aunt or uncle; a relative in the same generation.

Aunt

The sister of one's parent.

Parent

One who begets or raises a child.

Grandparent

Parent of one’s parent.

Clade

A monophyletic group: an ancestral species and all its descendants.

Monophyletic

Describes a group containing a common ancestor and all its descendants.

Paraphyletic

A group that includes the common ancestor and some, but not all, descendants.

Polyphyletic

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

Protist

Informal name for mostly unicellular eukaryotes; members belong to Domain Eukarya.

Eukaryotes

Organisms with cells containing a nucleus and organelles.

Domain Eukarya

One of the three domains; includes all eukaryotic organisms.

Excavata

A major eukaryotic supergroup including diplomonads, parabasalids, and euglenozoans.

SAR clade

A major eukaryotic supergroup comprising Stramenopiles, Alveolates, and Rhizarians.

Archaeplastida

Major clade including red algae, green algae, and land plants; plastids originated via primary endosymbiosis.

Unikonta

Major eukaryotic clade including Amoebozoans and Opisthokonts.

Amoebozoans

Unikonta subgroup including many amoeboid organisms and slime molds.

Choanoflagellates

Opisthokont group closely related to animals; used to study origin of animals.

Opisthokonts

Clade including Fungi, Animals, and Choanoflagellates.

Stramenopiles

SAR subgroup with two flagella (one hairy, one smooth); includes diatoms, golden and brown algae.

Diatoms

Unicellular algae with silica cell walls; major contributors to the carbon cycle.

Golden algae

Yellow-brown carotenoid-containing algae; typically unicellular or colonial; part of Stramenopiles.

Brown algae

Largest and most complex algae; multicellular seaweeds with blade, stipe, and holdfast.

Alveolata

SAR subgroup characterized by membrane-bound alveoli under the plasma membrane.

Dinoflagellata

Alveolates with two flagella; many are photosynthetic or mixotrophic; can form red tides.

Apicomplexa

Parasites of animals; many cause diseases (e.g., malaria); contain apicoplast.

Ciliates

Alveolates with cilia; two nuclei (micronuclei and macronuclei).

Forams

Rhizarians with porous tests (shells).

Radiolarians

Rhizarians with intricate silica skeletons; marine plankton.

Kinetoplastids

Group within Euglenozoa; have kinetoplasts (mitochondrial DNA); includes Trypanosoma.

Giardia intestinalis

Diplomonadida; Giardia parasite causing giardiasis.

Trichomonas vaginalis

Parabasalida; sexually transmitted parasite; contains hydrogenosomes.

Euglenozoa

Clade including kinetoplastids and euglenids; characterized by crystalline rod in flagellum.

Kinetoplast

Structure within kinetoplastids containing multiple copies of mitochondrial DNA.

African sleeping sickness

Disease caused by Trypanosoma brucei; transmitted by tsetse fly.

Trypanosoma brucei

Species causing African sleeping sickness.

Trypanosoma cruzi

Parasite causing Chagas disease; transmitted by Reduviid bugs.

Chagas disease

Disease caused by T. cruzi; reservoirs include mice, opossums, armadillos.

Reduviid bug

Assassin bug; vector for T. cruzi.

Leishmaniasis

Diseases caused by Leishmania spp.; transmitted by sandflies.

Leishmania major

Species causing cutaneous leishmaniasis.

Leishmania donovani

Species causing visceral leishmaniasis.

Cutaneous Leishmaniasis

Skin infection caused by Leishmania spp.

Euglena

Genus of mixotrophic flagellates; often with eyespot.

Merozoite

Stage of malaria parasite that invades red blood cells after liver stage.

Sporozoites

Infective form that travels to liver; produced in mosquitoes.

Gametocytes

Haploid sexual stages that differentiate into gametes.

Oocyst

Zygote stage in mosquito gut that yields sporozoites.

Meiosis

Cell division producing haploid gametes; occurs in parasite life cycles.

Malaria

Disease caused by Plasmodium spp.; transmitted by Anopheles mosquitoes.

Anopheles

Mosquito genus that transmits malaria.

Tsetse fly

Fly (Glossina) that transmits Trypanosoma brucei.

Mitochondria

Organelles with circular DNA; evolved via endosymbiosis.

Plastids

Organelles like chloroplasts; originated via endosymbiosis.

Endosymbiotic origin

Theory that mitochondria and plastids originated as free-living bacteria inside host cells.

Phycoerythrin

Pigment in red algae giving red coloration; enables light absorption in deep water.

Red algae

Archaeplastida group; often multicellular seaweeds; contain phycoerythrin.

Green algae

Archaeplastida group; includes Chlorophytes and Charophytes.

Chlorophytes

Green algae group including Ulva; typically aquatic.

Charophytes

Green algal lineage closely related to land plants.

Land plants

Embryophytes; part of Archaeplastida within the green lineage.

Ulva

Ulva (sea lettuce); a genus of green algae (chlorophyte).

Caulerpa

Intertidal chlorophyte; example of green algae.

Amoebozoans

Unikonta group including amoebas and slime molds.

Slime molds

Amoebozoans that form sporangia; includes plasmodial slime molds.

Tubulinids

Group of Amoebozoa; lobose amoebae common in soil and freshwater.

Nucleariids

Unikonta group related to fungi; unicellular heterotrophs.

Fungi

Kingdom within Opisthokonts; absorptive heterotrophs with chitin cell walls.

Choanoflagellates

Opisthokont group closely related to animals; informs animal origins.

Endosymbiotic theory

Idea that mitochondria and plastids originated from endosymbiotic bacteria.