[UNIT 1] Eukaryotic Diversity Concepts Quizlet (Kraft, FSU, Fall 2026)

Aristotle

Came up with the 'scala naturae', an outdated, human-centric hierarchical ranking of life diversity from simple organisms at the bottom to complex, human-like organisms at the top.

Existing variation

Selection can only act upon...

Charles Darwin (+ Alfred Wallace)

Studied Galapagos finches; came to the conclusion that speciation occurs due to selection (survival of the fittest) and that this process results in a branching tree of different species (descent with modification)

Carl Woese

Proposed a three (3) domain system - Bacteria, Eukarya, Archea (Modern framework for classification)

Robert Whittaker

Proposed a 5 kingdom system (Animalia, Plantae, Fungi, Protista, Monera) - outdated

Carl Linnaeus

The father of taxonomy; popularized the use of 'binomial nomenclature' (e.g. Homo sapiens) to describe and classify life

Primary endosymbiosis

Host cell (protoeukaryote) engulfing PROKARYOTE (led to development of simple membrane-bound organelles and the formation of an ancestral eukaryote) - also happened TWICE

Secondary endosymbiosis

Ancestral eukaryote engulfing another ancestral EUKARYOTE (led to development of complex plastid organelles with multiple membranes)

FIRST (1) primary endosymbiosis

Engulfing of a bacteria by a protoeukaryote; established a mutualistic relationship where the bacteria provided ATP in exchange for food from the host cell. (created HETEROTROPHIC eukaryote)

SECOND (2) primary endosymbiosis

Engulfing of a cyanobacteria by a heterotrophic eukaryote (created AUTOTROPHIC eukaryote)

Archaeplastida

Second (2) primary endosymbiosis gave rise to this lineage of photosynthetic organisms?

Protists

Lineage of eukaryotes that DID NOT go through 2nd primary endosymbiosis but can still photosynthesize because of indirect acquisition of chloroplasts through SECONDARY endosymbiosis?

Primary = acquiring an ability DIRECTLY from a smaller cell (e.g. photosynthesis)

Secondary = INDIRECTLY acquiring an ability by engulfing a cell that has already obtained that ability

1st primary endosymbiosis: gave rise to HETEROTROPHIC eukaryote (obtained mitochondria)

2nd primary endosymbiosis: created AUTOTROPHIC eukaryote (obtained chloroplast)

Differentiate secondary and primary endosymbiosis, and explain the difference between 1st and 2nd primary endosymbiosis

Red and green algae, all land plants

What organisms does supergroup Archaeplastida contain?

Cultural services

This ecosystem service provides the benefits of recreation, spiritual/ religious enrichment, cultural heritage:

Regulating services

This ecosystem service provides the benefits of pest regulation, waste decomposition:

Supporting services

This ecosystem service provides the benefits of nutrient cycling, primary production, pollination:

Provisioning services

This ecosystem service provides the benefits of food, drinking water, wood, natural gas, materials for clothes, medicinal benefits

Overharvesting, exploitation of resources

What are some potential issues with bio-prospecting?

1. Habitat loss

2. Overharvesting

What are the two biggest threats to biodiversity?

Museums, citizen science projects, herbariums

What are some examples of repositories (stores of information) of biodiversity?

Anton van Leeuwenhoek

"Father of microbiology", invented the first compound microscope to view single-celled organisms

Ernst Haeckel

"Father of ecology", came up with terminology we still use in the modern day such as 'phylum', 'protista', 'ecology'. Came up with the first phylogenetic cateogrization of life (Plantae, Animalia, Protista) - outdated

Monophyletic

A taxon that contains a group of organisms and the common ancestor of all in that group

Paraphyletic

A taxon that only includes some but not all of the descendants of a common ancestor

Polyphyletic

A taxon that does NOT include the most recent common ancestor of all descendants in the group

Homology

A similarity between two organisms because of shared common ancestry

Analogy

A similarity between two organisms that are NOT related, likely due to similar selective pressure on both

Phylogeny

A depiction of the possible evolutionary history of a group of related species

Mass extinction event

What is is called when more than half the species present on earth go extinct in a short period of time, rapidly enough that they cannot recover?

Archean, Proterozoic, Phanerozoic.

We are currently in the Phanerozoic eon.

Name the three eons? Which are we in currently?

Permian extinction

Which extinction event was marked by a big shift in carbon cycling and was known as "the great dying"? ~252 MYA

Cretaceous-Paleogene extinction (5th mass extinction)

Which extinction event was caused by an asteroid striking the Yucatán peninsula, wiped out the non-avian dinosaurs, and led to a major shift in dominant life forms (allowing flowering plants to thrive)? ~65 MYA

Morphological data

Type of observational data that provides us with some idea of the visual similarities between different organisms, but is not the most helpful when constructing a phylogeny (as it does not account for convergence vs homology)

Molecular data

Type of data that provides us with a better idea of the relationships between organisms because of differences and similarities in genetic code, hinting to possible divergence patterns

Node

A point on a phylogenetic tree where two (or occasionally more) branches diverge from one ancestor

Clade

On a phylogenetic tree, a group of species and its single common ancestor

Taxon

Any group of organisms in a unit within a phylogenetic tree

Sister taxa

Two groups that diverged from the same most recent ancestor

Ediacaran fauna

Earliest known animals, extremely strange, plant-like morphology; fossils from ~600 MYA

Cambrian explosion

Period of history when, due to increased oxygen in the atmosphere, organisms began to rapidly evolve and diversify. ~99% of phyla that evolved during this period are extinct. Bizarre fossil forms show evolution of bigger, more active animal species.

Hallucigenia

Strange eukaryotic fossil from the cambrian explosion that is poorly understood.

1. It was a period in time where evolution was free to experiment

2. Our fossil record is still very poor

Potential reasons why organisms from the cambrian explosion seem to be so weird?

Seedless vascular plants (ferns, horsetails)

Type of plant that dominated the landscape during the carboniferous era? (The time of early tetrapods like amphibians & early reptiles)

Bryophytes (mosses)

Dominant land vegetation for the first 100 million years of plant evolution?

1. Land plants form the base of the terrestrial animal food chain

2. They provide lots of oxygen

Why is land vegetation so significant to evolutionary history?

Supergroup Excavata

Unicellular protists that share morphology (excavated groove), but are likely paraphyletic. Some are photosynthetic (Euglena); Some are endoparasitic and lack mitochondria (Diplomonads, Parabasalids)

Supergroup Chromalveolata

2 Subgroups = Alveolates (diverse unicellular organisms) and Stramenopiles (mostly photosynthetic algae)

United because of similarities in morphological data

Alveolates

Subgroup of Chromalveolata that includes:

Dinoflagellates - photosynthetic unicellular marine plankton

Apicomplexans - parasites that include plasmodium (malaria) and toxoplasma gondii (toxoplasmosis)

Ciliates - paramecium (heterotrophic, reproduce by conjugation)

Stramenopiles

Subgroup of Chromalveolata that includes:

Diatoms - unicellular photosynthetic marine plankton with silica wall that fossilize incredibly well

Brown algae - multicellular photosynthetic 'seaweeds'

Oomycetes - decomposers or parasites (NOT fungi despite the name)

Supergroup Rhizaria

Amoeba-like marine or freshwater plankton with threadlike pseudopodia used to move and capture prey. (Forams/ foraminiferans have a porous CaCO3 shell, Radiolarians have threads extending from a hard silica shell)

Supergroup Archaeplastida

First organisms to evolve chloroplasts (through primary endosymbiosis)! All in this group are photosynthetic. Contains green algae, red algae, and land plants.

Charophytes

The sister taxon to land plants, supported by molecular and morphological data. Land plants share unique traits with this group.

1. A unique way of synthesizing cellulose within the cell walls

2. A phragmoplast forms during cell division

What are some unique traits that land plants ONLY share with Charophytes?

Phragmoplast

A group of aligned cytoskeletal microtubules & golgi-derived vesicles forming between daughter

nuclei of a dividing plant cell, serves as a scaffold for the cell plate (where the cell wall will eventually develop). These only form during cell division in land plants and charophytes.

Land plants (Embryophytes)

Member of supergroup Archaeplastida. Moved to land ~475 MYA and have unique adaptations for terrestrial life that charophyte algae lack.

Algae --> 1st nonvascular land plants (Bryophytes/ mosses) --> Seedless vascular plants (Pterophytes and Lycophytes: ferns, horsetails) --> Seeded vascular plants (Spermatophytes: cycads, conifers, flowering plants)

Name the events in the phylogeny of the diversification of land plants?

Xylem

Vascular tissue that carries WATER throughout a plant

Phloem

Vascular tissue that carries NUTRIENTS throughout a plant (think: Phloem = food)

Bryophytes

Seedless nonvascular plants, including mosses, hornworts, liverworts. Small, herbaceous, non-woody. Need access to water for reproduction (via spores).

Lycophytes and Pterophytes

Seedless VASCULAR land plants, including ferns. Larger, herbaceous, and non-woody. Require water for reproduction (via spores). Cell walls strengthened with lignin to stay upright and transport water/nutrients. Have true leaves.