Eukaryotic Diversity

Horizontal Transfer

Associated with endosymbiosis.

Mitochondria and Chloroplasts

Key endosymbiotic features derived from bacterial lineages

8 Major Lineages & When it Diversified

Pre-Cambrian : Alveolates, Stramenopiles, Rhizarians, Excavates, Plants, Amoebozoans, Fungi, and Animals.

Choanoflagellate

The closest relative to all animals.

Alternation of Generations

Land plants alternate between sporophyte and gametophyte stages.

Alveolates

• Air sacs under the cell membranes

• Unicellular

• Mostly photosynthetic

• Dinoflagellates for organic matter in oceans

Pseudopods

Extensions of the cytoplasm with cytoskeletal elements used to move and feed

Carotenoids

Photosynthetic pigments in chloroplasts

Mycelium

The main body of the fungus, which has large surface area:volume

Synapomorphy

shared derived trait

Mitochondria Membranes

Eukaryotes with mitochondria typically have two membranes (inner and outer).

Primary Endosymbiosis & what it forms later

non-photosynthetic eukaryotic cell engulfing a cyanobacterium. this forms red algae, green algae, and land plants.

Secondary Endosymbiosis Definition

Other photosynthetic eukaryotes, including some protists, have undergone secondary endosymbiosis.

Artificial Selection Experiments

They used unicellular organisms and selected for traits that favor multicellularity.

Choanocytes Resemblance

Choanocytes, found in sponges, resemble choanoflagellates.

Dinoflagellates Abundance

Dinoflagellates are abundant and contribute to organic debris on the ocean floor.

Coral-Dinoflagellate Relation

Corals use dinoflagellates for carbohydrate production.

Stramenopiles & Examples of Uni/Multicellular

• Have two flagella with row of hairs in males, but some species have reduced or lost them

• Unicellular - Diatom

  • Deposit silica in cell walls

  • PHOTOSYNTHETIC

  • Diatomaceous earth

• Brown Algea (multicellular)

Diatoms Silica Deposition

They deposit silica within structures resembling cell walls, creating different shapes.

Diatomaceous Earth Use

Diatomaceous earth contains diatom shells with sharp, jagged edges, used to prevent pest invasions.

Brown Algae Pigments

They have carotenoids, giving them a brownish color.

Cellular Slime Molds Vegetative State

In a vegetative state, they are single-celled with a haploid nucleus, reproducing through mitosis and fission.

Opisthokonts & Common Ancestor

• If flagella are present, they are on the back (posterior) of the cell.

• Fungi

• Animals

• Choanoflagellates

• Common ancestor is the PROTIST

Limestone Production

Rizarians (specifically, Foraminifera) are responsible for much of the limestone production due to their calcium carbonate shells.

Saprobes Definition

Saprobes absorb nutrients from dead organic matter.

Hyphae Definition

Hyphae are tubular branches that extend immense distances underground.

Dry Rot Definition

Fungal infections can encroach within the xylem of plants, causing dry rot.

Waxy Cuticle Definition

Waxy cuticle to prevent water loss

Mycorrhizae Benefits

promote nutrient uptake with larger root systems

Early Plant Lineages

The earlier lineages of plants were nonvascular and needed to live close to water sources.

Gamete and Spore Production

Gametes are produced by mitosis, and spores are produced by meiosis.

Early Land Plants

Early land plants (bryophytes) had a large gametophyte body.

Sporangium Function

The tip of the sporangium ruptures, releasing haploid spores into the environment.

Sporophyte Growth

Which means what follows fertilization is a sporophyte which grows out of the gametophyte.

What are the prokaryotes and eularyotes?

bacteria are prokaryotes; everything else are eukaryotes

2 types of prokaryotes

bacteria and archaea (gave rise to & more related to eukaryotes)

5 events leading to eukaryotic evolution

1. Flexible cell membrane for more endocytosis

2. Complex cytoskeleton (forms flagellum)

3. Nuclear envelope & organelle membranes

4. Appearance of digestive vacuoles

5. Acquisition of mitochondria & chloroplasts for endosymbiosis

How many membranes start and end in primary & secondary endosymbiosis?

start with 3, end with 2

Rhizaria & Examples

• Long, thin pseudopods (arms of cytoplasm)

• Unicellular

• Large % of ocean sediments

• Foraminiferans (CaCO3 and limestone)

• Radiolarians (glassy endoskeletons)

Amoebozoans

• no distinct shape

• lobe-shaped pseudopods

• form into slug form (pseudoplasmodium) under unfavorable conditions

Fungi

• NOT PHOTOSYNTHETIC

• Digest food outside body

• Uni-celled are yeasts

• Most are multicelled

First clade to branch off after primary endosymbiosis

all aquatic, algae

challenges of land plants

desiccation/drying up, gravity, gamete dispersion

key synapomorphy of land plants

protected embryo, gametangia

land plant adaptations

• cuticle : waxy coating to slow water loss

• stomata : closeable opening to regular gas exchange & water loss

• Gametangia : organs that enclose gametes; protections

• embryos : contained within protective structures

• thick-walled spores : prevent drying

• associations with fungi

tracheids

fluid-conducting that allowed transport of water & sugars as well as provided structural support to land plants