Eukaryotes

What are some shared derived characteristics of eukaryotes?

• nucleus

• endomembrane system (organelles)

• cytoskeleton

• mitochondria

cytoskeleton

network of fibers;

functions as support and shape change

serial endosymbiosis

one cell engulfs another and both benefit

primary endosymbiosis

a prokaryote was engulfed by another cell

proteobacteria →

mitochondria

cyanobacteria →

plastids (chloroplasts)

secondary endosymbiosis

a eukaryote was engulfed by another cell

draw primary endosymbiosis

draw secondary endosymbiosis

All eukaryotes are protists except…

land plants, fungi, and animals

5 supergroups

1. archaeplastida

2. SAR

3. amoebozoa

4. opisthokonta

5. discoba

Most protists are multicellular or unicellular?

unicellular

protists

first eukaryotic cells

What are three possible nutritional strategies of eukaryotes?

1. photoautotrophs

2. heterotrophs

3. mixotrophs

Photoautotrophs get energy using…

chloroplasts

Heterotrophs get energy using…

organic molecules

Mixotrophs get energy using…

photosynthesis & heterotrophic

archaeplastida branches

• red algae

• chlorophytes

• charophytes

• land plants

archaeplastida shared derived character

chloroplast from primary endosymbiosis of a cyanobacterium

Is all of archaeplastida photosynthetic?

yes

red algae

• phycoerythrin

• multicellular and highly branched

• warm tropical oceans

phycoerythrin

red photosynthetic pigment that absorbs blue & green light (deep into water) → deep habitats

green algae

chlorophytes & charophytes;

• chloroplasts very similar to land plants

What is most closely related to land plants?

charophytes

SAR branches

• rhizaria

• alveolates

• stramenopiles

SAR shared derived character

secondary plastid from red algae

stramenopiles shared derived character

2 paired flagella: long hairy + short smooth

3 main groups of stramenopiles

1. diatoms

2. golden algae

3. brown algae

wall of diatom

• silicon dioxide → glass-like

• 2 overlapping parts

• protection

diatomaceous earth

filters, absorbs, medicinal

features of golden algae

• yellow & brown carotenoids

• most are unicellular

• tiny scales of silica or CaCO₃

Where is golden algae found?

freshwater & marine biomes

Golden algae are nanoplankton, meaning that they are…

• 2 - 10 um

• diverse group

• cannot swim against the current

features of brown algae

• most complex protists

• multicellular

• large (few cm to 75 m)

• seaweed

Where is brown algae found?

cold marine waters;

form kelp forests, which inhabit a variety of other organisms

What is the commercial importance of brown algae?

• some edible

• algin

algin

polysaccharide in cell walls of brown algae;

thickener

alveolates shared derived character

alveoli (sacs under PM)

3 groups of alveolates

1. ciliates

2. dinoflagellates

3. apicomplexans

ciliates

cilia; move & feed

features of dinoflagellates

• 2 flagella; spin

• plankton

dinoflagellates bloom

population explosion;

carotenoids;

ex: red tide

apicomplexans

apical complex that penetrates host cells

ex: plasmodium → malaria

rhizaria shared derived character

genetic similarities & shells

2 groups of rhizaria

1. radiolarians

2. foraminiferans (forams)

radiolarians

internal skeleton of silica

foraminiferans (forams)

tests: porous shells of CaCO₃;

thick marine sediment : billions of shells

amobozoa branches

• slime molds

• entamoebas

amobozoa shared derived character

• genetic similarities

• blob shape

• pseudopodia

entamoeba histalytica

amoebic dysentery

opisthokonta branches

• nucleariids

• fungi

• choanoflagellates

• animals

opisthokonta shared derived character

• genetic similarities

• single, posterior flagellum

nucleariids

• protists

• sister taxon of fungi

choanoflagellates

• protists

• sister taxon of animals

discoba branches

• trypanosome

• euglenids

discoba shared derived character

crystalline rod in flagellum

trypanosome

African sleeping sickness

euglenids shared derived character

secondary plastids from green algae

draw the tree of eukarya with the 5 supergroups