Biology 4

Name all supergroups of Eukarya

1. Excavata

2. SAR (stramenopila, aveolata, rhizaria)

3. Amorphea (fungi, animals, amoebozoa)

4. Archaeplastida (green algae, red algae, land plants)

Excavata

ventral feeding groove supported by microtubules

Parabasalia

parasitic and mutualistic
- lost mitochondria

Euglenozoa (2 phyla)

Kinetoplastida and Euglenids

Kinetoplastida

singular large mitochondria called kinetoplast

Euglenids

• secondary endosymbiosis of chloroplasts from green algae—> green because of Chlorophyll A and B

• no cell wall but flexible & rigid pellicle in plasma membrane

SAR (synapomorphies and clades)

synapomorphies are based on DNA changes

Chromalveolata and Rhizaria

Chromalveolata

• synapomorphy: secondary endosymbiotic origin of chloroplasts (red algae/lineage)

• many lack chloroplast— now heterotrophic

  • We know they had chloroplasts because they have genes coding for them

  • Many of those genes moved to nucleus

  • Have plastids/plastid-like organelles that are derived from chloroplasts

Chromalveolata (clades)

Stramenopila (Chromista)

Alveolata

Stramenopila

• synapomorphy: 2 unequal flagella and the longer one is tinseled

• Contains fucoxanthin pigment as well as Chlorophyll A and C

  • photoautotrophs

  • SAR synapomorphy: chloroplasts by secondary endosymbiosis

What are the major subgroups of stramenopila?

Bacillariophyta (diatoms)

Phaeophyta (brown algae)

Oomycota (water molds)

Bacillariophyta

diatoms

• unicellular

• synapomorphy: cell walls of hydrated silica (glass like material) in organic matrix

• synapomorphy: box and lid cell wall—two halves

• fresh water + marine habitats

• photosynthetic

• diatomaceous earth: dead diatoms shells sunk and turned into sediment with glassy material in it

• diploid life cycles; gametes = haploid

Phaeophyta

Brown algae

• synapomorphy: cell walls contain algin (polysaccharide)

• multicellular seaweed

  • multicellular body = thallus

  • holdfast (anchor not like absorbent roots), stipe (stem), gas bladders (to suspend blades), and blades (flat leaf like but NOT leaves)

• stores food as laminarin (a type of starch different from plants)

  • beta glucose - 1,3 & 1,6 glycosidic linkages

  • 30-50 glucose residues (instead of thousands like in alpha glucose)

What is algin used as?

electrophoretic gels, agar, food thickeners

Oomycota

• water molds (not true molds/fungus)

• filamentous bodies (similar to fungi)

• Saprotroph = live on decaying organic matter

• Some heterotrophic - some are parasites

• Synapomorphy: lost chloroplasts (no plastids present)

  • Proof they HAD chloroplasts: they have 855 genes of chloroplast origin

• reproductive structures - zoospores have two flagella

Potato Blight

Caused by oomycota

mid 1800s Ireland

most people lived on potatoes

Phytophthora infestans

wiped out potatos/crops —> famine

Sudden Oak Death

California

Phytophthora spp.

several species of oak trees are dying due to infestans

Aveolata

• synapomorphy: flattened bags - membrane bound sacs under plasma membrane called alveoli

  • unknown function for some; little idea for others

Name three clades of alveolata

Dinoflagellates

Apicomplexa

Ciliophora

Dinoflagellates

• mostly marine

• synapomorphy: 2 flagella located in grooves on cell surface

• synapomorphy: under plasma membrane under alveoli they have plates of cellulose-like material

• no cell wall (though plasma membrane is like a cell wall)

• tumble like motion

• bioluminescent

• Chlorophyll A & C, xanthopylls

• food stored as starch

• some spp. symbiotic with corals (endosymbionts)

• cause red tides — due to toxin they produce eaten by shellfish —> eaten by larger animals

  • depending on amount —> may cause red tides

Apicomplexa

• ALL parasites - associated with animals

• synapomorphy: apical structure called apicoplasts used for penetrating host cells they live in

• Apicoplasts derived from plastids — have chloroplast genes and strucutre

• have non-photosynthetic plastids derived from chloroplasts — function fatty acid metabolism

• have complex life cycles

• infectious stage in life cycle called sporozoites

Malaria

apicomplexa in plasmodium spread by anopheles—which is one genus—mosquitoes (vectors) which are females only

most severe case caused by plasmodium falciperum

Malaria life cycle

1. Mosquito has to ingest haploid gametocytes when drinking blood

2. After feeding, inside the mosquito’s gut, fertilization occurs between two gametocytes forming a diploid zygote

3. Zygote undergoes meiosis, producing haploid cells (sporozoites — infectious stage) that swim all over the body

   1. some will end up in salivary gland

4. Takes a week for mosquito to become infective due to time taken for meiosis and mitosis to occur, accumulating sporozoites, and then spreading to different parts of the body

5. Mosquito bites human —> inserts saliva into humans transferring sporozoites

6. In the humans, sporozoites will swim through the blood and eventually reach the liver, where they will differentiate into a new form called merozoites

7. Merozoites asexually accumulate before leaving

   1. despites mitotically dividing, merozoite cells will look different from one another because of gene expression

8. Merozoites invade red blood cell and continue to reproduce asexually

   1. continuous infecting and lysing (destroying) RBC (its a cycle)

   2. lysing occurs at the same time (~24-48 hours)

9. some become gametocytes (haploid)

10. If mosquito bites an infected person and ingests gametocytes, cycle starts again.