The Protists

1
The Protists

• Eukaryotes.
• Most unicellular.
• Most aerobic.
• Moist environments
• Can be photoheterotrophs, photoautotrophs,
  chemoheterotrophs or mixotrophs.
• Flagella or cilia.
• All protists can reproduce asexually, some
  sexually

2
Endosymbiosis

• Eukaryotic cells evolved from symbiotic
  combinations of prokaryotic cells.
• Mitochondria ? aerobic heterotrophic prokaryotic
  cells
• Chloroplasts ? photosynthetic prokaryotes

3
Evidence for Endosymbiosis

• Similarities between modern bacteria and the
  chloroplasts/mitochondria of eukaryotes
• size
• enzymes
• circular DNA molecules
• process of division
• ribosomes similar

4
The Candidate Kingdoms

• Archaezoa
• Euglenozoa
• Alveolata
• Stramenopila
• Rhodophyta
• Green Algae

5
Candidate Kingdom Archaezoa

• Giardia
• have two nuclei, flagella, and no mitochondria
  (parasites)

6
Candidate Kingdom Euglenozoa

• Autotrophic and/or heterotrophic flagellates
• Euglena
• 1 or 2 flagella
• Kinetoplasts
• parasitic, e.g. African Sleeping Sickness (bite
  of tsetse fly)

Trypanosoma
7
Candidate Kingdom Alveolata

• Dinoflagellates, phytoplankton, cause red tides,
  color from xanthophyll.
• Apicomplexans, plasmodium, causes malaria.
• Ciliates, paramecium

Next Group
8
Dinoflagellates
http//www.microscopy-uk.org.uk/mag/artsep01/dinof
.html http//www.microscopy-uk.org.uk/mag/indexmag
.html
9
Apicomplexans
Leishmania
Parasite infected erythrocyte
10
Life history of Plasmodium
11
Ciliates
Stentor
Paramecium
Vorticella
12
Pseudopod ProtistsTaxonomic lineage unclear,
so no clear kingdom found i.e. misfits

• Rhizopods, amoebas
• Actinopods, radiolarians and heliozoans (delicate
  silica shells).
• Foraminiferans, marine with porous calcium
  shells. Used as index fossils.
• Slime Molds, cytoplasmic streaming

13
Rhizopod

• Amoeba

14
Actinopods
Radiolarians
15
Foraminiferans
16
Slime Molds

• Plasmodial Slime Mold Myxomycota.
• Heterotrophic,brightly colored, multinucleated
  ameboid mass.

17
Candidate Kingdom Stramenopila

• Diatoms (bacillariophyta) unicellular plankton
  with box-like silica walls. Diatomaceous earth.
• Golden Algae (chrysophyta) yellow and brown
  carotene and xanthophyll pigments
• Brown Algae (phaeophyta)- largests and most
  complex. Seaweeds and kelps, may be as long as
  60m.
• Water Molds (oomycota) white rusts and downy
  mildews

Next Group
18
Diatoms
19
Golden Algae - Chrysophyta
20
Brown Algae - Phaeophyta
Kelp Harvesting
21
Kelp Structures

• Analogous plant-like structures
• Body thallus
• Root-like structure holdfast
• Stem-like structure stipe
• Leaf-like structure - blades

22
Water molds, white rusts and downy mildews
Water mold
White rust on spinach
23
Candidate Kingdom Rhodophyta

• Red color from pigment
• Marine
• Multicellular
• Carrageenan thickener

24
Candidate Kingdom Green Algae
Many scientists advocate inclusion of green
algae into the plant kingdom. More than 7000
species, mostly freshwater.
Unicellular Chlamydomonas Colonial
Volvox Multicellular Ulva
Ulva
25
Green Algae - Chlorophyta
Volvox
Chlamydomonas
Spirogyra
26
Chlamydomonas Life Cycle
27
Ulva Life Cycle