Bio 121
Introductory Botany
Y.Ntaila
KINGDOM PROTISTA
•Has had a controversial classification.
•Need for kingdom to include non-plant nonanimal members (in evolutionary terms)
•We shall learn of protistans that resemble plants.
•In Zoology all fall under phylum Protozoa.
Plant-like Protista (algae)
Euglenophyta
Why Plant-like
Why Animal-like
Have chloroplasts with
chlorophyll (a &b)
Motility
Are photoautotrophic
heterotrophy
Unlike Moneran photoautotrophs, their chlorophyll
is membrane bound.
Habitat/distribution
Fresh water, Alimentary canals, Wet soils
EUGLENA STRUCTURE AND
FUNCTION
Plant-like Protista
(algae)Euglenophyta
• Why are they distinct from plants and
animals.
1. Their nucleus does not disappear at
mitosis as happens normally
2. Store excess food as paramylum
Plant-like Protista (algae)
Euglenophyta
• Non-chlorophyllus ones are obligate
heterotrophs
• Photoautotrophic euglenophyta are said
to be .
• facultative heterotrophs as they can
obtain food otherwise
• Read on;
• Chrysophyta (yellow-green & goldenbrown alga)
• Pyrrophyta (Dinoflagellates).
Kingdom Monera vs Protista
Kingdom Monera
Prokaryota
Kingdom Protista
(Eukaryota)
No nuclear
Membrane
Nuclear Membrane present
Organelles with no
Membrane
Membrane bound
organelles
No endoplasmic
reticulum,
Endoplasmic reticulum,
present
No mitochondria
Mitochondria present
• The changes represent advancements in
terms of evolution! Remember Monera
represent first life (3.5 Billion years ago).
• Protista evolved from Monerans about
1.7 billion years ago.
Chlamydomonas
Chlamydomonas
• is a small unicellular, mobile organism.
• It is roughly spherical in shape with two anterior
flagellae that it uses to ‘swim’ in.
• Unlike many green algae, the cell wall is not made
of cellulose (as it is in land plants) but instead of a
glycoprotein
Reproduction
• Chlamydomonas reproduces asexually
when haploid cells divide (often multiple
times) and form 2, 4, 8 or more
daughter cells, that are then released.
Sexual reproduction
• Sexual reproduction occurs when special cells
(gametes) are produced that are capable of
attaching to one another, and forming a zygote.
• This develops into a zygospore
(dormant, resistant cell) in which meiosis
occurs.
• Eventually zygospore germination occurs,
releasing hap
• Read more on Chlamydomonas