What does polyphyletic mean?
Group that is characterized by one or more homoplasies.
Are the algae a formal taxon?
NOOOOOOOO
Please explain what makes an algae…an algae.
They are eukaryotes that have chlorophyll and other pigments for carrying out oxygenic photosynthesis.
They also lack a well-organized vascular conducting system.
They have simple reproducitve structures (teehee)
What is phycology????
THE STUDY OF ALGAE!!!!
Where do MOST algae live?
- Primarily aquatic
- Planktonic
- Suspended in aqueous environment
- Phytoplankton: algae and small aquatic plants
- Zooplankton: aninmals and nonphotosynthetic protists
- Benthic
- Attached and living on the bottom of a body of water
- Neustonic
- Live at water-atmosphere interface
- Planktonic
Ok, Ok… we all know algae are water lovers. But can they survive on land??
- Some are terrestrial
- On moist surfaces
- Endosymbionts in protozoa, mollusks, worms, and corals
- Endosymbionts, ephiphytes, and parasites of plants
- Associate with fungi to form lichens
Some algae can be found in desert or on the cliffs as well.
How are the algae classified taxonomically?
Based on their cellular properties
Describe the ultrastructure of the algal cell!
- Some have extensive outer matrixes
- May have pyrenoids: molecules associated with the synthesis and storage of starch.
- They have a very very simply body plan. Extensive cytoskeleton present.
- Many algae also have extensive cell walls. Lots of chloroplasts present.
What are pyrenoids?
Molecules associated with the synthesis and storage of starch.
How do algaes obtain their food/nutrition??
They can be either autotrophic or heterotrophic (or both).
Most are photoautotrophic. Some are chemoorganoheterotrophic.
A vast majority of algae are autotrophs.
What is the thallus of algae?
It is the body of an alga. May be colonial, filamentous, uniecellular, tubular, etc.
Algae are the first organisms that can have true body plans and provide habitats for other organisms.
Describe the various mechanisms of asexual reproduction in algae.
- Fragmentation
- Thallus breaks up and each fragment forms a new thallus.
- Spores
- Zoospores - flagellated motile
- Aplanospores - nonmotile
- Binary fission
- Mitotic nuclear division followed by cytoplasmic division
Volvox is the first time we’ve seen haploid and diploid cells in the organism. Gives rise to much more elaborate organisms.
Describe the various mechanisms of sexual reproduction in algae.
- Oogonia (s., oogonium)
- Relatively unmodified vegetative cells in which eggs are formed
- Antheridia (s., antheridium)
- Specialized structures in which sperm are formed
- Zygote
- Product of fusion of sperm and egg.
Overall, how do most of the divisions of algae differ?
They tend to vary in the kind of chlorophylls (therefore giving them a different color pigment).
They can also vary in the type of carotenoids they have.
