Diatoms Flashcards
describe diatoms as living snowflakes
- referred to this due to the intricacy of the different forms (there is high variety and diversity in this group)
what is the most highly diverse species we have talked about
diatoms
What is a frustule
diatoms have this protective glass like silicon dioxide cell wall, this takes less energy to produce than a cell wall and is an anti microbial/anti-herbivore device (even if they’re eaten they come back out intact)
What is the similarity between diatoms and chrysophytes
- they alll have chl a + c and fucoxanthin
- their photosynthate storage product is known as chrysolaminarin
Describe the morphologies of diatoms
- radial centric diatoms (look like perfect circles)
- raphid and araphid diatoms (raphid is the line dividing the center) - these are bilaterally symmetrical
- bipolar and multipolar centric diatoms
describe pennate diatoms
- they are bi laterally symmetrical
- common in freshwaters and typically attached to surfaces
describe radial centric diatoms
- they have disc shaped frustules and exhibit radial symmetry
- are common in marine environments
What does the raphe of raphe pennates of the diatoms do
it secretes mucus to move along surfaces - so these raphe pennates are called fast moving diatoms
what are the fast moving diatoms
the raphe pennates that secrete mucus
what are the two halves of the diatoms called
upper = epitheca/epivalve
lower = hypotheca/hypovalve
- the epitheca is the slightly larger half
do diatoms have pores
yes they have a lot of pores
what does the raphe do
divides the frustules of diatoms into symmetric halves and secretes mucus
difference between striae and costae
striae is the little dots on diatoms while costae is more like continuous bands (ribcage look)
which ones are older/more recent in the diatoms: radial or pennate
radial = older
pennate = more recent
describe the gamete life history of centric diatoms and pennate diatoms
- centric diatoms produce haploid gametes and these look similar to chrysophytes - these gametes are motile
- pennate diatoms also go into a haploid state but these gametes are not flagelllated