Micro-invertebrates Flashcards
Which organism crash-landed on the moon a few years ago?
Tardigrades
What are the two classes focused on in this lecture under the phyla rotifera?
Monogononta and Bdelloidea
Give a little info on each of these in the phyla rotifera;
Seisonidea
Monogononta
Bdelloidea
Acanthocephala
Seisonidea: amphimictic, ~2 species
Monogononta: cyclical parthenogens: apo/amphimictic, ~1000 species
Bdelloidea: apomictic, ~380 species
Acanthocephala: amphimictic, parasites
What is Asexual reproduction also known as?
(parthenogenesis = virgin birth)
How do Bdelloidea reproduce?
Only asexually
These caused an evolutionary scandal because no organism has ever survived that long (80 million years) with only asexual reproduction
How do Bdelloidea survive environmental stresses?
They survive desiccation by entering cryptobiosis and when water is returned they have not aged.
What are the two types of dormancy
Diapause (resting egg) and Quiescence (Cryptobiosis)
What types of Cryptobiosis are there?
- anhydrobiosis
- cryobiosis
- anoxybiosis
- osmobiosis
What is (vertical gene transfer) and HGT (Horizontal gene transfer)
*Vertical Gene Transfer: the transfer of a gene from an organism to another which is a direct descendant.
*Horizontal Gene Transfer: the transfer of a gene from an organism to another which is NOT a direct descendant
Tagrada
These are also very resistant and can go into cryptobiosis
Which Rotifer enters a state of dormancy known as Quiescence “hidden life” under unfavourable conditions?
Bdelloidea
Which Rotifer Class exhibits HGT?
Bdelloidea
What is male/female reproduction called?
Amphimictic
Why are Seisonidea rare amongst rotifers?
They are Amphimictic (male/female breeding) which is rare in rotifers. They also live in gills. 2 species
Why are Monogononta unique amongst rotifers?
They are cyclical parthenogens. They can turn to apomictic reproduction when conditions are harsh.
