Lecture 2 Flashcards
Origin of life and diversification
1
Q
Terrestrial
A
- Expensive movement
- Water limited
- Eliminating wastes hard
- Oxygen abundant
- Variable conditions
2
Q
“Simple” animals
A
- Organs like gills, kidneys, guts and circulatory systems did not exist
- Ciliary/flagellar locomotion
3
Q
Marine
A
- Salty (high density)
- Water ‘unlimited’
- Easy to excrete waste
- Oxygen can be challenging
- Stable
4
Q
Estuaries
A
- Intermediate to marine/freshwater
- Usually more nutrients
- Highly variable conditions
5
Q
Freshwater
A
- Very low salt (less dense)
- Water ‘unlimited’
- Easy to excrete wastes
- Spatiotemporally variable
6
Q
Choanoflagellates
A
- Likely our closest unicellular relatives
- Henry James-Clark (1867) morphologically resembles the choanocytes of Porifera
- May be particularly relevant to animal life
7
Q
Brunet et al.
A
(2019)
- Discovered choanoeca flexa
- Photosensitive inversion
- Apical actomyosin conserved across animals
8
Q
Apical actomyosin
A
The generalized structural body plan that characterises a group of organisms and especially a major taxon
9
Q
What likely spurred the Cambrian radiation?
A
1.) Arms race of body plans
2.) Agronomic revolution and geological change
10
Q
Homeostasis
A
The maintenance of relatively stable conditions that support living systems
11
Q
Bauplan approach
A
- Structural design for functional work
- All processes and systems within an organism must work collaboratively
