Incoming links: Eukaryote
This group is a mess.
But one thing you should really know, as often mentioned in Power, Sex, Suicide by Nick Lane (2006): they are all eukaryotes.
Because prokaryotes are fundamentally unable to do phagocytosis, because they have a rigid cell wall. Changing cell shape at will requires a cytoskeleton.
Archaea are more cosely related to the eukaryotes than bacteria Updated 2024-12-15 +Created 1970-01-01
The key metabolic pathway of cellular respiration.
Happens in the matrix of the mitochondrion in eukaryotes.
Eukaryotes can do phatocytosis due to their cytoskeleton Updated 2024-12-15 +Created 1970-01-01
Power, Sex, Suicide by Nick Lane (2006) page 53 suggests that one tremendous advantage of eukaryotes over bacteria is their ability to change shape due to the presence of the cytoskeleton, and the lack of a rigid bacterial cell wall.
Imagine in a world where there are only bacteria, and you can eat entire bacteria in one go, what a huge advantage that is!
- prokaryote models:
- E. Coli: the most well studied
- mycoplasma: a very minimal genus, notable species: Mycoplasma genitalium
- eukaryote
- S. cerevisiae: simplest eukaryote model. Unicellular.
- C. elegans: simplest multicellular organism model
- vertebrate:
- Zebrafish: simplest vertebrate model
- mammal:
- Mus musculus: simplest mammal model
All pages below are from the second edition from 2018. It seems that there weren't any changes in the text, the updated preface mentions
As it happens, nearly 15 years have passed since the 1st edition of Power, Sex, Suicide was published, and I am resisting the temptation to make any lame revisions. Some say that even Darwin lessened the power of his arguments in the Origin of Species through his multiple revisions, in which he dealt with criticisms and sometimes shifted his views in the wrong direction. I prefer my original to speak for itself, even if it turns out to be wrong.
This is partly addressed in the preface of the second edition from 2018.
Central thesis:
- there are two sexes because of mitochondria
- the acquisition of mitochondria was one of the most important steps in the evolution of eukaryotes.There are no known eukaryotes which never had mitochondria. Having mitochondria appears to be a requisite for being an eukaryote.Contrast this for example with multicellularity, which is highly polyphyletic.
- Apoptosis is largely regulated by mitochondria
- there are two main theories for how the mitochondria endosymbiosis started:
- parsitic hypothesis of mitochondrial endosymbiosis: a parasitic option rather than cooperative
- hydrogen hypothesis: a cooperative option rather than parasitic
Smaller points:
- 10% of our body weight (dry presumably?) is mitochondria. Also quoted at: www.nature.com/scitable/blog/student-voices/mighty_mitochondria. TODO confirm.
- eukaryotes can do phatocytosis due to their cytoskeleton
- paints a colorful picture of Peter Mitchell. Some Wikipedia edits are warranted!
- it is hard for complex organisms to evolve because longer DNA means longer replication time
- cancer is natural selection gone wrong
- multicellular organisms are not utopias where every cell lives happily. Rather, they are dictatorships, where any dissident is forced to commit seppuku. Lu Xun's petition quote comes to mind.
Nitpicks:
- the book calls ATP synthase "ATPase" in several points, which is confusing because -ase means "something that breaks", and in 2020 parlance, there are ATPases which actually break ATP: en.wikipedia.org/wiki/ATPase. The book itself acknowledges that on page 135:
The ATPase is freely reversible. Under some circumstances it can go into reverse, whereupon it splits ATP, and uses the energy released to pump protons up the drive shaft, back across the membrane against the pressure of the reservoir. In fact the very name ATPase (rather than ATP synthase) signifies this action, which was discovered first. This bizarre trait hides a deep secret of life, and we’ll return to it in a moment.
Some criticisms:
- some of the later chapters are a bit more boring, like the stuff about warm-blooded animals. Perhaps is it that Ciro Santilli is more interested in the molecular aspects than macro
- the author talks about some very recent research at the time. While this does highlight his expertise, some of the points mentioned might still be in a state of flow. This is acknowledged by the author himself on the 2018 updated preface however.
Anything that is not eukaryote, i.e. archaea and bacteria, see e.g.: Figure "Coral of life by János Podani (2019)".
Not a clade, and therefore a term better forgotten!
Does not appear to refer to any one specific phylogenetic level, it usually refers to either:
- Saccharomyces cerevisiae, the model eukaryote unicellular organism
- two phila of the fungus kingdom