9:04
Published December 21, 2016

What Caused Life's Major Evolutionary Transitions

Description

Explore the fascinating transition from early cells to multi-celled animals. This transition, as well as several other major evolutionary transitions, dramatically increased the complexity of lifeforms on our planet. 

Sources

OVERVIEW OF MAJOR TRANSITIONS

This animation was based on a paper by Stuart West et al called Major Evolutionary Transitions in Individuality 

Dr West's paper defines major transitions in a slightly narrower way than earlier workers on the subject. For a broader definition see the book by John Maynard Smith and Eörs Szathmáry on the topic called The Major Evolutionary Transitions in Evolution

MITOCHONDRIA 

The paper by Dr Margulis (Sagan) on the origin of mitochondria is called On the Origin of Mitosing Cells.

Note that in it she presents several ideas cautiously as hypothesis. While some aspects of the paper are now known to be incorrect, she was spot on about the origin of mitochondria.

VIROIDS 

The free living genes discovered by Dr Diener were made of RNA. Read about them in his paper called Potato spindle tuber “virus”: IV. A replicating, low molecular weight RNA

Here is an excellent Wikipedia article on them I suggest looking over first. It includes a schematic of the species Diener found: https://en.wikipedia.org/wiki/Viroid 

EXPERIMENTS SHOWN IN THIS ANIMATION 

Phagotrophy by a flagellate selects for colonial prey: A possible origin of multicellularity

Experimental evolution of multicellularity

Auto-/heterotrophic endosymbiosis evolves in a mature stage of ecosystem development in a microcosm composed of an alga, a bacterium and a ciliate