Evolvability and Complexity

Question 1

“Blended inheritance”

Answer 1

the phenotypes should just becoming to a common average, so a counter to evolutionary progress

Question 2

“natural inheritance” (1889)

Answer 2

the conception of a rough stone, having in consequence of its roughness, a vast number of natural facets, on any of which it may rest in “stable equilibrium”

when the stone is pushed, it will totter on an edge, but will regress to its first position when pressure is withdrawn.

However, if a very strong psuh is given the stone will be forced

Question 3

Assembly theory

Answer 3

explains and quantifies selction and evolution

uses the Molecular Assembly Index (MA)

the idea:
you have molecules, if you were assembling these molecules and disassembling them, how quick would it be ?
as the molecule gets bigger (more complex) the chance of assembly is harder and harder

if there is selection to maintaining those molecules then, a “sweet spot” forms, where very complicated mlecules better survive selection

in selection model, the intermediate molecules were not able to be maintained (so the ones before the threshold)

Question 4

evolvability

Answer 4

an organism’s capacity to generate heritable phenotypic variation

evolvability is closely tied to degrees of modularity, and complex systems emerge from this dynamic exchange

Question 5

what are the ways to increase evolvability

Answer 5

1. increased modularity
2. parcellation
   a system that looks simple can be separated into many simple ones
3. gene duplication
   like in the Cambrian explosion where increase in gene numbers may have facilitated rapid evolution of unique body plans

Question 6

complex stable stages

Answer 6

The number of possible stable stages is related to the number of genes and hormones , but not in a linear way

complex systems have emergent properties not predictable by the interaction of their parts

Question 7

how is a modular phenotype more robust than and integrated phenotype

Answer 7

A modular phenotype is fragmented, which allows for independent variation and decoupling of pleiotropic interactions.

Question 8

heterochrony

Answer 8

has the potential to expand continuous variation

changes only the timing or rate of development to produce different phenotypes.

ex:
- peramorphosis (adultation)
acceleration of developmental rate
- pedomorphosis (juvenilization)
neoteny of developmental rate

Question 9

heterotropy

Answer 9

In contrast to heterochrony

has the potential to expand discontinuous variations

changes to the positions of a developmental process to produce different phenotypes
(ex: limb development)