Chapter 13 : Evolution And Development

Question 1

Colinearity

Question 2

Enhancers

Question 3

Evo-devo (evolutionary developmental biology)

Question 4

Gene Family

Question 5

Heterochrony

Answer 5

Focuses on the time in the developmental process at which a developmental trait is first expressed in a species, relative to when that same developmental trait is first expressed in the ancestor to the species being studied.

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Question 6

Homeobox

Question 7

Homeotic Genes

Answer 7

Genes that determine the identity and positioning of anatomical structures during development.

Ex. In fruit flies, a mutation of a particular homeotic gene results in altered transcription, leading to the growth of legs on the head instead of antenna.

Question 8

Hox Genes

Question 9

Neofunctionalization

Question 10

Neural Crest Cells

Question 11

Ontogeny

Answer 11

This is the process of individual development from a single cell, an egg cell or a zygote, to an adult organism.

Question 12

Paedomorphosis

Answer 12

(Related to heterochrony)

A trait that was formerly seen early in development in an ancestral species appears later in development in a descendant species.

Can occur in two ways:
1) reproductive traits appear earlier — progenesis
2) the onset of somatic traits is retarded — neoteny

Question 13

Paralogs

Question 14

Recapitulation

Answer 14

(Related to heterochrony)

A trait that is seen late in development in an ancestral species, but appears earlier in development in a descendant species.

Can occur in two ways:
1) genetic change that leads to a somatic trait appearing earlier in development — acceleration
2) genetic change that leads to a reproductive trait appearing later in development — hypermorphosis

Question 15

Segmentation Genes

Answer 15

Genes that are associated with patterning of the body segments during development

Question 16

Silencers

Question 17

Subfunctionalization

Question 18

What is the scala naturae?

Answer 18

It is also known as the “great chain of being”.
Where species are classified from “lowest” to “highest”.

Question 19

What is a parallelism?

Answer 19

It refers to the idea that developmental stages mirror the scale naturae — moves from simple to complex.

Question 20

What does von Baer’s law suggest about the evolution of novel traits?

Answer 20

von Baer’s law states that when comparing developmental stages of closely related species, general traits develop before the specialized traits that allow us to distinguish different species from on another.

So, embryos in closely related species resemble each other.

Question 21

What is the study of heterochrony?

Answer 21

(Look at definition)

The four types of heterochrony are: acceleration, progenesis, neoteny, and hypermorphosis.

The developmental changes can be separated into two categories:
1) changes that affect the timing of the onset of reproductive traits
2) changes that affect the timing of the appearance of non reproductive traits — somatic.

Question 22

Name two sets of homeotic genes and what they do.

Question 23

What do studies that successfully transplant Hox genes across phylogenetically distant species tell us?

Question 24

What are regulatory enhancers, and why are they important from an evolutionary perspective?

Question 25

With respect to gene duplication, what is neofunctionalization?