Developmental Plasticity and Symbiosis

• Environment is not as bad as we thought• Reaction Norm vs. Polyphenism• Environmental regulation of phenotypes• Learning

Nature vs Nurture?

Plasticity• Phenotypic • Developmental

Reaction Norm

Polyphenism

Dung Beetles and Ants: Diet-induced polyphenisms

• Queen Ant vs Worker Ant• Horned male Dung Beetles:

Protector of the Female.

Diet and Gene regulation• DNA methylation• viable-yellow of Agouti-

transposon in cis-regulatory element.

Predator-induced Polyphenisms• Kairomones

Predator-induced Polyphenisms: Amphibians• More muscle mass in tail.• Kairomones can make the

tadpole more sensitive to environmental insults: fertilizers et al.

Figure 17.6

Good Vibrations

Fig. 17.7

Geronimo

Temperature and Sex

Temperature and Butterfly wings

Environment, Anxiety, and DNA methylation

Learning

• No division• New Neurons• Changing connections

Nervous system: Plasticity and Learning

Experience and vision

• Hubel and Wiesel (1960s)• Right eye occluded for 3

months• Occurs within 4 to 6 weeks

of birth

Life cycle and Polyphenisms

• Diapause• Larval Settlement

Spadefoot Toad

Symbiosis• Parasitism• Mutualism• Commensalism

Developmental Symbiosis: passing on the help

• Vertical transmission• Horizontal transmission• Wolbachia infection

Shedding light on symbiosis• Euprymna-Vibrio• Light organ development and luminescence

Obligate mutualism

Spotted Salamander and Oophilia amblystomatis

Filariasis worm and Wolbachia

Symbiosis in mammalian intestine