Extra Reading Flashcards
What is sperm chemotaxis a form of?
Gamete signalling
What level do chemical cues released by eggs act at?
Interspecific but recent studies suggest intraspecific level by moderating sperm competition
What is sperm chemotaxis?
The attraction of sperm towards an egg using egg-derived chemicals
What was the hypothesis proposed for sperm chemotaxis?
Egg chemoattractants should attract the sperm of genetically compatible rather than non-compatible males when two males are competing for fertilisation of an egg
What were the findings for the sperm chemoattractant experiment?
Variation among males in the success of fertilising an egg
Success of a male depends on the identity of the female
Fertilisation success was high when male and female nuclear genotypes were dissimilar
In broadcast spawners, post-ejaculation female choice is likely to be more important than the choice of a mating partner
What happens if you change temperature exposure for the larvae of the arctic midge?
High or low exposure does not further up-regulate the genes or further enhance thermotolerance
What happened to the larvae of the arctic midge as experimentally temperatures were increased?
Mortality increased as temperatures increased
Were adults of larvae more heat tolerant?
Larvae
What prevents protein aggregates in larvae?
Constitutive HSP expression was sufficient enough to prevent irreversible protein aggregation
What is the difference between other animal HSP expression and the arctic midge larvae HSP expression?
In other animals, HSP are only expressed as a stress response
In the arctic midge larvae, HSPs are constantly expressed
Is the HSP expression is arctic midge larvae maximally or minimally expressed?
Maximally expressed
HSP expression can not be further up-regulated and additional thermotolerance cannot boost HSP expression
Why is there a difference between larvae and adult HSP expression?
Difference in thermal stability of the niches occupied by the two stages
Larvae stage is under rocks and soil so has a more stable environment
Adult forms have great temperature variability climbing over rocks
What are HSPs thought to be used for in larvae?
In cold stable environments, used as chaperones facilitating the proper folding of proteins at low temperatures
Chaperones also needed to prevent protein aggregates being formed due to high stress environments
When was the Ediacaran period?
543 million years ago
What are some hypothesised reasons for the Cambrian explosion?
Steep rise in oxygen
Development of some key evolutionary innovations e.g. vision
Small increase in oxygen crossed an ecological threshold enabling predators to emerge. This set of an evolutionary arms race that led to complex body types and behaviours
