Environmental Effect on Development. Flashcards
Can the environment can play a role in determining the phenotype of an organism?
Yes.
What is phenotypic plasticity?
The ability of an organism to take information from the environment and change as a result.
Phenotypic plasticity can result in what kind of changes?
Developmental, i.e. structure or function.
Or behavioural changes.
What is developmental plasticity?
When phenotypic plasticity occurs in the developmental or larval stages of an organism.
What is polyphenism?
A discontinuous phenotype that results due to influences from the environment.
What is diet induced polyphenism?
Polyphenism that arises due to what the organism eats during development.
What is predatory induced polyphenism?
This occurs when predators in the environment cause phenotypic changes.
What influences predatory induced polyphenism?
Because predators release hormones called kairomones.
These are detected by individuals and will cause a change in phenotype.
Why will organisms change their phenotypein the presence of a phenotype?
These changes are designed to increase survival of the prey animal.
How can changes in developmental timing be induced?
Due to the presence of a predator.
What is temperature dependent sex determination?
When the sex of an organism is determined by the temperature of the embryo at certain moments during development.
What are the phenotypic differences between worker bees and queen bees?
Worker honey bees tend to be very small.
The queen is much larger in size than the worker bee.s
Why is the queen larger than the worker bees?
She has ovaries in her body so that she can keep reproducing.
Which bees are capable of reproducing?
The queen bees are the only bees that can reproduce.
How do the phenotypic differences between the queen bee and the worker bees arise?
Because of what they are fed as larvae.
What are queen bees fed as larvae?
Royal jelly.
What do worker bees get fed as larvae?
A protein called casein that does not produce the same amount of growth as royal jelly.
What protein does royal jelly contain?
Royalactin.
How does royalactin influence growth?
It binds to EGF receptors (epidermal growth factors) in the developing larvae which stimulates cell growth and development.
How does royalactin stimulate fertility?
It stimulates the juvenile hormone which allows the queen bee to become sexually reproductive.
What is the species name of the caterpillar that has diet induced polyphenism?
Nemoria arizonaria.
What does the diet induced polyphenism in the caterpillar help it to do?
Be camouflaged from predators.
Caterpillars that are born in spring eat what?
Oak flowers (catkins).
Caterpillars that are born in summer eat what?
Oak leaves.
What is the diet that induces a larger size in the caterpillars?
Oak flowers (catkins).
Caterpillars that eat catkins will look like what?
A fuzzy coating with brown dots that mimics catkins.
Caterpillars that eat oak leaves will develop what?
Very small twigs.
What is it between the caterpillars diet of catkins and oak leaves that causes the change in phenotype?
The tannins in the oak leaves.
Will all dung beetles develop a horn on the head?
No.
What will cause the development of a horn on the head of a dung beetle?
The quality of the dung that the dung beetle was provided for the larvae.
What kind of dung will cause the development on the head of a dung beetle?
Good quality dung.
Why does good quality dung cause the horn to develop?
The triggering of the juvenile hormone once the larvae reach a certain size.
How does poor quality dung influence the phenotype of a dung beetle?
There won’t be as much growth and the dung beetle will not develop a horn.
The presence or absence of a horn will affect what about an adult dung beetle?
Its behaviour.
Can horned males or non horned males dig holes?
Non horned males.
When a horned male mates with a female, what will he do?
The female will dig a tunnel under a dung heap and will lay the eggs in this tunnel.
Horned males will guard the tunnel and defend the tunnel against other males.
What is another name for hornless males?
Sneaker males.
How do hornless males mate with females in a tunnel?
They will dig a tunnel past the guarding male and link up with the female.
How many matings are estimated to be done by sneaker males?
50%.
What affects the phenotype of the desert locust?
Whether they have hatched during a dry period or a wet period.
If locust eggs hatch during a period of drought, what phenotype will the offspring have?
Solitary locusts.
What is the phenotype of a solitary locust?
Green in colour, small and has under developed wings.
If the locusts hatch during a wet period, what will the phenotype be?
They are said to have a gregarious phenotype.
What is the gregarious phenotype?
Brown in colour, larger and they will develop long wings.
Which phenotype of locusts will release a pheromone that causes them to swarm?
Gregarious locusts.
What causes the differences between the gregarious phenotype and the solitary phenotype?
If the soil is moist, then it will be easier for the females to lay their eggs.
There is more food for the juveniles, so the density of eggs is very high.
What do the juvenile gregarious locusts do when they hatch?
They will bump into each other which stimulates the phenotypic changes due to a chemical signal.
Why doe juvenile solitary locusts not swarm?
Their eggs hatch in a lower density which stops them from bumping into each other.
What are rotifers?
Small protozoa like creatures that live in ponds.
How will rotifers develop without the presence of predators?
If there are no predators present then they will lack spines on their body.
How will rotifers develop in the presence of predators?
They will develop large spines that come out of their body.
What is it that predators produce to induce a change in phenotype in rotifers?
Kairomones.
How did researchers prove that kairomones were responsible for inducing a change amongst their prey?
Researchers placed rotifers in water which had previously held predatory crabs.
Even though there were no crabs in the water, the phenotypic changes were still induced.
What is an opercula?
The hole in the mouth of a barnacle.