Reproduction (non-mammalian) Flashcards
How many ovaries do female birds have?
One (two in some raptor species).
How does colony size affect testis size in birds? What does this indicate?
Testis size increases with colony size.
Greater sperm competition in colonies.
Where is the bed is the eggshell formed?
Uterus or shell gland.
Where in the bird is the yolk produced?
Ovary.
What hormone stimulates the release of the yolk?
LH (luteinizing hormone)
What is the first sign of sexual maturity in chickens?
Comb development.
Why do domesticated chickens lay eggs all year round?
Changes in the gene that encodes for the thyroid stimulating hormone receptor (effects perception of day length).
What are gyandromorphs?
Individuals showing both male and female characteristics.
Name the 3 reproductive modes in fish.
Viviparity
Ovoviviparity
Oviparity
Which amphibians produce sperm packets?
Newts and salamanders.
How do females utilise sperm packets?
They are taken up by the cloaca and eggs are fertilised as they pass through the cloaca.
Which group of amphibians fertilise eggs externally?
Caecilians.
What is the PLF in reptiles?
Pre-laying fraction.
Duration of retention of eggs in utero, relative to the total length of embryonic development.
Which type of reptiles have a pair of hemipenes?
Squamates (including snakes and lizards), these are often covered in spines/hooks to remain attached to the female.
Give evidence for sperm storage in some reptiles.
Data show female turtles can store sperm for many years and it will still be viable.
How is climate change affecting temperature-dependent sex determination?
Many species having to nest earlier to preserve sex ratio.
Which reptiles use TSD?
All crocodiles
All snakes
2 extant species of tuatara
Some lizards
How does the gonad develop before TSD in reptiles?
As a bipotential primordium (genital ridge) that’s identical in all embryos.
Which groups of reptiles exhibit asexual reproduction in captivity?
Snakes and lizards- Offspring are half clones of their mother.
What is special about the southeast Asian butterfly lizard?
There are only females of this species that reproduce via cloning.
What is the equivalent of testes and ovaries in insects?
Ovarioles and testicular follicles.
What is a spermatotheca in insects?
Part of the female reproductive system where sperm from the male is stored.
How does sperm enter the egg after chorion formation in insect reproduction?
There is a small hole in the chorion called the micropylar region which allows the sperm entry into the egg.
Give 4 ways insects are brought together to mate.
Swarming
Use of pheromones
Colour and movement to attract a mate.
Sound- mosquitos, crickets etc.
How is sperm transferred in insects?
By means of spermatophore.
When are eggs fertilised in insects?
While passing down the oviduct and vagina.
How are some male damsel flies adapted to optimise mating success?
Have a penis morphology that removes or repositions sperm of a previous mate before depositing their own.
Which 2 hormones control egg maturation in insects?
Ecdysteroids and juvenile hormone.
How does JH work in larval-adult growth?
High amounts - larva to larva moults
Low amounts - pupation
No LH - formation of the adult insect.
Name and describe some female accessory gland secretions in insects.
Adhesive- surrounds eggs and acts as a glue to stick them to a substrate (leaves etc)
Ootheca- jelly-like materials that harden to form a protective case.
Name 2 egg deposition methods?
Random
Highly selective - underwater, near water, on/in host insect, on back of a male.
