Homing Flashcards
What is homing?
It is a precise means of orientation or navigating back to a particular location which could be their home
How does salmon homing work?
Juveniles leave natal stream to return to sea
What do salmons do when they lay their eggs?
The salmon lay their eggs in oxygenated rivers where they develop over the winter
As they develop they go under smolitification where they prepare themselves to go into the sea
Around 18 months later the salmon return to the same river to lay their eggs
What is the olfactory imprinting hypothesis in salmon?
Haslar developed the idea that salmon homing used smell from their stream which they imprinted on while they are developing
What happens during salmons smolitification?
They looked at the olfactory epithelium in fish at smolitification. They found that there was a high level of thyroid hormones T3 and T4.
Salmon experiment on thyroid hormones: T3 and T4
They injected salmon before smolitfication with. Thyroid hormone to stimulate the release of t3 and t4
They found that these fish imprinted to an odorant cue but those who where injected with saline did not
What did Lena and Nevis do with T3
They injected epithelium with elevated T3
It caused an increase in mitotic cells which shows that the particular structure that is responsible for smelling different water bodies develops during smolitification
What experiment did they do to support olfactory imprinting - haslar and wispy?
They used blunt noseminnose and trained them to discriminate different water types using a reward and punishment
They damaged the nasal sacs which lead to a lack of discrimination
They also removed organic compounds of water and they loss discrimination
What was the experiment hasler did for salmon transplantation
He got fish going through smoltification and imprinted a group with normal water and morphiline
What happened to the fish that went through somltification with morphiline
Haslar scented the river with morphiline after 18 months
The fish that imprinted to the tributary returned if the tributary was scented - this means that its the oderant cue that made the fish come back as morphiline is not present in water
How does pigeon homing work?
Pigeons use magnoreception to navigate when its cloudy
They use a sun compass when it’s clear
What experiment did they do on pigeon and homing
They had pigeons in aloft and released them out at sea well a way from their loft and used GPS tracking to see their flight paths
They used the course of motorways to find their way back to their home
There are instances where bird move away from the road as their loft is in a different direction
