Fish Farming and Selective Breeding Flashcards
Why are fish being farmed?
To increase the amount of fish and of protein food available
Why are fish farmed in cages in the sea?
Stops them from using as much energy swimming about Protects them from interspecific predation - being eaten by other animals like birds and seals
The fish can be selectively bred to produce less-aggressive, faster-growing fish
How does fish farming in cages in the sea help improve the quality of food?
The fish are fed on a diet of food pellets that are carefully controlled to maximise the amount of energy they get - the better quality the food is, the quicker and bigger a fish will grow, which is good as they are a source of protein
How does fish farming in cages in the sea help protect fish from intraspecific predation?
Young fish are reared in special tanks to ensure as many survive as possible - they are provided with regular food and kept separate from bigger fish
What is intraspecific predation?
When organisms eat individuals of the same species
How can disease be controlled in fish farming in cages in the sea?
Fish kept in cages are more prone to disease and parasites e.g. sea lice - can be controlled with pesticides or biological pest control e.g. wrasse, which eats lice off the salmon
Why are fish farmed in tanks?
The water can be monitored e.g. temp, pH, oxygen level
It’s easy to control how much and the quality of food supplied
The water can be removed and filtered to get rid of waste food and fish poo - keeps the water clean for the fish and avoids pollution wherever the water ends up
What are the advantages of fish farming?
Water can be monitored
Diet of fish controlled
Protected from interspecific and intraspecific precautions
Selective breeding can be done to improve the quality of the fish
What are the disadvantages of fish farming?
Potential spreading of disease is greater than normal because the fish are closer together
Antibiotics used to treat disease in fish could affect humans that eat the fish
Water pollution caused by animal faeces and food pellets
Pesticides used to kill fish parasites are harmful to other non-harmful species of invertebrates
What is selective breeding?
When humans use the principles of natural selection to produce animals or plants with desired characteristics
Example answer of how plants with desired characteristics can be developed by selective breeding
1) find two, healthy crop plants of the same species with the desired characteristics e.g. disease resistance
2) isolate the flowers then perform cross-pollination, transferring the pollen of one of the plants to the stigma of the other
3) when seeds are produced, plant them and allow them to grow
4) observe the characteristics of the offspring
5) repeat several times until you obtain an ideal offspring
Example answer of how animals with desired characteristics can be developed by selective breeding
1) find two, healthy fish of the same species with the desired characteristics e.g. large size
2) isolate the fish and breed them
3) allow the eggs to hatch and the young fish to grow
4) record the sizes of the offspring
5) choose the offspring with the desired characteristics, isolate them and breed them
6) repeat many times to ensure that all the offspring have the desired characteristic
What is the general process of selective breeding?
1) from your existing stock select the ones that have the best characteristics
2) isolate and breed them with each other
3) select the best offspring and breed them together
4) continue this process over several generations, and the desirable characteristic gets stronger and stronger. In farming this will give the farmer gradually better and better yields
What can be benefits of selective breeding?
Can increase the productivity of cows e.g. high milk yield
Increasing crop yield
Good health and disease resistance
Increase in speed, fertility, good mothering skills
More attractive flower, nicer smell
How is selective breeding different from natural selection?
1) selective breeding is carried out by humans
2) selective breeding can be sped up, so is a faster process
