Unit notes and practice questions
Everything here is for unit 10 of the Grade 12 Agriculture textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.
The cards filed under this chapter on the Grade 12 Agriculture page. Open one at a time.
When you use it
Use when describing the internal and external physical adaptations of bony fishes (teleosts).
Watch out
Fin rays do not connect directly to the spine, except for the caudal (tail) fin.
Drafted from Grade 12 Agriculture, pages 182-200, then checked twice before it went up
When you use it
Use when evaluating fishery management decisions regarding fish stocking and ecosystem preservation.
Watch out
Never introduce Lates niloticus outside its natural habitat because it is carnivorous and destroys native fish populations.
Drafted from Grade 12 Agriculture, pages 182-200, then checked twice before it went up
When you use it
Use to categorize Ethiopian indigenous fish species based on their evolutionary origin and river basin distribution.
Watch out
Nilotic forms are abundant in the Nile basin but are almost entirely absent from the Awash basin and northern rift valley lakes.
Drafted from Grade 12 Agriculture, pages 182-200, then checked twice before it went up
10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.
Question 1
What is the term used to describe the farming of aquatic organisms?
Answer: B Aquaculture
Why
According to the textbook, aquaculture is defined as the farming of aquatic organisms.
Question 2
Which local name is commonly used in Ethiopia for the Nile tilapia (Oreochromis niloticus)?
Answer: A Qoroso
Why
Oreochromis niloticus belongs to the family Cichlidae and is commonly known in Ethiopia as Qoroso, St. Peter fish, or Chogofe.
Question 3
What is the main function of the swim bladder in bony fishes?
Answer: C To maintain a constant depth in the water column
Why
The textbook states that bony fish have a swim bladder which helps them maintain a constant depth in the water column.
Question 4
Which physical characteristic easily distinguishes the catfish Clarias gariepinus (Ambaza)?
Answer: C An elongated body and long hair-like barbels around the mouth
Why
Clarias gariepinus can be easily recognized by its elongated body and long hair-like barbels around its mouth.
Question 5
According to the textbook, how many indigenous and exotic fish species are found in the Ethiopian fish fauna?
Answer: A 153 indigenous and 10 exotic species
Why
The Ethiopian fish fauna consists of 153 indigenous and 10 exotic species.
Question 6
Why is it NOT recommended to introduce Nile perch (Lates niloticus) into water bodies outside its natural habitat?
Answer: B It is carnivorous and preys on other fish
Why
Lates niloticus is carnivorous on other fish, so it should not be introduced into water bodies outside its natural habitat.
Question 7
The indigenous freshwater fish fauna of Ethiopia is composed of which three forms?
Answer: B Nilo-Sudanic forms, East African highland forms, and Endemic forms
Why
Ethiopian indigenous freshwater fish fauna is a mixture of three forms: Nilo-Sudanic forms, East African highland forms, and Endemic forms.
Question 8
How many pairs of gills do bony fishes have, and what structure protects them?
Answer: C Five pairs protected by an operculum
Why
Bony fishes have five pairs of gills protected by an operculum.
Question 9
How many endemic fish species and subspecies are found in Ethiopia?
Answer: B 38 species and 2 subspecies
Why
The endemic forms are very few in Ethiopia, comprising about 38 species and 2 subspecies.
Question 10
Which three carp species belonging to the family Cyprinidae were introduced into Ethiopian water bodies like Koka and Fincha dams?
Answer: A Common carp, grass carp, and silver carp
Why
The three introduced carp species belonging to the family Cyprinidae are Common carp, grass carp, and silver carp.
The app holds 12 questions on this unit, marked as you go. These are the first 10.
Unit 10 runs from page 191 to page 209 of the Ministry of Education edition.
Ministry of Education edition, English, 302 pages
Temari turns this chapter into timed practice and marks it as you go, with an AI tutor to explain anything that did not land.
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