Report on D

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Report on D

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Online Lesson #4

Salmons

5 facts about Salmons

Largest and smallest
The largest species of salmon is the Chinook salmon, which is 1.5 m. The smallest species is the Masu or Sema salmon, which has a length of 71 cm.

Young Salmons
Newly hatched salmon with a yolk sac still attached are called alevins. When the yolk sac disappears, they are called fry. Until they are about a year old, they are called parr; 1- to 5-year-olds are called smoults.

Diet
Young salmon feed on microscopic animals and plants. As they get bigger, their diet includes insects and worms. By the time they are adults, they are eating small fish and crustaceans.

Migration
Salmon will hatch in freshwater, go to saltwater as smoults, and then return to freshwater in order to spawn and then die.

Misconception
Although legend claims that adult salmon return to the exact spot they were hatched from in order to spawn, there is no way to prove this.

Behavioural Adaptation

(Reproduction)

Salmons swim back to freshwater streams to spawn. They hurriedly swim 20 to 30 miles per day, without eating, against the current, leaping over waterfalls and rocks. The salmons will not stop till they reached their destination.

How does this adaptation benefit its predator?

After they spawn, they drift downstream and die. Their dead bodies provide food to many species of animals and also provide minerals to the trees.

Why is there a need for the females to spawn about 3000-15000 eggs in 1 run?

Just in case there is an inappropriate water flow. Appropriate water flow must continue after spawning; too much water may excavate the nest, while too little can reduce survivorship by raising water temperature and reducing oxygen flow. So, this is to prevent their species to extinct.

Online Lesson #3

Arctic Fox

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Online Lesson #2

P.S. There are 2 slides.

OL#2

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Online Lesson #1

1. Identify the organism(s) that are producers?
The organisms are wheat, clovers and dandelion.
2. Identify the organism(s) that are consumers?
The organisms are the grasshoppers, mouse, rabbit, caterpillar, frog, snake, owl and hawk.
3. List some of the food chains by writing the organism's name and drawing a line that points to the next organism in the food chain.
Wheat –> Mouse –> Snake –> Owl
Clover –> Rabbit –> Hawk
Dandelion –> Caterpillar –> Frog –> Snake –> Owl
4. How many food chains can you find in the above food web?
There are 8 food chains in the above food web.