Types of metamorphosis

2. STARTER : LABEL THE LIFE CYCLE CATERPILLAR , PUPA , EGGS C A B

3. STARTER : LABEL THE LIFE CYCLE CATERPILLAR , PUPA , EGGS C : EGGS A: CATERPILLAR B : PUPA

4. LEARNING OBJECTIVES • List the steps of incomplete metamorphosis. • Compare and contrast external and internal fertilization

5. TYPES OF METAMORPHOSIS • Metamorphosis is of two types • Complete metamorphosis • Incomplete metamorphosis Today we will learn about Incomplete Metamorphosis

6. INCOMPLETE METAMORPHOSIS • Some insect species, including grasshoppers, termites, and bedbugs, go through incomplete metamorphosis. • During incomplete metamorphosis the animal goes through three stages that occur gradually.

8. NYMPH STAGE • Young grasshoppers, for example, take on the nymph body form after hatching from eggs. • A nymph is similar to an adult form, but it is smaller and lacks wings and reproductive structures. • There may be several different nymph stages before the animal becomes an adult.

9. SHEDDING STAGE • Because it has a rigid exoskeleton, an insect cannot grow gradually like a mammal. • Instead, it sheds its hard skeleton all at once to make room for a larger body

10. The old exoskeleton being shed off

11. Grasshoppers go through five shedding stages before they reach adulthood. • During each stage, the wings emerge a little bit more. • By the time the grasshopper reaches its final stage, the adult body form is complete.

13. WHAT IS FERTILIZATION • Fertilization is the mixing of the male gametes called Sperms and the female gametes called Ovum to produce an offspring • Fertilization can occur outside the body or inside the body

14. EXTERNAL FERTILIZATION

16. Male salmon, for example, prepare for fertilization by finding a section of gravel in a lake bed. • The female digs a shallow nest in the gravel and releases her eggs. Once the eggs are in place, the male releases sperm over them in the water. • This joining of egg and sperm outside the female’s body is called external fertilization.

17. DISADVANTAGES OF EXTERNAL FERTILIIZATION • External fertilization is a high-risk process. Ponds, lakes, rivers, and oceans contain vast amounts of water. The chances of sperm cells finding and fertilizing the egg cells are decreased in large amounts of water. • Many sex cells are lost, and some are eaten by other animals. • The sex cells can also be exposed to extreme temperatures and pollution in the water.

18. INTERNAL FERTILIZATION • Reptiles, birds, and mammals use internal fertilization. • Fertilization occurs inside the female. • Internal fertilization increases the chances of fertilization and the offspring’s survival.

19. It protects sex cells and fertilized eggs from drying out. It also protects them from the dangers of harsh environments and other organisms. • Since the chances of fertilization occurring are much greater with this method than through external fertilization, fewer eggs need to be produced.

20. PLENARY • Which stage is depicted in the image? • Pupa • Incomplete Metamorphosis • Shedding Stage • Both B & C

21. LIVE WORKSHEET • https://www.liveworksheets.com/ay697356hn • https://www.liveworksheets.com/eo245496yo

22. WORKSHEET • State whether TRUE or FALSE • The union of eggs and sperms outside the female body is called External Fertilization ____________ • When fertilization occurs inside the female body it Is called Internal fertilization __________

23. WORKSHEET • Fill in the blanks • A nymph is similar to an adult form, but it is ____________ and lacks wings • This joining of egg and sperm outside the female’s body is called _________________.

24. WORKSHEET • Label the phases of life cycle correctly A : ______________ B : _______________ A B