UNIT 4

1. UNIT4 The reproduction function POST-EMBRYONICDEVELOPMENT Natural Science 2. Secondary Education

2. UNIT4 Post-embryonic development POST-EMBRYONICDEVELOPMENT can be DIRECT INDIRECT Click on each box to find out more Natural Science 2. Secondary Education

3. UNIT4 Post-embryonic development Direct development • The new-born individual is similar to the adult, only smaller. • Its development consists of: • Growth. • Maturity of the organs. • Boars develop this way. Natural Science 2. Secondary Education

4. UNIT4 Post-embryonic development The direct development of the boar 2 1 During the first months of its life, the lines disappear and its fur turns a reddish colour. The baby is born with a similar appearance to the adult: the difference is in its size and fur, which has some characteristic lines in the back. 3 As it grows, the boar’s fur gets darker becoming brown as an adult. Go back to the Start menu Natural Science 2. Secondary Education

5. UNIT4 Post-embryonic development Indirect development • In indirect development, the new-born individual, the larva, looks completely different from the adult. • The transformation from larva to adult takes place through a series of transformations called metamorphosis. • In metamorphosis, the larva loses some organs and generates others. • Ladybirds develop this way. Natural Science 2. Secondary Education

6. UNIT4 Post-embryonic development The metamorphosis of the ladybird After fertilisation the ladybird lays eggs. 1 2 When the embryo has completely developed, hatching takes place. Fertilisation 4 The larvae form a cocoon where they will complete their metamorphosis. 5 3 Once the transformation is complete, an adult individual emerges. The larvae that are born are very different from the adults. Go back to the Start menu Natural Science 2. Secondary Education