Reproductive Strategies GCE BIOLOGY BY2 Reproductive Strategies

Place your vote by clicking the ‘Chicken’ or ‘Egg’ button Which Came First? Which came first? 20 19 18 17 OR 16 15 14 13 12 The Chicken? The Egg? 11 10 9 Place your vote by clicking the ‘Chicken’ or ‘Egg’ button 8 7 6 5 4 Be prepared to justify your choice 3 2 1 Chicken Egg

Simple unicellular organism Reproduction What type of reproduction does this animation represent? Simple unicellular organism Hint: Identical offspring to the parent is produced. Mitosis is involved. Next: What type of reproduction?

What Type of Reproduction? Drag the corresponding numbers to the appropriate circle to determine if the statement relates to sexual or asexual reproduction: Involves the production of haploid gametes (n) (sex cells with one copy of each of the parents’ chromosomes) 1 1 2 2 Only involves mitosis 3 3 Produces offspring showing variation from the parent 4 4 Occurs when unicellular organisms, such as amoeba reproduce Asexual Sexual

Outline of Mitosis Diploid parental cell (2n) Duplication of a Chromosome is Followed by nuclear division Diploid daughter cells (2n) Next: Outline of meiosis

Each chromosome duplicates to form two Outline of Meiosis Haploid gametes maternal chromosome paternal chromosome 2 chromatids centromere (n) Meiosis II Meiosis I Each chromosome duplicates to form two Pairs of chromatids Diploid parent cell (2n) Next: Comparison of mitosis and meiosis

Diploid daughter cells Comparison of Mitosis and Meiosis Diploid parental cell 2n 1st meiotic division (meiosis I) First division 2nd meiotic division (meiosis I) Diploid daughter cells 2n n n n n Haploid gametes

The Human Life Cycle This is an example of a diploid life cycle 2n 2n mitosis 2n mitosis meiosis n n meiosis zygote 2n fertilisation This is an example of a diploid life cycle

Human The Human Life Cycle Drag the labels provided to create the Human life cycle fertilisation sex organs Human zygote gametes adult

diploid haploid Plant Reproduction sporophyte spores mitosis mitosis gametophyte zygote male gamete fertilisation mitosis haploid female gamete

Reproduction Task: Compare the life cycle shown below.

Fertilisation Compare fertilisation in a fish and humans Human A strong possibility that many of the eggs will not encounter sperm A lot of waste with both sexes producing a large number of gametes Fertilisation happens inside the body Fish An intromittent organ required to transfer sperm into the female’s body

Fish The Life Cycle of a Fish adult juvenile spawning fry eggs Larval fish

The Frog Metamorphosis: Frog Drag the images provided to create the life cycle of a frog The Frog

The Insect Life Cycle Many insects change form during their lifetime - this is called metamorphosis. They do this in one of two ways: a) Complete metamorphosis b) Incomplete metamorphosis Click on the images above for a larger version of the life cycles Next: The fly life cycle

The Butterfly The Insect Life Cycle butterfly (adult) pupa eggs larva Back Next larva

(showing rudiment of wings) The Insect Life Cycle locust (adult) The locust eggs instars (showing first wings) nymph (showing rudiment of wings) Back

The Fly The Insect Life Cycle Adult Fly Pupa Eggs 3rd larval stage 1st larval stage 2nd larval stage

Metamorphosis Choose an insect and drag it to the ‘insect’ box below. Decide what type of metamorphosis it has, then complete its life cycle by dragging the appropriate labels into the correct position on the diagram: incomplete metamorphosis complete metamorphosis pupa adult insect egg larva chrysalis metamorphosis nymph