Multicellular Organisms

Multicellular Organisms

Watch the video... and answer the questions.

Multicellular OrganismsMulticellular organisms are organismsmade up of many different cells.

Reproduction Relay!How many words related to reproductioncan you remember?ReproductionReproduction is the production of newmembers of a species.

If organisms fail to reproduce the speciescould become extinct.

This can happen sexually or asexually.

ReproductionTo reproduce sexually, sex cells (gametes) are required.

Draw a labelled diagram of a sperm cell and an egg cell in your jotter.

Gametes

FertilisationIn order for reproduction to be successful, fertilisation must take place.

Fertilisation occurs when the nucleus of the sperm fuses with the nucleus of an egg cell to produce a zygote.

A zygote is the first cell formed immediately after fertilisation.

Reproductive SystemsYou have been given diagrams of the male and female reproductive systems.

Label these as much as you can using your knowledge from S1/2.Question time!Name the two main ways in which reproduction can take place.Give another name for sex cells.State one similarity and one difference between an egg cell and a sperm cell.Describe what happens during fertilisation.Name the cell which is formed as a result of fertilisation.

Reproduction Recap

Reproduction Recap

Watch the video clip...What are the main steps in the process of fertilisation?

FertilisationUsing the sheet provided try to complete the diagram by labelling the steps correctly.Internal FertilisationInternal fertilisation occurs when the sperm and egg meet inside the females body.

It is essential the fertilisation in land animals takes place internally since there is no water outside to carry the sperm to the egg.

The Developing EmbryoAfter fertilisation the zygote begins to move along the oviduct and divide by doubling.

It then implants in the side of the womb.

The Developing EmbryoAs the embryo develops it relies on the placenta.

Use your knowledge from S1/2 to complete the sheet about the function of the placenta.One thing you have learned today...External FertilisationExternal fertilisation occurs when the sperm and egg meet in the water surrounding the parents.

This occurs commonly in fish.

Internal vs External FertilisationUse the table provided to compare internal and external fertilisation.Internal vs External FertilisationInternal FertilisationExternal FertilisationExamples of organismsFertilisation takes place inside or outside of the mothers bodyInside mothers bodyOutside the mothers bodyFertilised eggs released in to water or stay inside the motherSperm sprayed on to the eggs or sperm placed inside motherFew or very many eggs producedYoung develop inside or outside mothers bodyMost or some of the eggs get fertilisedMost or few of the offspring (babies) survive Eggs or offspring (babies) looked after, or not looked after by parentsParents build a nest or no nestProblem solving skills.The Developing EmbryoPlot a graph to demonstrate the development of the zygote into an embryo.Time (mins)Number of Cells0 1302604908120161503218064Problem Solving StationsWork your way around the stations practicing your problem solving skills.

You have 10 mins at each station.Sexual Reproduction in Plants

Watch the video clip...What are the main structures found in a flower?

TaskYour task is to dissect the flower and label the different structures accurately.

Match the structures to their functions using the sheet provided.Asexual ReproductionDoes not involve sex cells or fertilisation.

Only involves one parent.

The offspring are genetically identical to the parent

Asexual Reproduction - ExamplesBacteria are one example of asexual reproduction

Asexual Reproduction - ExamplesTubers (potato), bulbs (garlic) and runner (strawberry) plants are other examples of asexual reproduction

Asexual Reproduction - ExamplesStarfish and sea anemones are other examples of asexual reproduction

Sexual vs AsexualSexualAsexual