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Grade 12 evolution and fungi practicals

• In this activity you will be required to answer the given multiple choice questions, the format of answering them is you only select the most correct answer and circle it, you can only circle one choice per question.

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Question 1

• In The wings of a butterfly and the wings of a bird are examples of …

A: homologous structures.

B: vestigial structures.

C: analogous structures.

D: common ancestry

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Question two

• Which ONE of the following is an acceptable explanation based on Darwin's theory of evolution?

A: Humans evolved from apes

B: A mother who had her appendix removed will give birth to Children without an appendix

C: An increasing number of TB-causing bacteria are resistant to antibiotics because those that are resistant are able to survive and reproduce

D: Giraffes have long necks because the previous generation stretched their necks to reach the leaves in tall trees.

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Question 3

• Which ONE of the following refers to development in some birds where the eggs hatch outside the body and the young are born immobile and totally dependent on its parents?

A: Vivipary and precocial development

B: Ovipary and altricial development

C: Vivipary and altricial development

D: Ovipary and precocial development

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Question 4

• Which ONE of the following increases the chances of survival of a species?

A: Living individually

B: Living in a colony with division of labour

C: Having random breeding pairs

D: Hunting for prey with different species

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QUESTION 5

• Which ONE of the following is TRUE about seeds?

A: Protect the gametes

B: Provide the embryo with food from cotyledons

C: Develop into a fruit

D: Develop from an ovary

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Practical assesment

• In this task you are required to work in groups of 5 learner per group and follow the instructions on the report bellow then observe the reactions and submit them along with your practical report.

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PRACTICAL 2FUNGI

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FUNGI• Large group of eukaryotic organisms

• Includes microorganisms such as yeasts and moulds, and the more familiar mushrooms

• Separate from plants, animals and bacteria

• Cell walls contain chitin

• No chlorophyll – cannot make own food

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FUNGI• Important role:

– In the decomposition of organic matter

– And fundamental roles in nutrient cycling and exchange.

• Uses:– Food source: mushrooms and truffles– Leavening agent for bread– Fermentation: including wine, beer, and

soy sauce.

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EXPERIMENT 1: Bread Mould• Mold Mold is a is a fungusfungus

– Grows from tiny spores, not seedsGrows from tiny spores, not seeds– No chlorophyll, can't make their own food

• Grows & feeds on food (bread) to help Grows & feeds on food (bread) to help break it down into useful nutrients break it down into useful nutrients – Mold produces chemicals that make food

break down and start to rot– As the food is broken down into small,

simple parts, the mold absorbs them and grows

http://www.youtube.com/watch?v=zDRxB9Vw_dU

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• After a few days white cottony fuzz growing on bread

• After a few more days, turn black

• The tiny black dots are its spores, which can grow to produce more mold Rhizopus Rhizopus stoloniferstolonifer. .

http://www.exploratorium.edu/science_explorer/mold.htmlourplaceourplace.blogspot.com

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• It can be annoying to find moldy food in your refrigerator– Most foods have preservatives

• But in nature, mold is very useful – Helps food and other materials rot– Rotting things return to the soil, providing

nutrients for other living things – Mold is a natural recycler.

http://www.exploratorium.edu/science_explorer/mold.html

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EXPERIMENT 2: Yeast-air balloons

• Yeast is a fungus

• Produces gas by feeding on sugars

• A common yeast used in cooking is bakers yeast, Saccharomyces cerevisiae– Used to make bread rise – As yeast feeds on sugars in flour it releases

CO2 creating bubbles allowing dough to rise

– 1g holds 25 billion cellshttp://www.exploratorium.edu/cooking/bread/activity-yeast.html

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• After several minutes, you’ll notice the balloon standing upright

• As the yeast feeds on the sugar, it produces CO2.

• With no place to go but up, this gas slowly fills the balloon.

• Similar process happens as bread rises– CO2 from yeast fills thousands of balloon-like

bubbles in the dough. – Once the bread has baked, this is what gives

the loaf its airy texture. http://www.exploratorium.edu/cooking/bread/activity-yeast.html

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EXPERIMENT 2: Yeast Decomposition

• Yeast (a fungus) aids in the decomposition Yeast (a fungus) aids in the decomposition processprocess– It breaks down matter into different

components.

• It helps break down organisms into inorganic matter.

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• The banana with the yeast should break down faster than the one without the yeast

• May notice a slight inflation of the bag due to the release of carbon dioxide– Sugar is broken down into ethanol and carbon

dioxide.

http://utenti.quipo.it/colettisb/ipertesto-redi/redi/bananas.htm