Chapter 6 - Sources of Food Flashcards
What are the 4 categories of food?
crops , farm animals , dairy products , fish and seafood
what is the primary source of food
Plants
What is photosynthesis
it is a process where green leafed plants make their own food in the presence of sunlight
Where the excess food goes ?
to the roots , leaves and stems of the plants
the word equation for photosynthesis
carbon dioxide + water + sunlight + chlorophyll = sugar + oxygen
what does the excess sugar change into ?
starch
how is starch used for photosynthesis?
starch is used as evidence to show that photosynthesis has occured
What Color does the iodine turns when starch is present
iodine turns blue
pH of 0-6
acidic
pH of 7
neutral
pH of 8-14
alkaline
what does soil provide for the plants
nutrients
what does fertilisers do?
it helps to give nutrients to the soil if the soil does not have enough nutrients and helps to increase crop yield
natural fertilisers
natural fertilisers such as compost is not toxic and does not pose a threat to the environment
chemical fertilisers
chemical fertilisers are also used to increase crop yield
disadvantages of chemical fertilisers
- water contamination
- negative impact on aquatic life
- algae bloom
these chemicals are toxic and harmful for the environment and if we overuse them there can be negative impacts
what is slash and burn
slash and burn is an agricultral method where tress are cut down to clear land to grow crops
advantages of slash and burn
- cheap and fast method
- the ashes provide nutrients for the soil
- it reduces the occurence of pests and plant diseases
disadvantages of slash and burn
- haze
- soil erosion
- possible spread of fires
what are pests
they are animals ( insects / rats ) that feed on the crops and destroy them
what are weeds
weeds compete with crops for nutrients. this can decrease crop yield as there is lesser nutrients for the crops
what are pesticides
pesticides are used to kill pests. they are sprayed onto the crops but it does not harm the crops.
what are herbicides
herbicides are used to kill weeds and prevent them from competing with the crops for nutrients
the negative impacts when too much of the chemicals are used
- soil contamination
2. water contamination
what is biological methods
this is where farmers bring in the natural enemies of the pests. this helps to prevent the pests from attacking the crops
what are the advantages of using this method ?
( non chemical method )
- the crops will not be contaminated by the chemicals
2. they are not toxic and they do not harm the environment
what are the disadvantages of using this method
biological method
when too many natural enemies are introduced, it can disrupt the food chain
why do we need to improve food production
because the global human population is increasing
what is one way we can improve food production
improve plant varieties by planting good seedlings. good seedlings can make the crops bigger and better.
another way we can improve food production
improve animal varieties like milking cows . good meat , bigger farm animals, chickens to grow better eggs
what is aeroponics
it is a method where plants are in a mist of the special nutrients solution but it sprayed onto the roots
what is hydroponics
its a method of growing plants in a special nutrient solution
what are plant hormones
plant hormones are used to kill weeds and help with the ripening of the plant fruit growth.
