Overview: The chain in my lunchbox

Key messages

• Agricultural society is the basis for modern civilisation.

• The macronutrients in our food are carbohydrates (also called sugars), fat, fiber, protein, and water.  

• A food web describes the feeding connections between organisms in a community. 

Related information

Agriculture and Horticulture

• Agriculture and horticulture is the difference between there being a few million people on Earth and there being billions of people on Earth.

• Farmers learned early in the history of agriculture and horticulture that managing soil to ensure that soil conditions are ideal for plant growth is critical for healthy plant and animal growth and therefore food production.

• Providing additional nutrients in the form of fertilisers and composts allows soils to remain productive.  As crops are harvested nutrients that have been used by the growing plants are removed from the soil system and must be replaced if soil is to remain productive.

• Having a society based on survival from produce created a need to protect the investment people made in the land including the productivity of the land.

Māori land use (More information at Te Ara.)

• Early Māori were great farmers and brought with them knowledge of soils. Like modern soil scientists, they used observation and experimentation to gather data and developed processes to modify the soil.

• Māori added stones, and charcoal to lighten and to help warm the soil. The kūmara were planted into mounds (puke) to improve drainage and arranged into rows to improve access.

Nutrition

• All the food that humans eat contains nutrients that plants have taken from the soil (N, P, K) and captured from the atmosphere (C ).  As plants grow the nutrients become part of the fruit, leaves and seeds that animals and humans eat.  Those nutrients have entered the food web.

• Fruits and vegetables provide us with carbohydrates, fats, fibre and protein, as well as important vitamins and minerals.

• Protein contains carbon (C ) and nitrogen (N). It is found in food such as eggs, cheese, milk, legumes, meat and fish.

• Fats mostly contain carbon (C ). Foods that contain fats are butter, oil, nuts, meat, fish, and some dairy products.

• Carbohydrates mostly contain carbon. Whole foods that contain carbohydrates include grains, fruit, and vegetables.

• Some carbohydrates are much better for you than others.  The difference is to do with the amount of fibre or indigestible carbohydrates that are present in the food.  Carbohydrates from whole foods such as fruit, grains and vegetables contain lots of fibre, which is very good for you.

• We get lots of other important nutrients from our food such as vitamins and minerals.

Food chains and food webs

• Toxins can also enter food webs and be transferred in the same way as nutrients through food webs.

• Both energy and nutrients flow through a food web, moving through organisms as they are consumed by an organism above them in the food web. 

• A single path of energy through a food web is called a food chain.

• Plants are at the bottom of the food chain and people are at the top. No animals eat us. Unless...