Terrestrial VS Aquatic Food Production

Next, is a comparison between terrestrial and aquatic food production.

Terrestrial:

• Food harvested from 1st or 2nd trophic levels thus more energetically efficient.
• Solar energy capture (GPP) more efficient.
• Energy transfers between trophic levels not as efficient. 

Aquatic:

• Most food is harvested from higher trophic levels, thus not as efficient
• Solar capture (GPP) not as efficient due to absorption of sunlight by water
• Energy transfers between trophic levels fairly efficient.

Farming and production systems

There are several types of farming systems

1. Subsistence: provision of food for family and their community; little or no surplus; mixed crops; extensive use of human labor; low use of fossil fuels, chemicals, and capital; little technology.

2. Commercial: large profit generating scale; maximized yields, monocultures; high levels of technology, energy, and chemical inputs.

MEDC vs. LEDC

MEDC (Most Economically Developed Countries)

• In many MEDCs, the cost of staple food items is relatively cheap. 
• Most people make purchases based on taste and preference.
• Produce seasonality has mostly disappeared due to globalization. This has also allowed for a greater international variety in most supermarkets.
• In MEDCs the average caloric content per capita per day of food is 3314 calories. In the USA specifically, this number is 3774 calories.

LEDC (Least Economically Developed Countries)

• In LEDCs, many staple food items may not be always affordable as prices fluctuate. 
• People tend to make purchases based on nutritional need and affordability.
• Political and economic agendas can affect food production (e.g. cash cropping)
• Even if food crops are not used as cash crops, food production is still impacted since arable land is being occupied all the same.
• In LEDCs the average caloric content per capita per day of food is 2666 calories. In Eritrea this number is 1512 calories.

Demographic Transition Models

Demographic Transition Models describes the pattern of decline in mortality and natality (fertility) of a country due to social and economic development.

Can be describes as a 5-stage model:

1. Pre-industrial
2. LEDC
3. Wealthier LEDC
4. MEDC stable
5. MEDC population decline.

Type of population pyramid shapes

There are several types of population pyramids and are divided into four stages, which are:

Stage 1: Expanding - High CBR, rapid fall in each upward age group due to high CDR, short life expectancy.

Stage 2: Expanding - High CBR, fall in CDR as more individuals live to middle age, slightly longer life expectancy.

Stage 3: Stationary - Declining CBR, low CDR, more individuals live to old age.

Stage 4: Contracting - low CBR, low CDR, higher dependency ratio (those that cannot work), longer life expectancy.