Humans in the Biosphere Chapter 6 Humans in the Biosphere

A Changing Landscape “Earth is an Island” All organisms- including humans -that live on Earth share limited resources & depend of them for their survival. Natural ecological processes sustain these resources (water, carbon, nitrogen cycles) To protect these resources – we must understand how humans interact with the Earth

Humans and the Biosphere We as humans depend on chemical cycles (H20, C, N) to provide: a. breathable air b. drinkable water c. fertile soil d. storage & recycling of nutrients We must understand how human activity affects these cycles

Human Activities that Affect the Biosphere Hunting & gathering Agriculture Industry Urban development Human activity has become the most important source of environmental change on the planet. We do not fully understand how these activities affect our ecosystems

Human Activities Hunting and gathering Agriculture Industrial growth that have changed the biosphere include Hunting and gathering Agriculture Industrial growth Urban development may have once caused often relies on the methods of the have resulted in Extinctions of large animals Green revolution High standard of living Increased pollution which increased Food supply Pesticide use Monoculture use

Renewable Resources Can regenerate or can be replenished Not always unlimited Example: - Water can become limited by drought or overuse Human activity can affect the quality of renewable resources such as: - land, forests, fisheries, air & freshwater

Nonrenewable Resource Cannot be replenished by natural processes When they are depleted – they are gone forever Example: - coal - oil - natural gas (fossil fuels)

Sustainable Development Way of using natural resources without depleting them Provides humans with what they need without causing long term environmental harm This can have a positive impact on the environment we create for ourselves & future generations

Biodiversity 2. industrial products The sum of the genetically based variety of all organisms in the biosphere Basically, how all living things are so different!!! Greatest natural resource The many different species provides us with: 1. food 2. industrial products 3. medicines (painkillers, antibiotics, heart, antidepressants & anticancer drugs) When biodiversity is lost, potential sources of material with significant value to Earth & mankind may be lost with it

Types of Diversity Ecosystem Diversity: Examples: Variety of habitats, communities, and ecological processes in the living world Examples: habitats ecological processes 1. deserts 1. water cycle 2. mountains 2. carbon cycle 3. rain forests 3. nitrogen cycle 4. oceans 4. phosphorus cycle

Types of Diversity Species Diversity Genetic Diversity Refers to the # of different species in the biosphere Scientists have identified & named about 1.5 million species They estimate millions will still be discovered Genetic Diversity Refers to the total of all the different forms of genetic information carried by all organisms living on Earth today (DNA)

Threats to Biodiversity Altering habitats Hunting to extinction Introducing toxic compounds into food webs Introducing foreign species to new environments