Humans in the Biosphere

Chapter 6

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 BiosphereWe as humans depend on chemical cycles

(H20, C, N) to provide:a. breathable airb. drinkable waterc. fertile soild. storage & recycling of nutrients

We must understand how human activity affects these cycles

Human Activities that Affect the BiosphereHunting & gatheringAgricultureIndustryUrban 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

HumanActivities

that have changed the biosphere include

may have once caused often relies on the methods of thehave resulted in

which increased

Food supply Pesticide use Monocultureuse

Hunting andgathering Agriculture

Industrial growth

Urbandevelopment

Extinctions oflarge animals

Greenrevolution

High standardof living

Increasedpollution

Renewable ResourcesCan regenerate or can be replenished Not always unlimitedExample:

- 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 ResourceCannot be replenished by natural processesWhen they are depleted –

they are gone foreverExample:

- coal- oil- natural gas (fossil fuels)

Sustainable DevelopmentWay of using natural resources without

depleting themProvides 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

BiodiversityThe sum of the genetically based variety of all

organisms in the biosphereBasically, how all living things are so different!!!Greatest natural resourceThe many different species provides us with:

1. food2. 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 DiversityEcosystem Diversity:

Variety of habitats, communities, and ecological processes in the living world

Examples:habitats ecological

processes1. deserts 1. water cycle2. mountains 2. carbon cycle3. rain forests 3. nitrogen

cycle4. oceans 4. phosphorus cycle

Types of DiversitySpecies 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 DiversityRefers to the total of all the different forms of

genetic information carried by all organisms living on Earth today (DNA)

Threats to BiodiversityAltering habitatsHunting to extinctionIntroducing toxic compounds into food

websIntroducing foreign species to new

environments