Human Impacts on Ecosystems

Three activities that humans do that affect ecosystems are: building [blank_start]dams[blank_end], [blank_start]cutting[blank_end] forests, and [blank_start]converting[blank_end] natural lands.

The indirect effects of human activities are [blank_start]climate[blank_end] change due to increased [blank_start]greenhouse[blank_end] gases, [blank_start]biodiversity[blank_end] loss due to [blank_start]wildlife[blank_end] destruction, and polluted [blank_start]coastal[blank_end] environments due to increase runoff.

The name of the current geologic epoch is [blank_start]anthropocene[blank_end].

Atmosphere: Humans [blank_start]pollute[blank_end] the air with many different molecules. Increased levels of [blank_start]carbon[blank_end] dioxide are the result of burning [blank_start]fossil[blank_end] fuels and changes in [blank_start]land[blank_end] use. The increased levels of [blank_start]nitrous[blank_end] oxide are due to the increased use of [blank_start]fertilizers[blank_end]. The increased levels of [blank_start]methane[blank_end] are due to irrigated [blank_start]agriculture[blank_end] and raising of [blank_start]cattle[blank_end].

Biodiversity: About [blank_start]900[blank_end] species have become extinct in the past [blank_start]500[blank_end] years. The pace of extinction has [blank_start]accelerated[blank_end].

Cities: Human population is currently over 7 [blank_start]billion[blank_end]. This results in [blank_start]increased[blank_end] demands for land, water, food, and energy.

Coastal Habitats: These habitats have been [blank_start]exposed[blank_end] to pollution due to [blank_start]agricultural[blank_end] runoff. The runoff carries [blank_start]nitrogen[blank_end] & [blank_start]phosphorus[blank_end] into water which feeds [blank_start]plankton[blank_end]. High plankton results in [blank_start]suffocation[blank_end] of underwater organisms.

Farming: Natural land is [blank_start]cleared[blank_end] for agriculture. This results in [blank_start]increased[blank_end] levels of carbon in the atmosphere and a loss of [blank_start]biodiversity[blank_end].

Forests: Forests have been [blank_start]cleared[blank_end] for human development & agriculture. This changes [blank_start]habitats[blank_end] of other species which may lead to their [blank_start]extinction[blank_end].

Invasive Species: These species get introduced as a result of global [blank_start]trade[blank_end] and [blank_start]travel[blank_end]. They change the [blank_start]makeup[blank_end] species that are already living in that environment. Since they are newly introduced, native species have no protection against them and can die due to the [blank_start]competition[blank_end].

Mining: Mining causes [blank_start]erosion[blank_end] and pollution. They [blank_start]disrupt[blank_end] natural geochemical cycles of [blank_start]carbon[blank_end], [blank_start]nitrogen[blank_end], & [blank_start]phosphorus[blank_end].

Ocean: Overfishing [blank_start]depletes[blank_end] fish populations. Depletion of a population can not only harm [blank_start]other[blank_end] species in the ecosystem.

Water Use: There are changes occurring in [blank_start]rivers[blank_end] and [blank_start]watersheds[blank_end] due to humans. The majority of water that flows back into them is used for agriculture, industrial, and municipal.