Human Influences on Ecosystems

They capture energy from the sun

They break down dead matter and release nutrients back into the soil

They provide a source of food for the crops

They prevent weeds from growing

It decreases the need for land

It increases the pressure to convert natural habitats into farmland

It leads to a reduction in the use of fertilizers

It helps to restore the ozone layer

Ploughing straight up and down the hill

Terracing the slopes

Removing all trees and shrubs

Keeping the soil bare during the rainy season

Transpiration

Irrigation

Precipitation

Hydration

They might increase the growth rate of wild plants

They could transfer resistance genes to bacteria that cause human diseases

They will cause the animals to grow much slower than normal

They prevent the process of decomposition in the soil

Increasing the number of fishing boats in the fleet

Reducing the size of the holes in fishing nets

Implementing 'closed seasons' during the fish spawning period

Encouraging the capture of the youngest fish in the population

By increasing the number of people who can work on farms

By covering fertile arable land with buildings and roads

By reducing the demand for processed food products

By decreasing the concentration of carbon dioxide in cities

Food miles represent the distance food travels from producer to consumer; more miles generally result in higher $CO_{2}$ emissions from transport.

Food miles measure the number of acres required to produce one ton of a specific crop.

A high 'food miles' value indicates that the food is more nutritious because it has been grown in better soil far away.

The 'food miles' concept is used to calculate the amount of energy lost between the sun and the final consumer.

A massive loss of 'agrobiodiversity', leaving the global rice supply more vulnerable to future pests and diseases.

An increase in the total amount of nitrogen fixation globally as the new rice was more efficient at using bacteria.

A reduction in the global temperature as the new rice reflected more sunlight than the old varieties.

The evolution of new bird species that specialized in eating the new type of rice grain.

They require the largest home ranges to find enough food, and fragmented patches are often too small to support a viable population.

They are more sensitive to the change in $CO_{2}$ levels that occurs when forests are cleared.

The noise from agricultural machinery interferes with their ability to use echolocation for hunting.

They are the only organisms that cannot survive on the new crop species introduced by humans.

It is slower than it was 1000 years ago

It is occurring at a rapid pace due to human population growth

It has completely stopped in the last decade

It only happens in cold climates

The population size decreases, leaving a smaller gene pool

Animals mate with different species

Mutation rates decrease

The DNA of the animals changes instantly

Increasing the use of single-use plastics

Creating protected national parks

Expanding urban sprawl

Encouraging more monoculture

Top predators

Decomposers and detritivores

Large herbivores

Flying birds

The money governments must pay to protect endangered species.

The future extinction of species due to events that have already occurred.

The number of species that have already gone extinct in the past century.

The cost of restoring a habitat to its original state.

Scientists only look for medicines in urban areas.

Many plants with undiscovered medicinal properties go extinct before they can be studied.

Destroying habitats makes the remaining plants more toxic.

Synthetic medicines are always better than natural ones.

It increases soil aeration by creating deep ruts.

It causes soil compaction, which reduces the space for air and water.

It encourages the growth of deep-rooted plants.

It increases the population of earthworms by providing heat.

A reduction in the population of insectivorous birds and bats, leading to a massive increase in herbivorous insect pests.

The forest becomes too quiet, which prevents the remaining trees from growing due to a lack of 'vibrational stimulation'.

The dead wood would have otherwise turned into coal within a few years, providing a source of energy for the forest floor.

The lack of snags means that there is no 'lightning rod' for the forest, significantly increasing the risk of ground fires.

Increased competition for limited resources, leading to high mortality, reduced reproductive rates, and habitat degradation.

A rapid increase in the 'carrying capacity' of the fragment as the animals learn to share their resources more effectively.

The evolution of 'miniature' versions of the species that require fewer calories to survive in the smaller space.

A 'synergistic' effect where the high density of animals creates a 'microclimate' that protects the fragment from the edge effect.

Heterogeneity provides more niches; destruction usually simplifies the habitat, leading to a loss of specialized niches and species.

Heterogeneity is a measure of how many different species of 'Heterotrophs' are present; destruction increases this by bringing in new predators.

Destruction increases heterogeneity by creating a 'patchwork' of different land uses, which always increases species richness.

Heterogeneity refers to the size of the organisms; habitat destruction forces organisms to become smaller, increasing heterogeneity.

Increasing the use of pesticides

Reforestation and protecting natural habitats

Dumping more waste in landfills

Building more coal-fired power plants

High levels of oxygen

A mixture of smoke and fog combined with pollutants like nitrogen oxides

Too much water vapor from the ocean

The release of helium from balloons

Increased soil fertility

Thinning of eggshells in birds of prey due to biomagnification

Faster growth of aquatic plants

Reduction in atmospheric carbon dioxide

They increase the car's speed

They reduce the emission of toxic gases like carbon monoxide and nitrogen oxides

They help the car use more fuel

They prevent the car from making noise

Ploughing fields more deeply

Applying fertilisers in smaller amounts more frequently throughout the year

Removing all hedges and trees around the farm to increase airflow

Switching from sprinkler irrigation to flood irrigation

They reflect all sunlight, leading to global cooling

They can be inhaled deep into the lungs, causing respiratory and cardiovascular diseases

They react with nitrogen to form fertilisers in the air

They are the main cause of the depletion of the ozone layer

The use of heavy tractors that compress the soil

The anaerobic digestion of organic matter in the guts of livestock

The excessive application of nitrate-based fertilisers

The spraying of fungicides on fruit trees

Reduced $CO_2$ absorption by trees leads to increased sea temperatures and widespread coral bleaching.

Soil erosion increases the silt content of river runoff, which settles on reefs and blocks light for the coral's symbiotic algae.

Loss of the forest canopy increases surface wind speeds, creating large waves that physically fragment the reef structure.

The removal of forest roots reduces the biological filtering of nitrates from groundwater, leading to toxic red tides.

The high density of people breathing out warm air.

The absorption and re-radiation of heat by dark surfaces like asphalt and concrete.

The large number of parks and trees in cities.

The use of mirrors on the outside of tall skyscrapers.

DDT replaces the calcium in the eggshell with chlorine.

DDT interferes with the enzyme calcium-ATPase, which transports calcium to the shell gland.

DDT makes the bird too weak to sit on the eggs gently.

DDT causes the bird to produce too much acid, which dissolves the shell.

It increases the biodiversity of the area

It makes the crop more vulnerable to being wiped out by a single disease

It improves the quality of the soil over time

It encourages the growth of many different wild plants

They provide a source of firewood for everyone in the world

They protect coastlines from erosion and serve as fish nurseries

They are the best places to build large industrial ports

They prevent any rain from falling on coastal cities

They break down into soil nutrients very quickly

They persist in the environment and can harm wildlife for many years

They are the only source of food for many marine animals

They increase the rate of evaporation in the ocean

Using crop rotation and organic manures

Leaving the soil bare for many years

Applying excessive amounts of chemical fertilizers

Removing all vegetation from the land

The manufacture of computers in urban factories

Natural pollination of crops by wild insects

The extraction of oil from deep-sea wells

The production of electricity from nuclear power plants

The population of herbivores will decrease due to sadness

The population of herbivores will increase, potentially leading to overgrazing

The biodiversity of the ecosystem will increase as more space is available

The producers (plants) will grow much larger to fill the gap

The predators eat the pesticides directly because they taste like fruit

The toxins build up in the bodies of organisms at each trophic level (biomagnification)

The pesticides make the predators' skin too thick to move

The pesticides reduce the amount of sunlight reaching the predators' eyes

They can be used as a source of new genetic alleles for disease resistance or drought tolerance.

Wild relatives are always more delicious and will eventually replace commercial crops.

They produce more seeds per plant than domesticated varieties.

Wild relatives do not require any sunlight to grow.

Increasing the number of fishing boats every year to keep up with demand.

Using 'bottom trawling' to ensure all species are caught at once.

Implementing 'catch quotas' based on scientific estimates of the Maximum Sustainable Yield (MSY).

Feeding the wild fish population with processed corn to make them grow faster.

Invertebrates are eaten more quickly when the water is acidic.

The acidity prevents the formation of calcium carbonate shells or exoskeletons.

Invertebrates need higher levels of $SO_2$ to survive than fish.

Acid rain makes the water too clear, so invertebrates cannot hide.