B18 biology and ecosystems Flashcards
(47 cards)
Why is a population growth much better than other animals?
better health care so people are living longer
new medicines are being developed so people don’t die of previously fatal diseases
farmers are able to produce more food using new breeds and equipment
we have no predators
we can clear waste
What is a negative effect associated with population growth?
As the human population increases, the volume of waste and pollution that is produced also increases. Polluting an
ecosystem harms or kills the organisms that live within it.
Modern society is more consumable, which means humans manufacture more products and replace them more often. This consumption is not sustainable. Many natural materials, including fossil fuels, will soon run out and scientists argue that there is already too much waste.
Explain the three main types of pollution?
Water pollution
In some parts of the world, open sewers can lead into water courses, such as streams and rivers, which can cause serious illness in humans that may drink the contaminated water.
Some farmers use too many fertilisers, which can run off fields during heavy rain. This can pollute nearby streams and rivers leading to eutrophication. Some water pollution even comes from toxic chemicals released illegally by factories.
Air pollution
Combustion of fossil fuels and other fuels releases carbon dioxide. This contributes to the
greenhouse effect and leads to global warming. It also releases sulfur dioxide and nitrogen oxides which can cause acid rain. Air pollution can also be caused by tiny particulates from smoke which can cause smog. Some of the world’s major cities like Delhi in India and Karachi in Pakistan have dangerously high levels of air pollution.
Land pollution
The rubbish we throw out that is not
recycled goes into a land fill. These are huge holes in the ground into which our rubbish is dumped. Some things like batteries cannot be put into
landfill sites because of the toxic chemicals they contain. They must be recycled. Other land pollution comes when some people dump rubbish in public or other private places, often to avoid paying for it to be disposed of. This is called fly tipping and is illegal.
How does Land use affect the environment?
The larger the human population gets, the more land we require. More houses must be built, more resources found, more food must be grown and more waste is produced. This often means less space and fewer resources for other animals and plants.
Often biodiversity is significantly reduced when land is cleared for human uses, such as building, quarrying, farming and waste disposal. Think about the reduction in biodiversity, which occurs when an area of rainforest is cut down to grow crops.
How is consumerism not sustainable?
Modern society is more consumable, which means humans manufacture more products and replace them more often. This consumption is not
sustainable. Many natural materials, including fossil fuels, will soon run out and scientists argue that there is already too much waste.
What is deforestation and its effect?
Deforestation is the clearing of forests for other land uses, such as agriculture, urban development, or mining.
Deforestation has several significant effects:
Biodiversity Loss: Forests are home to a vast array of plant and animal species. Deforestation destroys habitats, leading to a decline in biodiversity and potentially extinction.
Climate Change: Trees absorb carbon dioxide from the atmosphere during photosynthesis. When forests are cleared, this stored carbon is released, contributing to greenhouse gas emissions and climate change. Deforestation also reduces the planet’s capacity to absorb future carbon emissions.
Soil Erosion: Tree roots help to hold soil in place. Deforestation leaves the soil exposed to wind and rain, leading to erosion. This can result in the loss of fertile land, sedimentation of waterways, and increased flooding.
Disruption of Water Cycles: Forests play a crucial role in regulating water cycles. They help to absorb rainfall, prevent runoff, and release water vapor into the atmosphere. Deforestation can disrupt these cycles, leading to decreased rainfall, increased drought, and altered river flows.
What are bogs and how significant is their destruction
Bogs are a type of wetland ecosystem characterised by acidic, waterlogged conditions and a build-up of partially decayed plant matter known as peat. They are typically nutrient-poor.
Human activities that lead to bog destruction include:
Peat Extraction: Peat is extracted for use as a fuel or for soil in horticulture.
Agriculture: Bogs are drained and converted into agricultural land.
The destruction of bogs is significant for several reasons:
Carbon Storage: Bogs are important carbon sinks, storing vast amounts of carbon in their peat. When bogs are destroyed, this stored carbon is released into the atmosphere as carbon dioxide and methane, contributing to climate change.
Biodiversity: Bogs provide a unique habitat for specialised plant and animal species, some of which are rare or endangered. Bog destruction leads to habitat loss and a decline in biodiversity.
.
What is the greenhouse effect?
The enhanced greenhouse effect refers to the increasing amount of greenhouse gases in Earth’s atmosphere as a result of human activities, primarily the burning of fossil fuels, deforestation, and industrial processes. This increase traps more heat and leads to a greater warming of the planet than would occur naturally.3
What is global warming and its impacts?
Global warming refers to the long-term increase in Earth’s average surface temperature due to the increase in greenhouse gases in the atmosphere.
What is conservation?
Keeping the environment healthy and productive by careful use of its resources.
How to maintain biodiversity?
Scientists and concerned members of the public help maintain biodiversity by:
breeding programs to help preserve
endangered species
, like the panda
protection and development of new endangered
habitats, often by making National Parks
replanting hedgerows because there is higher biodiversity in them than the fields they surround
reducing deforestation and the release of
greenhouse gases
recycling
rather than dumping waste in landfill sites
What factors affect food security?
Food security is a measure of the availability of food required to support people of a household, region, country or any specified area. It is a measure of how much food there is, if it is of suitable quality and whether people can access it.
Having fully stocked supermarket shelves is something that perhaps some of us might take for granted. However, this high level of food security is not experienced by all people. In some parts of the world there is a shortage of food, which can result in starvation and death. The United Nations estimate that around nine million people die of hunger each year.
Food security is reduced by:
the increase in human
population
, as birth rates are increasing and many people have better access to medical care
changing diets mean scarce food resources are transported to be sold to other areas from areas which need them
new pests and
pathogens
that attack crops and farm animals
The effects of climate change are making farming more difficult in many areas
increased costs of farming
armed conflicts
Finding
sustainable
ways to feed people is an important problem for scientists.
What are the two types of farming?
Intensive farming
Intensive farming
uses machines, natural and artificial fertilisers, and
high-yield
crops to maximise the amount of food produced. Most of the meat, fruit and vegetables, dairy products and eggs found in our supermarkets come from intensive farming so it is important for our food security. Farmers growing
arable
crops can specialise in growing only one crop to maximise the food they produce. This is called
monoculture
. This can reduce key nutrients in the soil and can lower
biodiversity
.
Hedgerows have been removed from many fields to make them bigger and easier to farm. This allows farmers to make more food. Often, more animals and plants live in hedgerows than fields and so their removal can also reduce biodiversity.
Some intensive farming can also mean keeping livestock in smaller pens with regulated temperatures. This reduces the energy they need for movement and temperature regulation and so maximises their size and yield. Some animals are fed high protein foods to increase their growth. They can also be fed antibiotics in their food to prevent diseases. Many scientists think this is a contributing factor to antibiotic resistance in bacteria.
Advantages and disadvantages of intensive farming practices: Advantages: higher yields, more efficient use of land
Disadvantages; antibiotic resistance and ethical objections.
Some people object to some modern intensive farming methods. Some farms have become
organic to address this. Organic farmers do not use machines to the same extent as intensive farming. They do not apply artificial pesticides to their crops and use natural fertilisers such as
compost and manure. They rotate their crops to avoid monoculture.
What are sustainable fisheries?
Sustainable
fisheries do not reduce the overall number of fish, because the number of fish that are caught and killed does not ever exceed the birth of new fish.
At one point we thought that we could remove as many fish as we wanted from the oceans without any consequence. During this period, we drastically
overfished
some of our oceans and seas and reduced some
populations
to critically low numbers.
Some scientists think that as much as 85% of the world’s fish populations have been overfished. Common examples are cod in the North Sea and sole in the Irish Sea and English Channel. Overfishing can cause a critical point in populations that means certain
species cannot ever recover and will become
extinct.
To address overfishing many countries are adopting a more sustainable strategy for fishing. These include Iceland and New Zealand. Many countries have introduced fishing quotas which limit the amount of fish that can be caught and killed from specific species. The size of the gaps in fishing nets has also been increased to ensure that juvenile fish can reach reproductive maturity and have offspring before being killed.
What are the three environmental changes
Seasonal Geographical and As a result of human action
What is meant by the term bioaccumulation?
an increase in the concentration of a chemical in a biological organism over time, compared to the chemical’s concentration in the environment.
Explain why it is important to dispose of sewage correctly?
toxic chemicals can spread from waste into soil,
toxic chemicals can be washed into waterways,
sewage can pollute soil with dangerous chemicals and gut parasites,
toxins build up in organisms along food chain (bioaccumulation),
largest predators die or are infertile due to toxic chemical build‑up
How does deforestation affect biodiversity?
Tropical rainforests contain more biodiversity than any other land
environment.
Loss of forests means biodiversity of plant and animal life is also lost
as habitats are destroyed and species become extinct.
Many species are being destroyed before being identified and studied,
so potential new sources of medicine or food could be lost.
Describe the pollution farming can have on Land and in Water
Land:
* pesticides and herbicides spread from crops into soil
* plant material contaminated with toxins
* small levels of toxins taken in by animals eating affected plant
material
* toxins build up along food chains (bioaccumulation) until toxic
levels are reached in top predators.
Water:
Fertilisers washed from the soil into streams, ponds, and rivers.
* Nitrates in fertilisers encourage the rapid growth of algae and
water plants.
* Microorganisms feeding on the plants use up oxygen decreasing
the levels of oxygen.
* Other oxygen-dependent organisms then die because of a lack
of oxygen.
How does deforestation contribute to global warming?
carbon dioxide produced by burning of trees,
carbon dioxide produced by decomposition of dead vegetation,
less carbon dioxide removed from atmosphere by growing plants
How is acid rain dangerous to the ecosystem?
Acid rain directly damages plant life by falling on plants
and by soaking into soil and being taken up by roots.
Acid rain contaminates soil and watercourses, making them more acidic and eventually unable to sustain life.
Increasing sulfur dioxide levels threaten to reduce global biodiversity
as whole ecosystems can be destroyed.
What are the biological consequences of global warming?
loss of habitat – reducing biodiversity
* changes in distribution – some organisms may disappear from
some areas as habitat changes
* changes in migration patterns – caused by changes in climates
and seasons
* reduced biodiversity – some organisms will become extinct as
climate changes
What is biomass?
The dry mass of an organism.
How do some organisms adapt to climate change?
Evolutionary Adaptation: Over generations, natural selection favours individuals with traits that help them survive and reproduce in the altered environment. This can lead to changes in the genetic makeup of populations.
Behavioural Changes: Some organisms alter their behaviour to cope with new conditions. For example, they might change their migration patterns, feeding habits, or breeding times.
Phenotypic Plasticity: This refers to the ability of an organism to change its physical or physiological traits in response to environmental changes, without any alteration to its genetic makeup.
