1.
Define biodiversity, sustainability, habitat, biotic ecosystem and abiotic
ecosystem
Biodiversity refers to the variety and variability of life on Earth. Biodiversity is
typically a measure of variation at the genetic, species, and ecosystem level.
Terrestrial biodiversity is usually greater near the equator, which is the result
of the warm climate and high primary productivity.
Sustainability is the process of maintaining change in a balanced
environment, in which the exploitation of resources, the direction of
investments, the orientation of technological development and institutional
change are all in harmony and enhance both current and future potential to
meet human needs and aspirations.
Habitat the area or natural environment in which an organism or population
normally lives. A habitat is made up of physical factors such as soil, moisture,
range of temperature, and availability of light as well as biotic factors such as
the availability of food and the presence of predators.
Biotic components are the living things that shape an ecosystem. Examples
of biotic components include animals, plants, fungi, and bacteria.
Abiotic components are non-living components that influence an ecosystem.
Examples of abiotic factors are temperature, air currents, and minerals
2. Describe changes in biodiversity
The link between climate change and biodiversity has long been established.
Although throughout Earth's history the climate has always changed with
ecosystems and species coming and going, rapid climate change affects
ecosystems and species ability to adapt and so biodiversity loss increases.
Healthy ecosystems and rich biodiversity are fundamental to life on our planet.
Climate change is affecting the habitats of several species, which must either
adapt or migrate to areas with more favourable conditions. Even small
changes in average temperatures can have a significant effect upon
ecosystems.
3. Describe each of the following threats of Biodiversity as to:
a. Habitat loss and destruction
Habitat loss and destruction Natural habitats are the physical, chemical
and biological systems that support living things (i.e. plants, animals, fungi
and microbes). More simply put, habitats are the places where these
organisms live. Habitat is lost and degraded when natural or
human-caused activities alter these places so that fewer species can live
there. For example, when a section of forest is cut down and replaced
with farmland or urban spaces, the living places of hundreds of species
may be eliminated. Habitat loss is not only a concern from the point of
view of compassion for other species that share this planet. Humans are
part of the great cycle of life on earth, and as such we depend on the
overall function of natural systems for our own survival. Properly
functioning natural systems create the air we breathe, break down our
wastes, provide our food, purify our drinking water and ultimately supply
all the materials we require for living. Each species plays an important
role in its ecosystem. Habitat loss and degradation is the main threat to
the world's endangered plants and animals, and is occurring at ever
greater rates.
b. Alterations in ecosystem composition
c. Over-expoitation
Overhunting, overfishing and over-harvesting contribute greatly to the
loss of biodiversity, killing off numerous species over the past several
hundred years. Poaching and other forms of hunting for profit increase the
risk of extinction; the extinction of an apex predator — or, a predator at
the top of a food chain — can result in catastrophic consequences for
ecosystems.
d. Pollution and contamination
From the burning of fossil fuels (releasing dangerous chemicals into the
atmosphere and, in some cases, depleting ozone levels) to dumping 19
billion pounds of plastic into the ocean every year, pollution completely
disrupts the Earth's ecosystems. While it may not necessarily cause
extinction, pollutants do have the potential to influents species' habits. For
example, acid rain, which is typically caused by the burning of fossil fuels,
can acidify smaller bodies of water and soil, negatively affecting the
species that live there by changing breeding and feeding habits.
e. Global climate change
Climate change is one of the biggest threats to biodiversity on a long-term
scale. Carbon emissions caused by human activity are causing
temperature changes that affect ecosystems and so impact upon animal
and plant species. It is causing some animal populations to migrate to
areas they would not normally inhabit, with the potential to upset those
systems, while also directly causing numbers to decline. Climate change
is also causing more unpredictable extreme weather events, such as
tsunamis and droughts, which affect biodiversity and the ability of
ecosystems to regenerate. It is also affecting where humans are able to
grow crops, which will also have an impact on native plants and animals,
with the attendant problems due to habitat.
4. Consequences of biodiversity loss
The loss of biodiversity has many consequences that we understand, and
many that we do not. It is apparent that mankind is willing to sustain a great
deal of biodiversity loss if there are concomitant benefits to society; we hope
they are net benefits. In many cases, the benefits seem to accrue to a few
individuals only, with net societal loss. However, as noted below, it is
extremely difficult to estimate the future costs of losses in biodiversity, or of
environmental damage. Losses in biodiversity in rainforests cause significant
changes in ecosystem functioning. About ecosystem functioning in tropical
rain forests we know very little, but we do know that ecosystems are affected
by changes in the number and kinds of species which they contain, an idea
originally conceived by Charles Darwin and Alfred Russel Wallace. Intact
ecosystems function best, since the organisms composing them are
specialized to function in that ecosystem to capture, transfer, utilize and,
ultimately, lose both energy and nutrients. The particular species making up
an ecosystem determine its productivity, they affect nutrient cycles and soil
contents, and they influence environmental conditions such as water cycles,
weather patterns, climate and other no-biotic aspects.
a. Species richness: For example, in some, but not all, experimental systems,
increasing plant diversity alone, or increasing the diversity of plants,
herbivores, and decomposing organisms augments productivity (NPP). It has
generally been found, at least in temperate grasslands, that areas with
greater biodiversity have higher productivity. Plots with greater numbers of
species had a greater above- and below-ground plant biomass, higher rates
of nitrogen fixation, and retained nutrients better than plots with fewer
species.
b. Species composition: The array of species in an ecosystem (species
composition) must also be important to its function. Certain species will have
a greater influence than others, particularly if they are among those groups
which capture and transfer energy or nutrients, or which affect environmental
conditions regulating these processes.
c. Species interactions: Species interactions are perhaps the most important
aspect of ecosystem functioning. Species are not just “there,” they are
interacting at some level with all the other organisms in the system, forming
highly complex interlocking systems. They compete, they parasitize, they
cooperate, they prey, they provide food or shelter.
d. Ecosystem stability: The”diversity-stability hypothesis”: The idea behind this
hypothesis is that biodiversity acts as a stabilizing factor in ecosystems, and
that therefore highly diverse ecosystems can act to reduce the impact of
changes in the environment. Since humans are now altering so many
environmental variables – atmospheric gases, surface temperatures, water
quality – it behooves us to maintain as many areas with high biodiversity as
possible.
5. Nutritional impact of biodiversity
Biodiversity plays a crucial role in human nutrition through its influence on
world food production, as it ensures the sustainable productivity of soils and
provides the genetic resources for all crops, livestock, and marine species
harvested for food. Access to a sufficiency of a nutritious variety of food is a
fundamental determinant of health. Nutrition and biodiversity are linked at
many levels: the ecosystem, with food production as an ecosystem service;
the species in the ecosystem and the genetic diversity within species.
Nutritional composition between foods and among varieties/cultivars/breeds
of the same food can differ dramatically, affecting micronutrient availability in
the diet. Healthy local diets, with adequate average levels of nutrients intake,
necessitates maintenance of high biodiversity levels. Intensified and
enhanced food production through irrigation, use of fertilizer, plant protection
(pesticides) or the introduction of crop varieties and cropping patterns affect
biodiversity, and thus impact global nutritional status and human health.
Habitat simplification, species loss and species succession often enhance
communities vulnerabilities as a function of environmental receptivity to ill
health.
