This document discusses biodiversity at three levels - species diversity, genetic diversity, and ecosystem diversity. It notes that species diversity is highest near the equator and in coastal areas with warm sea surface temperatures. Throughout history there have been several mass extinction events that dramatically reduced biodiversity. Currently, the Holocene extinction caused by human activity is reducing biodiversity. The document outlines that each level of biodiversity influences the others, and loss at one level can impact the other levels. Maintaining biodiversity is important for sustaining ecosystem productivity and resilience against disasters.
Human well-being is highly dependent on ecosystems and the benefits they provide such as food and drinkable water. Over the past 50 years, however, humans have had a tremendous impact on their environment.
To better understand the consequences of current changes to ecosystems and to evaluate scenarios for the future, UN Secretary General Kofi Annan has launched a comprehensive scientific study, the Millennium Ecosystem Assessment.
What actions could be taken to limit harmful consequences of ecosystem degradation?
A community is a complex group of individuals interacting and sharing an environment.
Communities can be characterized by their structure (the types and numbers of species present) and dynamics (how communities change over time).
Human well-being is highly dependent on ecosystems and the benefits they provide such as food and drinkable water. Over the past 50 years, however, humans have had a tremendous impact on their environment.
To better understand the consequences of current changes to ecosystems and to evaluate scenarios for the future, UN Secretary General Kofi Annan has launched a comprehensive scientific study, the Millennium Ecosystem Assessment.
What actions could be taken to limit harmful consequences of ecosystem degradation?
A community is a complex group of individuals interacting and sharing an environment.
Communities can be characterized by their structure (the types and numbers of species present) and dynamics (how communities change over time).
Keynote address for the Fair Housing Center of Southeastern Michigan's 2nd Annual Fair Housing Breakfast Event on March 25, 2015, in Ann Arbor MI. Slideshare of the presentation given by Jason Reece, Director of Research for the Kirwan Institute for the Study of Race & Ethnicity. www.fhcmichigan.org
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Environmental Science Table of Contents 37 L.docxYASHU40
Environmental Science Table of Contents
37
Lab 3
Biodiversity
Biodiversity
Concepts to Explore
• Biodiversity
• Species diversity
• Ecosystem diversity
• Genetic diversity
• Natural selection
• Extinction
Introduction
Biodiversity, short for biological diversity, includes the genetic variation between all organisms, species, and
populations, and all of their complex communities and ecosystems. It also reflects to the interrelatedness of
genes, species, and ecosystems and their interactions with the environment. Biodiversity is not evenly distrib-
uted across the globe; rather, it varies greatly and even varies within regions. It is partially ruled by climate,
whereas tropical regions can support more species than a polar climate. In whole, biodiversity represents
variation within three levels:
• Species diversity
• Ecosystem diversity
• Genetic diversity
It should be noted that diversity at one of these levels may
not correspond with diversity within other levels. The degree
of biodiversity, and thus the health of an ecosystem, is im-
pacted when any part of that ecosystem becomes endan-
gered or extinct.
The term species refers to a group of similar organisms that
reproduce among themselves. Species diversity refers to
the variation within and between populations of species, as
well as between different species. Sexual reproduction criti-
cally contributes to the variation within species. For exam-
ple, a pea plant that is cross-fertilized with another pea plant
can produce offspring with four different looks! This genetic
mixing creates the diversity seen today.
Figure 1: There are more than 32,000 species of
fish – more than any other vertebrate!
39
Biodiversity
Ecosystem diversity examines the different habitats, biological communities, and ecological processes in
the biosphere, as well as variation within an individual ecosystem. The differences in rainforests and deserts
represent the variation between ecosystems. The physical characteristics that determine ecosystem diversity
are complex, and include biotic and abiotic factors.
? Did You Know...
A present day example of natural
selection can be seen in the cray-
fish population. The British crayfish
are crustaceans that live in rivers in
England. The American crayfish
was introduced to the same bodies
of water that were already populat-
ed by the British crayfish. The
American crayfish are larger, more
aggressive and carry an infection
that kills British crayfish but to
which they are immune. As a re-
sult, the British crayfish are de-
creasing in number and are ex-
pected to become extinct in Britain
within the next 50 years. Thus, the
American crayfish have a genetic
variation that gives them an ad-
vantage over the British crayfish to
survive and reproduce.
The variation of genes within individual ...
Answer (6)THREE WAYS HUMAN HAVE NEGATIVELY IMPACTED BIODIVERSITY .pdfangelsfashion1
Answer (6)
THREE WAYS HUMAN HAVE NEGATIVELY IMPACTED BIODIVERSITY :-
(A) Population:-
Growth of the human population is a major factor affecting the environment. Simply put,
overpopulation means that there are more people than there are resources to meet their needs.
Almost all the environmental problems we face today can be traced back to the increase in
population in the world. The human population is at 6 billion; with an annual global growth rate
of 1.8%, three more people are added to the earth every second.
(B) Habitat Removal and Alteration :-
Habitat fragmentation is the loss and subdivision of a habitat and the corresponding increase in
other habitats in the landscape. Conversion of habitat represents the greatest threat to
biodiversity, since almost all human activities cause alterations to the natural environment to a
greater or lesser degree. Almost 10% of Canada\'s ecoregions are estimated to be at high risk for
loss of biodiversity because of habitat removal.
(C) Overharvesting/Overexploitation :-
Overharvesting has had the greatest effect on biodiversity. In fact, overharvesting and habitat
loss often occur simultaneously, as removal of an organism from its environment can have
irreversible impacts on the environment itself.
Humans have historically exploited plant and animal species in order to maximize short-term
profit, at the expense of sustainability of the species or population. This exploitation follows a
predictable pattern: initially, a species harvested from the wild can turn a substantial profit,
encouraging more people to get involved in its extraction. This increased competition encourages
the development of more large-scale and efficient methods of extraction, which inevitably
deplete the resource.
(D) Pollution :-
Toxic discharges: This includes metals, organic chemicals, and suspended sediments usually
found in industrial and municipal effluents that are discharged directly into waterbodies. Toxic
discharges can inversely impact the biota (living organisms) in an ecosystem by killing them,
weakening them, or affecting their ability to carry out essential biological functions (feeding,
reproducing, etc.).
bacterial contamination: For example, fecal coliforms that come from human waste are found in
municipal effluent discharges. Potable water is treated to destroy fecal coliforms which can make
people ill if ingested.
nutrient buildup: Most concern are phosphorus and nitrogen which often originate as run-off
from fertilizers applied on agricultural fields. These nutrients, naturally present in very low
concentrations, stimulate rapid growth of algae and aquatic plants, ultimately limiting the amount
of oxygen and light available to other organisms in the ecosystem. As well, aquatic environments
can be degraded by habitat alteration and presence of invasive species.
Answer (7);
SPECIES DIVERSITY
This refers to the variety of species within a particular region. The number of species in a region
is a measure for such.
1. Biodiversity
Biodiversity is the degree of variation of life forms within a given species, ecosystem, biome, or
planet. Terrestrial biodiversity tends to be highest at low latitudes near the equator,[1]
which
seems to be the result of the warm climate and high primary productivity.[2]
Marine biodiversity
tends to be highest along coasts in the Western Pacific, where sea surface temperature is highest
and in mid-latitudinal band in all oceans.[3]
Biodiversity generally tends to cluster in hotspots,[4]
and has been increasing through time[5][6]
but will likely slow in the future.[7]
Rapid environmental changes typically cause mass extinctions.[8][9][10]
One estimate is that <1%-
3% of the species that have existed on Earth are extant.[11]
Since life began on Earth, five major mass extinctions and several minor events have led to large
and sudden drops in biodiversity. The Phanerozoic eon (the last 540 million years) marked a
rapid growth in biodiversity via the Cambrian explosion—a period during which the majority of
multicellular phyla first appeared.[12]
The next 400 million years included repeated, massive
biodiversity losses classified as mass extinction events. In the Carboniferous, rainforest collapse
led to a great loss of plant and animal life.[13]
The Permian–Triassic extinction event, 251 million
years ago, was the worst; vertebrate recovery took 30 million years.[14]
The most recent, the
Cretaceous–Paleogene extinction event, occurred 65 million years ago and has often attracted
more attention than others because it resulted in the extinction of the dinosaurs.[15]
The period since the emergence of humans has displayed an ongoing biodiversity reduction and
an accompanying loss of genetic diversity. Named the Holocene extinction, the reduction is
caused primarily by human impacts, particularly habitat destruction. Conversely, biodiversity
impacts human health in a number of ways, both positively and negatively.[16]
Levels of Biodiversity
Scientists speak of three levels of biodiversity: a. Species diversity b. Genetic diversity
c. Ecosystem diversity.
In effect, these levels cannot be separated. Each is important, interacting with and influencing the
others. A change at one level can cause changes at the other levels
Species Diversity
In all shape and size (tiny organisms to huge one): includes bacteria, protozoan, fungi, flowering
plants, ants, beetles, butterflies, birds, reptiles and large animals.
Each species is a group of organisms with unique characteristics. An individual of a species can
reproduce successfully, creating a viable offspring, only with another member of the same
species. Still learning how many species exist and how they relate to each other and to their
2. physical environment. Cannot predict the precise ripple effects that the loss of one species will
have on others and on ecosystems.
Keystone species: Plays critical role in ecosystems they inhabit Affect the abundance and health
of many other species. Their loss from ecosystems directly endangers the success of other
species. Scientists estimate between 10 to 30 million species on Earth. Only about 1.75 million
have been named and catalogued.
Most of insects, fungi and microscopic creatures remain unidentified. Their existence is a
mystery.
Genetic Diversity
Every individual inherits genes from its parents and passes on to the next generation.
Biodiversity is more than the variety of species. Genetic diversity everywhere (songs, feather
colors, taste and texture). Genetic variation is extremely important to the survival of species.
Genetic variability, responsible for these different traits, interact with local environmental
conditions to determine the extent to which populations can adapt to environmental changes and
survive exposure to new diseases.
Isolated populations in small patches of habitat cut off from the surrounding environment tend to
have less genetic variation than populations in large, intact ecosystems. Therefore, those isolated
populations are more susceptible to extinction.
Ecosystem Diversity
Populations and non-living environmental components- such as water or minerals surrounding
them interact dynamically to form an ecosystem. It includes: predators consuming prey,
pollinators selecting flowers and species responding to physical processes such as heavy rain.
Plant and Animal communities make up many kinds of ecosystems (forest, wetlands, rangelands,
mountains, deserts, terrestrial ecosystems). Species are not evenly distributed.
Why is Biodiversity Important?
Biodiversity boosts ecosystem productivity where each species, no matter how small, all have
an important role to play.
For example,
A larger number of plant species means a greater variety of crops
Greater species diversity ensures natural sustainability for all life forms
Healthy ecosystems can better withstand and recover from a variety of disasters.
And so, while we dominate this planet, we still need to preserve the diversity in wildlife.