Skip to main content
Create interactive lessons using any digital content including wikis with our free sister product
. Get it on the
Pages and Files
Advanced Biology Anatomy and Physiology Projects
Basic Principles of Animal Form and Function
Circulation and Gas Exchange
Conservation Biology and Global Change
Ecology Home Page
Ecosystems and Restoration Ecology
Hormones and the Endocrine System
Introduction to Ecology
Nutrition and Digestion
Osmoregulation and Excretion
The Immune System
Add "All Pages"
Conservation Biology and Global Change
Conservation Biology and Global Change: Chapter 56
seeks to preserve life, it integreates: Ecology, Physiology, Molecular biology, Genetics, Evolutionary Biology
applies ecological principles to return degraded ecosystems to their natural state.
Humans threaten Earth's biodiversity
Over 1.8 million species have been named, but 10-200 million are estimated to exist and humans are pushing many towards extinction.
Levels of biodiversity:
Genetic Diversity - comprises genetic variation within and between populations
Species Diversity - the variety of species throughout the biosphere or within an ecosystem
are those "in danger of becoming extinct through out all or a significant portion of its rang."
are those likely to become endangered in the near future.
Conservation biologists are concerned with extinction since globally 12% of birds, 20% of mammals, and 32% of amphibians are threatened with extinction.
Ecosystem Diversity - variation of the biospheres ecosystems.
Reduced by human activity
Ex: <50% of wetlands have been drained and converted to other ecosystems
Humans should care about biodiversity because of
which is our sense of connection to nature and all life.
Benefits of Species and Genetic Diversity
Many threatened species could provide food, fibers, and medicine for human use.
25% of prescription are derived from plants
The loss of a species means losing genes. These genes could code for useful proteins that could be used in medicine, foods, and products.
encompass all the processes through which natural ecosystems and their species help sustain human life.
Air and water purification
Detoxification and decomposition of waste
Cycling of nutrients
Moderation of extreme weather
There are four major threats to biodiversity
Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere.
Brought about by: agriculture, urban development, forestry, mining, and pollution.
Habitat fragmentation and destruction leads to a loss of biodiversity.
IUCN implicates destruction of habitats for 73% of species extinctions.
98% of tropical dry forest in Mexio and Central America has been cut down
90% of tropical rain forest has been cut down
93% of coral reefs have been harmed
are those that humans move from native locations to new geographic regions.
Without predators, parasites, and pathogens the introduced species can rapidly spread.
Disrupt the new community
Can be introduced by accident if the plant seed or animal gets onto a ship/plane and gets carried to another place.
Can be introduced on purpose with good intentions and then have bad effects.
Overexploitation is human harvesting of wild plants/animals at rates exceeding the ability of those species populations to rebound.
In the fishing industry many game fish populations have been greatly reduced.
DNA can help conservation biologists identify the source of illegally obtained animal products.
Global change is alterations in the fabric of Earth's ecosystems at regional to global scales.
Changes in the atmosphere chemistry, climate, etc
Population conservation focuses on population size, genetic diversity, and critical habitat
Follow two main approaches:
Small-population approach: studies processes that can make small populations become extinct.
Small populations are vulnerable to inbreeding and genetic drift which draws the population down an
to smaller and smaller population size until there are no surviving individuals.
The Greater Prairie Chicken and the Extinction Vortex case study showed that the declining population rebounded, confirming that it had been on its way to extinction due to low genetic variation but the transfusion of genetic variation saved them.
Minimum viable population (MVP)
is the minimum population size at which a species can survive.
Depends on factors that affect a population's chances for survival over time.
Effective population size
is based on the population's breeding potential and helps determine a meaningful estimate of MVP.
Effective size = 4(number males x number females)/(number males + number females)
First tests of this was on grizzly bears
Focuses on threatened and endangered populations that show a downward trend.
Emphasizes the environmental factors that caused a population to decline.
Steps for Analysis and Intervention
Confirm that population is in decline
Study species natural history
Develop hypotheses of all possible causes of decline
Test the hypothesis in order of likeliness
Apply results to manage the species and monitor its recovery
Weighing Conflicting Demands
Species conversations requires resolving conflicts between habitat needs and human demands.
Managing habitat for one species may have an affect (positive or negative) on other species.
Landscape and regional conservation help sustain biodiversity
Seeks to make biodiversity conservation a part of land-use planning.
Landscape structure can influence biodiversity.
Fragmentation and Edges
Edges (boundaries) between ecosystems are defining features of landscapes.
Certain species take advantage of edge communities to access resources from both adjacent areas.
The Biological Dynamics of Forest Fragments Project found that landscapes dominated by fragmented habitats support fewer species due to a loss of species adapted to habitat interiors.
Corridors that connect habitat fragments
is a narrow strip of quality habitat connecting otherwise isolated patches.
Promote dispersal and help sustain populations
Sometimes are human constructed
Establishing Protected Areas
Apply understanding of ecological dynamics to protect areas and slow the loss of biodiversity. Focus on hot spots of diversity.
biodiversity hot spot
is a small area with a great concentration of endemic species and endangered and threatened species.
Good choices for nature reserves.
Nature reserves are biodiversity island in a sea of habitat degraded by human activity.
Must consider disturbances as a functional component of all ecosystems.
Large reserves may be better since large, far-ranging animals with low-density populations require extensive habitats.
Small reserves are more realists and may slow the spread of disease throughout a population.
is a extensive region that includes areas relatively undisturbed by humans surrounded by areas that have been changed by human activity.
Used for economic gain
Known as conservation areas
Earth is changing rapidly as a result of human actions
Humans transport and add new materials (including toxins) to ecosystems.
Agriculture leads to the depletion of nutrients in the soil.
Fertilizers add nitrogen to the ecosystem.
is the amount of added nutrient that can be absorbed by plants without damaging the integrity of the ecosystem.
Runoff and sewage from agriculture leads to phytoplankton blooms in the Atlantic Ocean. When these blooms decompose "dead zones" occur due to low oxygen levels.
Toxins in the Environment
Humans release toxic chemicals that were previously unknown by nature.
Harmful substances can last for long periods of time in an ecosystem.
concentrates toxins at higher trophic levels where biomass is lower.
PCBs and pesticides are subject to biological magnification
Ex: herring gulls of the Great Lakes lay eggs with PCB levels 5,00 time greater than in phytoplankton.
Greenhouse Gases and Global Warming
Burning fossil fuels and things such as deforestation cause carbon dioxide levels in the atmosphere to increase.
is when carbon dioxide, water vapor, and other greenhouse gases reflect infrared radiation back towards Earth.
Affects Earth's surface temperature
Affects distribution of precipitation
Global warming can be slowed by reducing energy needs and converting to renewable sources of energy.
Will take an international effort
Depletion of Atmospheric Ozone
A layer of ozone molecules in the atmosphere protects Earth from the damaging effects of UV radiation.
Satellite studies showed that ozone has been thinning since the 1970s.
Ozone destruction is mainly a result of chlorofluorocarbons (CFCs) produced by humans.
CFCs contain chlorine which react with ozone and makes oxygen, this is what causes ozone to thin.
Ozone depletion causes DNA damage to plants and poor phytoplankton growth. In humans in can cause skin caner.
Sustainable development can improve human lives while conserving biodiversity
Helps to establish long-term conservation priorities.
Sustainable Biosphere Initiative
is development that meets the needs of people without limiting the ability of future generations to meet their needs.
Sustainable Biosphere Initiative: goal is to define and acquire basic ecological information for responsible development, management, and conservation of Earth's resources.
Connects life sciences, social sciences, economics, and humanities.
The Future of the Biosphere
Modern lives differ from lives of early humans. Our behaviors reflects remnants of our ancestral attachment to nature and the diversity of life - concept of
The sense of connection to nature could motivate realignment of environmental priorities. By understanding the processes and diversity of life, we become more aware of ourselves and our place in the biosphere.
Click here to return to Ecology home page
help on how to format text
Turn off "Getting Started"