Bell-ringer: What do you think biodiversity encompasses ...
Transcript of Bell-ringer: What do you think biodiversity encompasses ...
Bell-ringer: What do you think biodiversity encompasses?
Period 3 retake quiz
Biodiversity notes
Biosphere 2 video clip
Wrap-up: What was the point of the biosphere 2 experiment?
In July 1991 eight “Biospherians” started a daring biodiversity experiment that called for the eight people to live in the airtight Biosphere 2 for two years.
Had a footprint of 13,000 square meters and enclosed 204,000 meters cubed
Housed simplified versions of a desert, savanna, tropical forest, wetland, and a small ocean
Hoped that the plants, animals, and other organisms in these simplified biomes would generate their air, food, and water
Spectacular failure
By January 1993 the O2 content dropped from 19% to 14% (close to minimum needed for humans)
CO2 concentration rose
Before the 2 year mark, O2 was added to prolong the experiment
After 3 years the atmospheric conc. of N2O reached 79 ppm (310 ppm in Earth’s atm)
Low levels reduce the production of vitamin B12 and can damage the human brain
Nonhuman populations also changed
Morning glory vines, added to reduce CO2, overran other plants despite weeding efforts
Water system became overloaded with nutrients and polluted the aquatic system
All pollinators died flowering plants could not produce food for the Biospherians
19 out of the 25 vertebrates species went extinct, as did most of the insects other than cockroaches
Cost about $200 million to build, and several million to operate/year
Failed for reasons that reflect the technical and scientific shortcomings of both the Biospherians and the wider ecological community.
Rise in CO2 was caused in part by microbial degradation of organic carbon in the soils
Human food production requires soils with high organic content
Biospherians must have forgot that respiration reduces oxygen levels
O2 levels reduced when CO2 combined with Ca in cement locking up original O2 in cement walls
Bell-ringer: Why did the biosphere 2 fail?
Notes
Biosphere video clip
Wrap-up: What is species richness?
Not possible to build a simplified ecosystem that can supply and recycle the food, water, and gases that people need
Illustrates the danger of losing biodiversity
Driving a wave of mass extinctions with little understanding of the implications for biogeochemical cycles, food webs, diversity, resistance, or resilience
Refers to the number and variety of living organisms
Umbrella term that encompasses all plants, animals, microorganisms, and ecosystems
Measured at three levels: Genetic diversity
Ecosystem Diversity
Species Diversity
Refers to the genetic information in the DNA of plants, animals, and microorganisms.
Genetic diversity is the raw material for natural selection, which plays an important role in evolution.
Describes the variety of ecosystems on Earth such as coral reefs, forests, and wetlands.
Also involves variation within ecosystems regarding the number and types of organisms, habitats, and ecological processes such as nutrient cycling.
Refers to the total number of living species
Currently biologists have identified about 1.7 million species, the majority of which are insects
New species are identified at the rate of about 300 per day
It is estimated that 10 million to 100 million species exist, but no one is quite sure.
One way to measure species diversity
Refers to the number of species present
An area with an especially large number of species is called a biodiversity hot spot
The second way to measure species diversity
Refers to the distribution of individuals among species and measures whether individuals are distributed evenly among species or represent a few of the many species present
Evenness decreases as the concentration of individuals in a few species increases
Costa Rican rain forest area of 14 km2
Has about 1500 plant species which is more than all of Great Britain ( 243,500 km2 )
In general, species richness is greatest near the equator and declines toward the poles
Observation: Species richness is greatest near the equator and declines toward the poles
Support: Species richness depends on the balance between the gain in new species and the loss of existing species
Areas gain species via speciation and immigration and loose species via extinction
Speciation: the process by which evolution generates new species
Immigration: occurs when new species spread into an area from elsewhere
Study done by Robert MacArthur and Edward O. Wilson
Found that the number of lizard species on Caribbean islands varies positively with the area of the island
**Species richness increases with island size**
Larger islands such as Cuba (100, 860 km2) have more lizard species than smaller islands such as Saba (13 km2)
This applies to not just lizards but also other animals, birds, and plants
Also applies to other environments like lakes and mountaintops
Tend to have fewer species Can be explained by immigration
Few new species arrive at islands that are far from the mainland or other islands because organisms or seeds must travel a long distance
The ability of organisms to reach new environments
Def: The distance a species can travel to find new environments
Lizards are not good swimmers – must hitch a ride on floating materials
Birds can fly – some over great distances
Light seeds can be blown over long distances, other seeds can float (coconuts)
A species that is restricted to a certain geographic region and is thought to have originated there
Relatively little ability to disperse and often found in a single place
1.) Allopatric speciation Occurs when a population becomes geographically
isolated from its parent population then accumulates genetic or behavioral changes that differentiate from the original population
2.) Sympatric speciation New species may arise within the parent population
Scenario 1: A few individuals may find their way to a new island
Scenario 2: A large population may be separated into smaller subpopulations by the formation of a new mountain, land bridge, or some other barrier
Both processes isolate the subpopulation which makes it different than parent population
Difference from the parent population that accumulate due to isolation may be driven by random changes in the gene pool
These random changes are known as genetic or random drift
Changes may also be from natural selection which favors traits different than those favored in the original location
Rose from the ocean about 3 million years ago
May have accelerated allopatric speciation of snapping shrimp
Before the land bridge the shrimp where found in both the western Caribbean and the eastern Pacific
After the land bridge they changed genetically and behaviorally on each side
If male and female shrimp from either side of the land bridge are put in the same tank they do NOT BREED
They snap at each other
The inability to produce offspring makes them TWO DIFFERENT SPECIES
New species arise within the parent population
May be powered by mutations that occur during cell division
Different species could also interbreed to from a new species
Modern wheat plant Produces the flour for our bread
Offspring of earlier wheat plants and a wild grass
Home to nearly 200 species of cichlid fish
Less than 1 million years old leads scientists for hypothesize that the rapid speciation was driven by exploitation of new food resources and habitats
Important for ecosystem function
Makes important contributions to human well-being as a source of insurance, genetic knowledge, and ecosystem services
Argues that nonhuman species have value in and of themselves and have the right to exist independent of their usefulness to humans.
Human-centered perspective on the relationship between humans and other species hold that other species exist for human use, and their importance is determined by their value to humans.
Based on ethical beliefs – cannot be reconciled by science
Ex.) In 1999 there was ethical debate about destroying the last known sample of the smallpox virus
Could the extinction of the smallpox virus be justified on the basis of reducing human suffering?
Southeastern portion of the US
Digs burrows that can reach 2 meters below the surface
Depth were microclimate remains relatively constant year-round
These burrows not only protect the tortoise but also many other species (indigo snake & burrowing owl)
Species whose presence and numbers control the integrity of a community or ecosystem and allow that system to persist within its nature range of environmental conditions
Ex.) Gopher Tortoise
Experiment where scientists added phosphorus and nitrogen fertilizers to two lakes
Adding fertilizer retained top-level predators such as largemouth bass and increased NPP, which allowed the lake to remove carbon from the atmosphere
Added same amount of fertilizer but removed all top-level predators including largemouth
Bass feed on smaller fish such as fathead minnows
Fathead minnows and other small fish eat zooplankton, which allowed the fertilizer to increase the algae population
The algal bloom caused the lake to become eutrophic, which cause it to emit CO2
Largemouth are a KEYSTONE SPECIES!!!
Insurance: spreads the potential effects of risk When you buy insurance, you sign a contract that
entitles you to compensation should some event happen
To maintain insurance you make payments that are called an insurance premium
You pay the premium w/o knowing whether or not the event that triggers compensation will occur
Society bought insurance by supporting the International Rice Research Institute
Used funds from international organizations such as the Food and Agriculture Organization of the UN and the World Bank to preserve seeds from rice varieties that were considered uneconomic.
Applies to varieties that produce lower yields than varieties currently grown by famers
There was no immediate economic reason to preserve the seeds of uneconomic varieties
Potential value lay in the future, when some unknown aspect of their genetic diversity could be of economic value
Some varieties’ resistance to the grassy stunt virus, which first appeared in the 1970s
Virus threatened much of the Asian rice harvest
In some years, the virus eliminated nearly a quarter of the potential yield
IRRI launched a breeding program by growing rice from uneconomic seeds it had preserved
Hoped that one variety had a genetic component that would allow it to resist the grassy stunt virus
After several years they identified a resistant variety
Variety would have been extinct if IRRI hadn’t saved the seeds!
Allows farmers to practice agricultural techniques that are highly productive but would be too risky w/o insurance
Modern farmers plant a few highly productive varieties of corn, wheat, or rice over large areas generates large amounts of money and food
Risk: Genetically identical food source that could be wiped out by the same disease!
September 1845 leaves on potato plants turned black and curled, then rotted
Cause was an airborne fungus (phytophthora infestans) transported from ships travelling from N. America to England
Winds from southern England carried the fungus to Dublin
A single infected plant could infect thousands more in just a few days
Potatoes dug out of the ground at first looked edible but shriveled and rotted within days
By October 1845, news of the blight reached London
Prime Minister sent scientists to determine the outlook over half of Ireland’s potato crop might perish due to “wet rot”
Static electricity from newly arrived locomotive trains
Mortiferous vapors from volcanoes emanating from the center of the earth
Divine punishment for the “sins of the people”
Judgment against abusive landlords and middlement
Prime Minister repealed England’s long-standing Corn Law (made corn really expensive to foreign countries)
English gentry and politicians raised a fuss and would not allow it to happen with fear of losing their fortune
Prime Minister secretly purchased two shipments of inexpensive Indian corn directly from America to be distributed to Irish
Needed to be digestible corn meal so it had to be ground and there were not enough mills in a nation of potato farmers
Irish found corn unsuitable when compared to potatoes lacked vitamin C (led to scurvy) and was hard to digest causing diarrhea
Single greatest threat to biodiversity
Large-scale alteration of natural ecosystems by humans
Examples: Deforestation and reforestation
Urbanization
Desertification and conversion to agriculture Wetland drainage, irrigation and degradation due to
overgrazing
The change of land quality
In the last 3 centuries it has eliminated nearly 20% of earth’s forests, altered 8% of earth’s grassland, and expanded croplands by nearly 500%
Reduces biodiversity by eliminating habitats in a given biome
The breakup of a continuous habitat, ecosystem, or land use type into smaller areas
Breaking up forest into smaller fragments generates longer edges, which create transition zones between different land covers
Can help species diversity by creating areas that support species that cannot exist in either of the adjacent land covers
Yet in many cases it disrupts ecosystem process
Expose forest species to unfavorable conditions such as:
Stronger winds
Temperature changes
Increased incidence of fire
Increased predation & competition from exotic species and pests
Edges increase the damage and death rates of trees living in the Amazon forest – up to 500m from an edge
Only 39% of the loss of habitat from 1978-1988 was caused by forest clearing, the rest occurred through fragmentation and edge effects
Plants and animals often come along with people who travel
Ex.) Polynesians brought rats to Easter Island
No terrestrial vertebrates were present before humans arrived
When they displace indigenous species or spread into habitats where they were not previously common
79 alien species caused $97 billion in damages between 1901 and 1991
Currently is set to be $138 billion a year
Ex.) Zebra mussels $5 billion per year
The original habitat of a species, where they evolve with other species
A variety of predatory, parasitic, and disease organisms often keep the populations in check
The new environment that a species is introduced into
Previously limiting factors are no longer in place allowing them to spread
The population of an alien species can grow rapidly if the number of pathogens if leaves behind in its native range exceeds the new pathogens it accumulates in its naturalized range
On average, plants living in their naturalized range had 84 % fewer fungi and 24 % fewer virus species than did individuals liing in their native range.
What does this mean? EASIER TO BECOME INVASIVE!
A term that refers to any species that is in danger of extinction throughout all or a significant portion of its range
Endangered plant species are most abundant where biomass is relatively low
Availability of phosphorus has increased in some areas which has led to a decrease in plant biodiversity
Humans hunt and harvest many plant and animal species
If the rate of hunting/harvesting exceeds the max. sustainable yield, the populations could decline
This can lead to EXTINCTION!
The arrival of aboriginal human populations in Australia about 30,000 years ago contributed to the extinction of many large mammals
Marsupial lions
Kangaroos that reached 8 feet tall
Hunting now extends well beyond the need for food
Def: The process in which people try to reduce the populations of species that compete with humans for crops or game.
Ranchers complained that their livestock was being killed off by wolves, mountain lions, and eagles
U.S. federal and state governments used to pay hunters to kill top-level predators
Illegal killing or collecting of plants and animals.
Examples:
Rhino horns can sell for thousands of dollars in the Middle/Far East (daggers/medicine)
Bright Blue Hyacinth Macaw (world’s largest parrot) sells for up to $8,000
If society is willing to spend money to preserve biodiversity, how can this money be directed to save the greatest amount of biodiversity?
Society to allocate its preservation efforts so that the benefits associated with the last species saved equal the effort spent saving it
Scientists have developed four criteria to choose among efforts to preserve biodiversity:
1. Examines how distinct a species is
2. Examines the usefulness of a species
3. The degree to which human actions can reduce the probability that a species will go extinct
4. Society must evaluate the cost of preserving a species
Higher priority is given to unique species
Ranking based on their potential contribution to the growing collection of genetic knowledge
Genetically unique species may contain info that is not available in other species
Can be either commercial value (wild salmon) or the degree to which humans like the species (bald eagle, panda, etc.)
What are the odds that the species will go extinct if society does nothing?
If some effort is expended, will that effort lower the probability of that species going extinct?
It doesn’t make sense to help a species unlikely to go extinct or one that will definitely become extinct regardless of intervention
Conservation efforts for some species may be small compared with the effort required to save others
Try to preserve the greatest biodiversity for the least cost
Policy makers have 3 general approaches to preserving biodiversity:
Legal protections
Ecosystem protections
Market-based mechanisms
Endangered Species Act of 1973 Authorizes the US Fish and Wildlife Service and the
National Marine Fisheries Service to protect endangered and threatened species
Prohibits hunting or commercial harvesting
Mandates habitat protections
Any threat supersedes all economic activities regardless of their value
Any species that is likely to become an endangered species in the foreseeable future throughout all or a significant portion of its range.
Once listed, they compete for federal and state funds aimed at preservation
Unfortunately large sums have been spent to protect “popular” species (bald eagle) and much less has been spent on other species (lizards, amphibians, etc.)
1973 Convention on International Trade in Endangered Species
At the start of 2006, more than 160 parties had entered the convention
Monitors and regulates international trade of endangered plants and animals (products made from them)
Effectively reduced trade in ivory, pelts, and other products that threaten certain species
Ex situ conservation: maintaining a species away from its habitat
Breeding animals in zoos or aquariums
Storing genetically diverse plants in seed banks
In situ conservation: efforts to preserve species in functioning ecosystems Preserving habitat
Convention on Wetlands of International Importance 1971 540 listed wetlands covering 32 million hectares
Signed 1972 in Paris
Convention designates protected areas as World Heritage Sites
Ex.) Everglades National Park in Florida
Ex.) Archaeological remains in Petra, Jordan
Almost 100 world heritage sites throughout the world
1993 set a goal of preserving 10% of the land surface that is covered by each of the fourteen major biomes
In 2003, they announced that protected areas covered 11.5% of Earth’s land surface in 9 out of the 14 biomes
Private organizations that pursue activities to relieve suffering, promote the interests of the poor, protect the environment, provide basic social services, or undertake community development
Raise money and make agreements with national governments to preserve land
Joins with governments, private corporations and individuals, nonprofit organizations, and indigenous people to purchase land they deem critical to biodiversity
Managed with respect to land and marine conservation, freshwater supplies, global climate change, fire, and invasive species
As of 2005 117 million acres of land, 5,000 miles of rivers, and established over 100 marine conservation projects
Species whose range falls outside of protected species
Most live in tropical areas
Range of many species does not coincide with protected areas
Scientists recommend that global network of protected areas be expanded based on geographic patterns of biodiversity
Some efforts to preserve biodiversity use market forces
Provides economically valuable goods and services
If policy can make consumers pay for these goods and services, these payments would serve as an incentive to preserve biodiversity
One of the most successful market-based mechanisms to preserve biodiversity
Tourism contributing to the conversation of natural environments that is planned, developed, and operated with local communities in a way that contributes to the well-being of local communities
Entrance fee is currently $5, questionnaire filled out by foreign tourists indicated that an entrance fee of about $47 would maximize the funds earned by local inhabitants
Local people cannot use for agriculture, so extra fees would help them out
Uncertainty about who owns the genetic info of biodiversity
Constant struggle between government and pharmaceutical companies
Agreement has been made between pharmaceutical companies and nations with high biodiversity
One of world’s largest drug companies recently paid $1.35 million to Costa Rica for the rights to the genetic info of local species
Allows Merck to comb local forests, looking for species with characteristics that can be used to produce marketable drugs
Should Merck be successful, Costa Rica would get a royalty
A market where goods or services are sold illegally
High price provides an incentive for poaching
Lack of legal market means there is no economic incentive to preserve the endangered species’ habitat
Caused by prohibiting the hunting or trade of an endangered species tends to drive up the price for a species
If a well-regulated market can be established, prices for the protected species can be reduced
Landowners will be willing to set aside habitat for endangered species
Bee Ted talk: http://www.huffingtonpost.ca/2016/03/15/honey-nut-cheerios-bee-missing_n_9473778.html
Small pox reading: http://www.npr.org/sections/health-shots/2014/05/09/310475511/keep-or-kill-last-lab-stocks-of-smallpox-time-to-decide-says-who