HW 26NOV14 article zoonoses

Article 2

BIODIVERSITY Animal diseases intensified by climate change

From Bluetongue disease in sheep to Rift Valley, Fever in camels, researchers say that animal diseases are sparked and spread by climate change. What causes them, and what can people do to prevent them from spreading?

Bluetongue is transmitted by a tiny biting midge, Cullicoides immitus, similar to the way that malaria is spread by mosquitoes.

Sheep with swollen, bright blue tongues: it is a surreal sight only recently spotted in Germany.

Aptly dubbed Bluetongue, the deadly disease causing the coloration was previously well known in veterinary medicine as a virus specific to Africa, says Heribert Hofer, the director of the Leibniz Institute for Zoo and Wildlife Research at Free University of Berlin. It particularly occurs in sheep, cattle and goats.

Yet over the past 10 years, several cases have been reported throughout Western Europe due to an increase of the warm and wet temperatures where the disease thrives. To date, it’s killed more than 1.5 million sheep in Europe.

"Climate change makes it easier for the pathogen to spread beyond its normal places," says Hofer. "In places where it exists already, it might become more severe."

Bluetongue is one of a number of climate-affected diseases impacting the health of animals. Scientists such as Hofer say they will become more prevalent due to rising temperatures.

Animal diseases are a "canary in a coalmine", or an early-warning indicator of a greater problem at hand, says Matthew Bylis, head of Liverpool University’s Climate and Infectious Diseases of Animals (LUCINDA) group. Two-thirds of human diseases originate in animals, about half of which are farm animals.

Bluetongue is transmitted by Cullicoides immitus, a tiny biting midge, similar to the way that malaria is spread by mosquitoes.

Changing the rules of the game for pests

 Scientist examining a salamander

Bd, chytrid fungus deadly to European salamanders and newts, spreads more quickly under cooler temperatures.

Pests such as the biting midges, mosquitoes and flies used to be fenced into a specific geographic range or habitat type by climatic factors. Many of them thrive the warmer it gets, but then can no longer persist at higher altitudes. That’s quickly changing, though, says Richard S. Ostfeld, a senior scientist at the Cary Institute of Ecosystem Studies in Millbrook, New York.

"The concern is that, as there are places on the planet where conditions are currently too cold for the vectors to occur," says Ostfeld. "As the climate warms, the vectors will spread into those new areas and there will be a net increase in their geographic ranges."

Warming temperatures are giving these insects a competitive advantage, according to a 2011 article by Harvard University health researchers Samuel S. Myers and Aaron Bernstein. It is not only speeding up the rates of reproduction, development, survival and biting of blood-feeding pests, but is also shortening the parasite development time inside these disease-transmitters.

"Even though the actual change in temperature has not been very large, from our perspective, from the perspective of an insect, a pathogen in an insect is quite substantialbecause they’re so much more sensitive to climate," says Baylis. "All insects are affected by temperature and rainfall."

Take Rift Valley Fever, a virus transmitted by mosquitoes that has recently spread throughout Africa and the Middle East due to rainfall increases of up to three times their average annual rate. It has caused mass fatalities in camels, cattle, goats and sheep, and impacted the livelihoods of the farmers that depend on them.

Climate change also prompts behavioral changes of animals that make them more susceptible to disease, says Baylis. For example, during periods of drought animals will cluster together more at waterholes. The close proximity will allow diseases to spread more – and the animals, often in worse physical condition, will be unable to resist them.

Yet it’s not just warming, but climate fluctuations as a whole, which are sparking the spread of disease. There are a number of species of fungi, a couple of which serve as wildlife pathogens, which bode better under colder conditions.

Take the so-called Bd, a recently identified chytrid fungus deadly to European salamanders and newts, as well as frogs and toads worldwide. The lethal skin disease threatens more than 200 amphibian species around the world.

"Bd has been shown to not spread as rapidly or proliferate as rapidly under warm conditions," says Ostfeld, pointing out that higher temperatures are also known to reduce the ability of some amphibians to fight off infection. "So the fungus is actually assisted by cooler conditions."

Like most species, these amphibians evolve to adapt to changes in their environment -- but sometimes the change is too fast for them to keep up with. Thus, animal populations and their geographic ranges will shrink due to disease.

Impacting biodiversity

Bluetongue Disease, which started in Africa, has spread in the last decade to Europe and killed more than 1.5 million sheep there.

Infectious diseases in animals will have a more profound impact on biodiversity than has previously been realized, says Hofer.

"We recognize that infectious disease pathogens are a major force shaping not only the ecology of natural ecosystems, but also the evolution of species, their ability to handle challenges, and the development of new species," he says.

Combating these issues requires massive investment, training, and development of vaccines, says Ostfeld.

Species do move, and they can shift their positions in response to changing conditions, he adds. Yet the rate of climate change "is so fast right now",  that in many cases neither evolutionary change nor behavioral change is sufficient to keep up.

"Whatever we can do to slow things down," says Ostfeld, "we’re going to give untold numbers of species a fighting chance to adapt rather than disappear."

Vocabulary

Ecosystem

Profound

Impact

Biodiversity

Proximity

Altitude

Climate

Precipitation

Malaria

How does climate have an impact on disease spread?

How does the ability of animals to travel cause disease to spread?

Midterm Review

Topics
Ch 4,5, and 6

Test Practice

Text

http://www.nexuslearning.net/books/Holt_Env_Science/

Video Support
Ecosysytems

Midterm Environmental2014 Study online at quizlet.com/_zl7vb

1.abiotic factors: Describes the nonliving part of the environment, including water, rocks, lights, and temperature.

2.adaptation: A trait that helps an organism survive and reproduce

3.altitude: generally a decrease in temperature with height above sea level

4.biomes: Areas with similar temperature, precipitation, altitude,soil, plants, and animals

5.biotic factors: All the living organisms that inhabit an environment.

6.carbon cycle: Circulation and reutilization of carbon includes photosynthesis and respiration.

7.cellular respiration: Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

8.consumers: An organism that obtains energy and nutrients by feeding on other organisms or their remains.

9.decomposers: Fungi and bacteria that break complex organic material into smaller molecules

10.dynamic equilibrium: A state of balance between continuing processes.

11.evolution: Change in a kind of organism over time; process by which modern organisms have descended from ancient organisms.

12.food chain: A diagram showing how energy passes from one organism to the next in an ecosystem

13.latitude: measuring north and south of the equator (0 degrees); primary element of climate

14.natural selection: A natural process resulting in the evolution of organisms best adapted to the environment.

15.nirtogen cycle: Essential to life because it is necessary for the manufacture of proteins and DNA. One of the most important and complex cycles

16.nitrogen cycle: A major nutrient cycle consisting of the routes that nitrogen atoms take through the nested networks of environmental systems.

17.photosynthesis: Carbon dioxide + water ----> glucose + oxygen

18.precipitation: A form of water (e.g., hail,rain,sleet,snow), that condenses in the atmosphere and fall to Earth's surface.

19.producers: A group of organisms that produce their own food through photosynthesis.

20.transpiration: Evaporation of water from the leaves of a plant

Diversity of life

Ecosystems 

Biomes


Natural selection is the process by which individuals that have favorable variations and are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do.
Darwin proposed that over many generations, natural selection causes the characteristics of populations to change.
Evolution is a change in the characteristics of a population from one generation to the next.

Ch 4 ecosystem, 93 biotic factor, 94 abiotic factor, 94 organism, 95 species, 95 population, 95 community, 96 habitat, 96 natural selection, 97 evolution, 97 adaptation, 99 artificial selection, 100 resistance, 101 bacteria, 102 fungus, 103 protist, 104 gymnosperm, 105 angiosperm, 105 invertebrate, 106 vertebrate, 107	Main Ideas  Ecosystems are composed of many interconnected parts that often interact in complex ways.  An ecosystem is the community of all the different organisms living in an area and their physical environment.  An ecosystem contains biotic (living) and abiotic (nonliving) components.  Organisms live as populations of one species in communities with other species. Each species has its own habitat, or type of place that it lives. The naturalist Charles Darwin used the term natural selection to describe the unequal survival and reproduction that results from the presence or absence of particular traits.  Darwin proposed that natural selection is responsible for evolution—a change in the genetic characteristics of a population from one generation to the next.  By selecting which domesticated animals and plants breed, humans cause evolution by artificial selection.  We have unintentionally selected for pests that are resistant to pesticides and for bacteria that are resistant to antibiotics. Organisms can be divided into six kingdoms, which are distinguished by the types of cells they possess and how they obtain their food.  Bacteria and fungi play the important environmental roles of breaking down dead organisms and recycling nutrients.  Gymnosperms are evergreen plants, many of which bear cones, while angiosperms produce flowers and bear seeds in fruit.  Insects, invertebrates that are the most successful animals on Earth, affect humans in both positive and negative ways.  Vertebrates, or animals with backbones, include fish, amphibians, reptiles, birds, and mammals.
Ch 5 photosynthesis, 117 producer, 118 consumer, 118 decomposer, 119 cellular respiration, 120 food chain, 122 food web, 122 trophic level, 122 carbon cycle, 124 nitrogen-fixing bacteria, 126 nitrogen cycle, 126 phosphorus cycle, 127 129 primary succession, 129 secondary succession, 129 pioneer species, 130 climax community, 130	Main Ideas  The majority of the Earth’s organisms depend on the sun for energy. Producers harness the sun’s energy directly through photosynthesis, while consumers use the sun’s energy indirectly by eating producers or other consumers.  The paths of energy transfer can be followed through food chains, food webs, and trophic levels.  Only about 10 percent of the energy that an organism consumes is stored and transferred when that organism is eaten. Materials in ecosystems are recycled and reused by natural processes.  Carbon, nitrogen, and phosphorus are essential for life, and each of them follows a recognizable cycle.  Humans can affect the cycling of materials in an ecosystem through activities such as burning fossil fuels and applying fertilizer to soil. ecological succession, Organisms in an environment sometimes follow a pattern of change over time known as ecological succession.  Secondary succession occurs on a surface where an ecosystem has previously existed. Primary succession occurs on a surface where no ecosystem existed before.  Climax communities are made up of organisms that take over an ecosystem and remain until the ecosystem is disturbed again.
Ch 6 Key Terms biome, 143 climate, 144 latitude, 145 altitude, 145 Main Ideas emergent layer, 148 canopy, 148 epiphyte, 148 understory, 148 temperate rain forest, 151 temperate deciduous forest, 152 taiga, 153 tropical rain forest, 146 savanna, 155 temperate grassland, 156 chaparral, 158 desert, 160 tundra, 162 permafrost, 162	Scientists classify the ecosystems of the world into large areas called biomes.  Biomes are described by their plant life because the plants that grow in an area determine what other organisms live there.  Temperature, precipitation, latitude, and altitude are factors that affect climate, which determines the types of the plants that can grow in an area. The major forest biomes include tropical rain forests, temperate rain forests, temperate deciduous forests, and taiga.  Tropical rain forests receive heavy rains and high temperatures throughout the year. They receive about 200 to 450 cm of rainfall a year. They are the most diverse of all biomes.  Temperate deciduous forests experience seasonal variations in temperature and precipitation. They receive 75 to 125 cm of precipitation a year.  Forest biomes are threatened by deforestation through logging, ranching, and farming. Savannas are located north and south of tropical rain forests and have distinct wet seasons. Savannas receive 90 to 150 cm of precipitation a year.  Temperate grasslands get too little rainfall to support trees. Grasslands are dominated mostly by different types of grasses and flowering plants. Shortgrass prairies receive about 25 cm of precipitation a year.  Deserts are the driest biomes on Earth. Deserts receive less than 25 cm of precipitation a year.  Plants and animals found in each biome adapt to the environment in which they live.