response to change What happens to an ecosystem when it is disturbed?
Ecosystem Changes Ecological change is referred to as Succession the regular pattern of changes over time in the types of species in a community Interactions among living things results in these changes First organisms to arrive, usually small plants, are called pioneers The end result of these changes, if left undisturbed, is the climax community
What types of animals would you expect to inhabit each stage?
Animals in succession As succession occurs, the animals correspond to the plants that are present Small animals (insects, things that live in soil, small rodents) that eat the pioneer species appear first Then larger animals that eat the smaller animals and/or the next plant species appear This continues until you have the climax group of animals as well as plants
Types of Succession Two types depending on how it starts: Primary Succession – new land is created and succession begins Takes much longer (no soil!) Example: volcanic eruption creates land; bare rock exposed from melted glacier weathering plays a major role in creating soil
Photos taken by Mrs. McCurdy 1998 Its eruption in 1980 destroyed large areas of forest. In 1988 J. Alean documented the starting re-colonization of the terrain by plants, and in 2001 the photos were repeated. Photos taken by Ms. McClure 2006
Types of Succession Secondary Succession – changes occur on land where an existing ecosystem has been destroyed Happens faster Examples: Forest Fire, abandoned farm fields, land left alone for many years
Succession in aquatic ecosystems called eutrophication the gradual change of an aquatic ecosystem into a terrestrial (land) ecosystem as organisms die in the aquatic ecosystem, they fall to the bottom and gradually fill in the pond/lake/river basin different species of plants (like cattails or cottonwood trees) will start to grow on the edges, continuing the process
Eutrophication humans GREATLY speed up this process by polluting the water ways with nitrogen and phosphorus found in many common products like fertilizer, laundry detergent these elements cause increased plant growth and more rapid animal death also speeds up with increased temperatures
Three Categories of Human-Induced Environmental Problems #1 Resource Depletion Natural resources become depleted when a large part of it has been used up. Natural Resources can be either: Renewable - they are constantly being replaced trees, water, crops, sun Nonrenewable - they cannot be replaced (or replenish too slowly) animal and plant species, fossil fuels, minerals
Results of Resource Depletion Deforestation: cutting large areas of trees for use in building products, fuel, etc. or to use the land for other purposes. Desertification: destructive use of land results in the formation of desert conditions Sustainable use can prevent both of these
Human-induced environmental problems #2 Pollution Pollution is the introduction of harmful levels of chemicals or waste material into the environment Pollution may be harmful to human health Pollution can occur in air, soil, or water Pollution can take the form of liquid, solid, gas, or even energy
Results of Pollution Acid Precipitation – rain/snow/ice that has a pH less than 7. Results from sulfur oxides and nitrogen oxides in the atmosphere mixing with the water in the atmosphere to form sulfuric and nitric acid. Dangerous to living things – pH in environment may become intolerable Destructive to environment – acid dissolves certain types of stone
Results of pollution Biomagnification – process by which a chemical moves through the food chain, becoming more concentrated. May be harmful/lethal to organisms at the top of the food chain, reducing biodiversity.
Biomagnification video - MUST SEE
Human-induced environmental problems #3 Extinction Extinction means the last individual of a species has died and the species is gone forever Thousands of species are becoming extinct each year Endangered species are those whose extinction is very close, and will happen without some sort of intervention
A sustainable world In a sustainable world, human populations can continue to exist with a high standard of living and health because Biodiversity is preserved Habitats are preserved Nonrenewable resource are used sparingly and efficiently Renewable resources are used no faster than they can be replaced There are enough resources for the next generation
Biodiversity is preserved Biodiversity – all of the different forms of life All living things are connected, and therefore depend upon each other for survival. Three Levels: Species diversity – all of the different species in an area Genetic diversity – all of the different genetic combinations in a particular species Ecosystem diversity – all of the different biological, geological, chemical factors in an area
Habitats are preserved Destruction of appropriate habitat can lead to extinction Habitat fragmentation – some living things require large areas of land. Habitat can be come “fragmented” when human development separates areas. Invasive species– occurs when a species is introduced to a habitat in which it is not naturally found. If there is no predator for that species, it may increase in number at the expense of native species, who will now have to compete for resources
Global Changes occur when ecosystem is disrupted over long periods of time Ozone Depletion – reduction in the thickness of the ozone layer Ozone (O3) – located in the stratosphere, filters UVB light before it reaches the earth Ozone is broken down into oxygen gas (O2) by CFC’s (chlorofluorocarbons) Why does this matter? UVB has been linked to skin cancer, cataracts, damage to materials like plastics, and harm to certain crops and marine organisms. Reduction in ozone means an increase in UVB!
Ozone “hole” September 2009
Global Changes (Continued) 2. Global Warming: increase in the average temperature of the Earth Dependent on the greenhouse effect – the Earth is warmed because the gases in the atmosphere trap heat Greenhouse gases: Carbon dioxide Methane Surface Ozone CFC’s Nitrous oxides
Temperature and Carbon Dioxide In historical data, temperature and carbon dioxide levels have been closely connected
Results of Increased Global Temperatures Sea level rise Loss of habitable land Coral bleaching Shoreline erosion Changes in agriculture May be positive or negative Appropriate growing climate may shift Changes in water resources Areas of drought/flooding as weather patterns change
IF nonrenewable resource are used sparingly and efficientlyAND renewable resources are used no faster than they can be replaced
There will be enough resources for the next generation Sustainable Use of Natural Resources: More efficient technology to produce electricity Increase use of alternative energy sources Increase fuel efficiency in automobiles Conservation: the act of reducing the amount of resources one consumes. 3 R’s – reduce, reuse, recycle