IMPACT OF HUMAN ACTIVITY ON THE ECOSYSTEM

HUMAN IMPACT 1: Pollutants Pollutant #1: Synthetic Chemicals (Man made) Build up in environment because decomposers can’t break them down. Bioaccumulation: Build up of chemicals in the bodies of living organisms (food, respiration, skin contact). Affects the Nervous System, Immune System, Reproductive System (can cause birth defects, infertility) Levels get too high, can lead to fatality

KEYSTONE SPECIES Bioaccumulation can have major effects on an ecosystem if it affects a KEYSTONE SPECIES a species that has a disproportionately large effect on its environment relative to its abundance. Salmon, Bears, Wolves, Beavers etc. If a Keystone species is effected by pollution, then whole ecosystem can be damaged.

BIOMAGNIFICATION Chemicals don’t just accumulate in the individual (bioaccumulation), the concentration rises at each trophic level (biomagnification) Pollutants accumulate and are stored in plant/animal tissue. When organism gets eaten, the trapped pollutants also make their way up the food chain.

Pollutant #2: PCB’s (Polychlorinated biphenyls) Synthetic chemicals used in paints, plastics, etc. (Banned 1977) Problem: PCB has a long half-life- meaning they don’t break down, and can effect organisms for a very long time! Aquatic organisms are very sensitive to PCB’s (e.g. Orcas)

POLLUTANT #3: POP (Persistant Organic Pollutants) Come from insecticides, pesticides. DDT- pesticide introduced in 1941 to kill disease carrying mosquitoes. However, binds to soil, and does not breakdown for 15 years. Bioaccumulates in plants, magnifies in other organisms.

PPM- Parts per million When we say ppm- we mean the number of particles in a million particles. 1ppm of DDT = one molecule of DDT in a million particles of other substances (typically water) DDT is toxic if it is more than 5ppm!!

Pollutant #4: Heavy metals Metallic elements toxic to organisms at very low concentrations Ex1. Lead- found in oils, paints, insecticides, electronics for radiation shielding) Ex2. Cadmium- found in plastics Ex3. Mercury- found in burning of fossil fuels, waste incineration, mining and battery production

HUMAN IMPACT #2: Encroachment Taking over the habitats of other organisms. ENCROACHMENT #1. LAND USE- how humans use land for urban development, agriculture, industry etc. ENCROACHMENT #2. RESOURCE USE- How we obtain, and use naturally occurring materials (e.g. coal, oil, gold, aluminum, lumber, etc.) ENCROACHMENT #3. HABITAT LOSS- Refers to loss of Habitat due to human activities.

ENCROACHMENT #4. HABITAT FRAGMENTATION- Splitting of large habitats into smaller ones (disrupting natural activities for plants/animals) ENCROACHMENT #5. DEFORESTATION- clearing or logging of forests for human use. Problem 1. Resulting barren land is planted with agricultural crops (usually one species- one gets sick ALL GET SICK!) REDUCES BIODIVERSITY! Problem 2. Soil Degredation (erosion of topsoil so plant’s can’t grow)

Encroachment #6 agriculture Exposed fields (non-planting seasons) can allow for soils to become eroded and more compacted (farm vehicles and animals stepping over it). Less room for water to get in, farmers have to add more and more holes to the soil for aeration. This can lead to increased pesticide uptake, and poor soil conditions.

HUMAN IMPACT #3: Exploitation RESOURCE EXPLOITATION Taking natural resources for jobs, materials, food, shelter and energy. Can lead to habitat loss, soil degredation, and contamination of water. OVEREXPLOITATION Extraction of resources until they are gone. Can result in extinctions, greatly effecting food webs (especially if a Keystone species)

HUMAN IMPACT #4. INTRODUCTION OF NON-NATIVE SPECIES Native Species: organisms that typically inhabit a particular biome or region. Non-native species: (introduced/foreign species) are organisms that have accidentally or intentionally been let loose into biomes that they normally do not live in. What do you think might happen??

What problems can non-native species bring in? NOT ENOUGH FOOD/RESOURCES TO GO AROUND ORGANISMS WILL COMPETE FOR RESOURCES (HARMFUL INTERACTION BETWEEN TWO OR MORE ORGANISMS COMPETING FOR FOOD, SHELTER, ETC.)

INVASIVE SPECIES Species that invade and can take over the habitat of native species, or invade the bodies of organisms (weakening their immune system) Invasive species increase predation (where an organism devours another) Can cause DISEASE EPIDEMICS (more crowded)

WHAT DOES IT ALL MEAN?? ALL of these factors we have just discussed are having major impacts on both the biotic, and abiotic factors of our environment. Climate change is occurring, average global temperatures are rising We are in the “Sixth Major Exctinction” – most rapid rate of extinction in Earth’s History What can we do to slow it all down??

Sustainable practices process for meeting human development goals while maintaining the ability of natural systems to continue to provide the natural resources and ecosystem services upon which the economy and society depend

Parting words “Unless someone like you cares a whole awful lot, things are not going to get better, they are not.” -Dr. Seuss, The Lorax