Human Impact on the Environment

The Human Population The growing human population is exerting pressure on Earth’s natural resources We are using the non renewable resources at a faster rate than can be created Renewable resources are being used, but not at the same rate as non renewable.

Types of Resources Renewable: replaced by natural processes Ex: plants/crops, water

Types of Resources Nonrenewable: only available in limited amounts and take a long time to form. Formed from carbon forms ofdead organisms Ex: Metals, minerals, topsoil, fossil fuels Fossil fuels Coal

Types of Pollution Pollution: contamination of soil, water, air Industrialization- a major source of pollution.

Types of Pollution Air Pollution: Primary cause is burning of fossil fuels for electricity Other contributors- cars, heating homes, planes Particulates-solid particles of soot Smog-smoke, gases, fog

Air Pollution Acid rain- Sulfur oxides and water mix to form sulfuric acid that falls to earth and lowers pH(6 and below) of streams/lakes, leaches nutrients from the soil

Results of Acid Rain Upsets the environmental conditions that living things are in Can result in death of organisms that require a highly specific environment to thrive in

Air Pollution Greenhouse effect- Increased Carbon Dioxide: from increased burning of fossil fuel Most of the greenhouse gases leave but in excess they build up and warm up the Earth Leads to global warming- Earth becomes warmer over time due to change in carbon dioxide level

Air Pollution Ozone layer- prevents lethal doses of UV radiation from reaching earth Thinning of ozone caused by release of CFC’s (chlorofluorocarbons) into the atmosphere.

Types of Pollution Water Pollution: Contaminants from sewers, industry, homes, farms Pollutants (e.g. fertilizers, pesticides, wastes) trickle down into ground water; More efforts being made to correct these problems

Water Pollution Types Point pollution- from a single source and easily identifiable Example- factories

Water Pollution Non-point pollution- from many sources and not easily identifiable Example- homes, lawns, highways, pesticides, fertilizers

Impacts of Pollutants in Ecology Biomagnification – as pollutants move up a food chain, its concentration increases

Results of Biomagnification As the pollutant or toxin is taken into an organisms body it enter its cells As higher order organisms obtain energy from lower order organisms, the pollutant/toxin is passed on and magnified due to the organisms usually increasing in size moving up a food chain/web. Results in overall magnification of the toxin through the chain or web

The Gulf Oil Spill Disaster http://planetgreen.discovery.com/videos/disaster-in-the-gulf-the-oil-spill-environmental-impact.html

What can be done? Three R’s of conservation

Human Impact Effects on Plants and Animal Life Biodiversity- the variety of life in an area Most diverse areas of the world are tropical rainforests Biodiversity is being lost due to human actions like deforestation, overhunting, overfishing, introducing a species

How do we negatively impact biodiversity? Deforestation: clearing of trees for open land space loss of animal habitat and niches Overhunting/overfishing interrupt predator prey relationships by influencing population dynamics Introduced Species: when we introduce a new species that does not have a natural predator overpopulation of that new species occurs. May take over other organisms niche, habitat, food resource

Effects of An Introduced Species

Importance of biodiversity Loss of species may have consequences for others living things (e.g.food chains and webs are disrupted)

Plant and Animal Responses To A Changing Biosphere Plants tropism and normal adaptation responses may be altered due to drastic environmental changes Animals Normal animal behavior may be altered due to drastic environmental changes

PLANT RESPONSES & ADAPTATIONS: Tropism: Plant’s response to its environment Geotropism- Response to gravity; roots down, stems up Phototropism- Response to light; sunflower “heads” turning toward sun Thigmotropism- Response to touch; vine climbing trellis Hydrotropism- the way a plant grows in response to water

PLANT RESPONSES & ADAPTATIONS: Auxins- Hormones regulate tropisms Gibberellin- causes plant growth Abscisic acid- inhibits plant growth

Normal Plant Responses and Adaptations Plant Adaptations: Dormant in drought Deciduous trees- Drop leaves in winter Thick bark to protect from fire Flexible branches of conifers to bend with ice and snow Cuticle- waxy coating on needles (leaves) “hitchhiker” seeds, some blow in wind, float, etc to disperse seeds bright colors and fragrance in flowers to attract pollinators nutrient exclusion – some plants aren’t worth eating (no nutritional value) These adaptations may be challenged due to a changing biosphere

Normal Animal Behavior: Inherited or innate behavior- automatic responses, reflexes, and instincts Ex: courtship, spider web, nest building, response to heat, blinking Territorial behavior-: aggression, defend/ mark territory, efficient use of resources, decreases competition

Animal Behavior: Migration: instinctive, seasonal movement; affected by hormones, length of day, changing environmental conditions, geographical clues, use of magnetic field Hibernation and Estivation: Long term vs short term lowered metabolism, stimulus – winter vs shorter periods of drought or lack of food

Animal Behavior: Learned Behavior: Habituation (deer feeding in yards), imprinting (turtles and salmon returning to birthplace to reproduce/spawn)

Animal Behavior Adaptations for defense: Mechanical defenses: physical structures like claws, teeth, sharp tusks, stingers, shells

Animal Behavior Camouflage: blend with environment cryptic coloration- same color or pattern as background Disruptive coloration- color patterns disguise silhouette, ex- herd of zebra Countershading two-toned, Ex- fish dark on top, light on bottom

Animal Behavior Schools and Herds- big group confuses predators

Animal Behaviors Chemical Defenses: neurotoxins, poisons, venom, poisonous fish; bombardier beetles, wasps and bee stings, plants foul tasting chemicals

The Overall Bottom Line Our actions not only affects our species, but all other factors (biotic/abiotic) that are on Earth. The more damage we do to our biosphere (Earth) by our actions, the longer it will take for it to be fixed. Actions must be taken now so that we save what we have on Earth.