Human Impact on the Environment The Human Population

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 Coal Fossil fuels

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 p. H(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 layerprevents lethal doses of UV radiation from reaching earth • Thinning of ozone caused by release of CFC’s (chlorofluorocarb ons) 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/di saster-in-the-gulf-the-oil-spillenvironmental-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.