Environmental Science Exam 2

Ecology

the study of the interactions among organisms and with their environments, and includes many levels.

Ecological Levels of Organization

Individual

Population

Community

Ecosystem

Landscape

Biome

Population Size

the number of individual organisms. May be for a given area and time.

Population Density

the number of individuals per unit area.

Population Distribution

The spatial arrangement of organisms within an area:

Random

Uniform

Clumped

Age Structure

describes the number of individuals of different ages within a population

Population Growth Rate

(birth rate + immigration rate) - (death rate + emigration rate)

Exponential Growth

“J” Shaped Curve, Unregulated Population Growth.

Logistic Growth

“S” shaped Curve, Constrained Population Growth.

Density Dependent Factors

rise and fall with population density. Exp: Predation Disease.

Density Independent Factors

is unaffected by population density. Exp: Temperature Extremes, Natural Disasters.

Carrying Capacity

the number of people, other living organisms, or crops that a region can support without environmental degradation.

Natural Selection

Based on 3 Requirements:

• Individuals must vary in some trait.

• Trait variation must be heritable.

• There is a selective pressure on the survival and reproduction of organisms related to this trait.

Speciation

How natural selection and evolution can create new species

Ecological Diversity

Variety of ecosystems, habitats, or communities

Species Diversity

Variety of species in an area.

Richness: the number of species

Evenness: the relative abundance of species

Genetic Diversity

Variety of DNA compositions in a population

Benefits of Biodiversity for humans

Enhances Food Security, Provide Drugs and Medicine, Provides Ecosystem Services, Maintains Functioning Ecosystems, Boosts Economies, People Value Connection With Nature.

Today’s Extinction Event

Cause by humans: Habitat Loss, Pollution, Overexploitation, Introduced Species and Disease, and Climate Change

Conservation Biology

field that seeks to understand the loss, protection, and restoration of biological diversity.

Efforts to Save Species

Captive Breeding, Cloning, and Forensic Science.

Strategies to Save Habitats, Communities, and Ecosystems

Biodiversity Hotspots, Parks and Preserves, Ecological Restoration, and Community-Based Conservation.

Critter Chronicles

Extinct Species: Tasmanian Tiger

Newly Discovered: Olinguito

Endangered Species: Red Panda

Environmental Health Goals

Minimize risks of encountering hazards, lessen impacts of hazards that are encountered.

Types of Environmental Hazards

Physical, Chemical, Biological Hazards,

Non-Infectious Diseases

Develop without the action of a foreign organism. Exp: Cancer

Infectious Diseases

A pathogen must infect a host. Through skin, respiratory system, or digestive system. May spread through a vector: a mosquito carrying malaria.

Toxicology

The science of examining the effects of poisonous substances on humans and other organisms.

Toxicant

substance that acts a poison to humans or wildlife.

Toxin

a toxic chemical manufactured in the tissue of living organisms, often as a defense.

Toxicity

the degree of harm caused by a toxicant

Carcinogen

Cause cancer

Mutagen

Cause genetic mutations

Teratogens

Cause birth defects

Neurotoxins

Damage the nervous system

Allergens

Overativate the immune system

Pathway inhibitors

Block steps in important biochemical pathways

Silent Spring

Book published in the 1960s that talked about the dangers of DDT

Natural Defenses to Toxic Substances

Skin, scales, feathers, and metabolic pathways.

Bioaccumulation

Concentration of substances in animal’s tissues

Biomagnification

Concentration of substances through consumption of other organisms

DDT in LA

Several large containers of DDT were thrown into the ocean off the coast of LA and they are only now being discovered and their effects investigated.

Case History

Observe and analyze individual patients

Epidemiological Studies

Large-scale comparisons of groups of people

Dose

Amount of substance the organism receives

Response

Magnitude of toxic effects the organisms exhibits due to the dose.

Synergistic Effects

Occur when the interactive impacts of chemicals are greater than the sum of their individual effects.

Risk Management

Consists of decisions and strategies to minimize risk based on comparisons of costs and benefits

Dr. Louis Guillette

Found hormonal imbalances in Alligators exposed to pesticides

Dr. Tyrone Hayes

Studied Atrazine effects on frogs

Functions of Atmosphere

Moderates climate, provides oxygen, shields us from meteors and solar radiation, transports and recycles and nutrients.

Layers of Atmosphere

Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere.

Circulation Cells

Sun’s energy is absorbed and fuels evaporation.

• Warm air rises (because it’s less dense).

• This air is also moist.

• As warm, moist air rises, it cools, which causes the water to condense and be released as rain.

• Cool air is denser than warm air, so it sinks back down to Earth’s surface.

• The cycle repeats.

Temperature Inversions

Layer of cool air is trapped beneath warm air. Prevents any vertical mixing from occurring. Traps pollution.

Natural Air Pollutants

Fires, Volcanic Eruptions, Dust Storms.

7 Major Human Pollutants

Carbon monoxide, sulfur dioxide, nitrogen oxide, particulate matter, volatile organic compounds, ammonia, and lead.

Improving Indoor Air Quality: Higher Income Nations

Reduce exposure to cigarette smoke (e.g., by not smoking). Test for radon and mold spores. Minimize exposure to sources of VOCs.

Improving Indoor Air Quality: Lower Income Nations

Introduce cleaner-burning fuels and stoves.

Smog

general term for an unhealthy mixture of air pollutants that accumulate from fossil fuel combustion.

Industrial Smog

Specific type of smog in cities

Photochemical Smog

forms when sunlight drives chemical reactions between primary pollutants and atmospheric compounds.

Stratospheric ozone depletion

When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules

Acid Deposition

Deposition of acid or acid-forming pollutants from the atmosphere on the Earth’s surface.

Urbanization

shift of human populations into towns and cities.

Sprawl

Spread of low-density urban, suburban, or exurban development outward from an urban center

Causes of Sprawl

Constrains Transportation, Increases Pollution, Decreased Physical Activity, Less Land is left Undeveloped, Tax Dollars are Spread Thin.

Sustainable Solutions

Be politically active, Vote with our wallets, Pursue quality of life, not just economic growth, Limit population growth, Encourage green tech, Mimic natural systems, Think globally, act locally, Think in the long term, Seek systemic solutions, Educate others.

Urban Ecology

Scientific field that views cities as ecosystems

Approaches for making cities livable and sustainable

Public Parks and Open Spaces, Greenbelts, Green buildings, Sustainable Energy in homes and businesses.