EVR 2001 Exam 1

What is science?

Science is a body of knowledge and a method of acquiring further knowledge about the world around us.

How does the scientific method work?

Hypothesis-> Experiment(if possible)-> Observation and Measurement-> New/revised hypothesis-> Experiment(if possible)-> Observation and Measurement-> Substantiated Hypothesis

What is Environmental Science?

an interdisciplinary academic field that integrates physical and biological sciences (including physics, chemistry, biology, soil science, geology, climatology, and geography) to the study of the environment, and the solution of environmental problems.

Scales in Environmental Science

spatial, temporal, taxonomic

Major environmental issues

Biodiversity loss, habitat conversion and degradation, loss of ecosystem services, soil degradation, pollution, solid waste accumulation, eutrophication and dead zones, freshwater depletion, ocean acidification, anthropogenic climate change, and poverty, starvation, and inequality

What is sustainable development?

economic development that is conducted without depletion of natural resources

First Law of Thermodynamics

Energy (and therefore mass) can neither be created nor destroyed, just converted from one form to another

Second Law of Thermodynamics

With each conversion, energy loses some ability to do useful work

Entropy

A measure of the lost ability of energy to do work, or a measure of the decrease in order of a system

Convergent plate boundary

Occurs when oceanic and continental plates move together. The oceanic plate is forced under the lighter continental plate. Friction causes melting of the oceanic plate and may trigger earthquakes. Magma rises up through cracks and erupts onto the surface.

Divergent plate boundary

occurs when plates move apart. Volcanoes are formed as magma wells up to fill the gap, and eventually new crust is formed.

Conservative plate boundary (transform plate margin)

occurs where plates slide past each other in opposite directions, or in the same direction but at different speeds. Usually creates earthquakes

Energy from the sun

99.97% of Earth's energy budget

• Sunlight drives biological,

physical, and chemical processes

• Biological: Photosynthesis

• Physical: Atmospheric and ocean

circulation

• Chemical: Provides energy for some

reactions (e.g. giving you a sunburn,

formation of ozone)

Geological processes

take up (chemical weathering) and release (volcanism) carbon

• Many are very slow, but some are punctuated by sudden, dramatic events, like the formation of a new volcano or an earthquake

• Earthquakes can trigger tsunamis in the ocean and large lakes

• Landslides can reshape entire landscapes

• Floods are some of the most costly geological hazards

• Chemical weathering of limestone creates caves and sinkholes

Biogeochemical cycles

Complete path an element takes through the atmosphere, hydrosphere, lithosphere, & biosphere as it is converted from one form to others

Nitrogen cycle

Essential for synthesis of

proteins and DNA

1. Nitrogen fixation (N2 to NH3/ NH4+ or NO3-)

2. Nitrification (NH3 to NO3-)

3. Assimilation (Incorporation of NH3 and NO3- into biological tissues)

4. Ammonification (organic nitrogen compounds to NH3)

5. Denitrification(NO3- to N2)

Phosphorus cycle

• Essential for all life, often the limiting factor

for plant production

• Over time, rain and weathering cause rocks to release phosphate ions and other minerals. This inorganic phosphate is then distributed in soils and water.

•Plants take up inorganic phosphate from the soil. The plants may then be consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decays, and the organic phosphate is returned to the soil.

• Within the soil, organic forms of phosphate can be made available to plants by bacteria that break down organic matter to inorganic forms of phosphorus. This process is known as mineralization.

• Phosphorus in soil can end up in waterways and eventually oceans. Once there, it can be incorporated into sediments over time.

Carbon cycle

Carbon is an essential building

block of all life and the basis for

most complex molecules.

• Carbon enters the atmosphere as carbon dioxide from respiration (breathing) and combustion (burning).

• Carbon dioxide is absorbed by producers (life forms that make their own food e.g. plants) to make carbohydrates in photosynthesis . These producers then put off oxygen.

• Animals feed on the plants. Thus passing the carbon compounds along the food chain. Most of the carbon these animals consume however is exhaled as carbon dioxide. This is through the process of respiration. The animals and plants then eventually die.

• The dead organisms (dead animals and plants) are eaten by decomposers in the ground. The carbon that was in their bodies is then returned to the atmosphere as carbon dioxide. In some circumstances the process of decomposition is prevented. The decomposed plants and animals may then be available as fossil fuel in the future for combustion.

Human impacts on biogeochemical cycles

• Biogeochemical cycles are crucial to life

but are being greatly disturbed by human

activity.

• Most of the cycles are being accelerated,

causing both depletion of resources and

pollution

Haiti vs Japan Earthquakes

• High rates of poverty

• Lack of building codes

• Lack of consideration of scientific information in urban planning and development (construction in areas prone to flooding, landslides, etc.)

• Lack of disaster preparedness and post-disaster management despite long history of severe disasters

• Cleanup exceedingly slow (3 years to remove half of the debris), unacceptable conditions in refugee camps (no electricity and water), widespread violence, slow release of emergency funds for reconstruction.

• In Japan, debris was cleared within six months.

• Unlike Haiti, disaster relief was better organized in Japan and much quicker to reach affected people

• Lesson: Poverty, poor development planning, and poor governance make people more

vulnerable to natural disasters, and increase the severity of disaster impacts.

What is an ecosystem?

is the minimum level of ecological organization that has all the properties required to sustain life.

Population

Members of the same species living in the same area that can potentially breed

Community

Interacting populations of different species in the same area

Biomes

Large areas of the planet that are dominated by similar ecosystems

Biosphere

all life on Earth and associated habitats.

Species

a group of individuals that are genetically related and can breed to produce fertile young.

Levels of ecological organization

species, population, community, and ecosystem

Ecotones

transition areas between adjacent ecosystems

Closed communities

Sharp boundaries (edges)

Open boundaries

Indistinct/gradual boundaries

Habitat fragmentation

the complete process by which habitat loss results in the division of large, continuous habitats into a greater number of smaller patches of lower total area, isolated from each other by a matrix of dissimilar habitats, and is not just the pattern of spatial arrangement of remaining habitat.

Edge effects

diverse physical and biotic alterations associated with the artificial boundaries of fragments. Can have serious impacts on species diversity and composition, community dynamics, and ecosystem functioning

Ecosystem structure

the physical and biological makeup of the ecosystem

Environmental factors that determine where an organism can

live include:

• Climate

• Resource availability

• Interaction with other species

• Luck - individuals move to a new and suitable location by chance (e.g., organism moved to a different beach after a storm)

Ecosystem functions

Three levels of organisms regulate the flow of energy in ecosystems: the producers, the consumers, and the decomposers.

Ecosystem change

Natural or human-induced factors that directly or indirectly cause a change in an ecosystem are referred to as drivers.

• A direct driver, such as habitat change, explicitly influences ecosystem processes.

• An indirect driver, such as human population change, operates more diffusely, by altering one or more direct drivers.

Ecosystem services

are the subset of ecosystem functions which produce outputs that humans directly or indirectly derive a benefit from which include provisioning services such as food and water; regulating services such as flood and disease control; cultural services such as spiritual, recreational, and cultural benefits; and supporting services such as nutrient cycling that maintain the conditions for life on Earth.

Photosynthesis

the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

Light dependent reactions

use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage molecule ATP and the reduced electron carrier NADPH. In plants, the light reactions take place in the thylakoid membranes of organelles called chloroplasts.

Light independent reactions

are chemical reactions that convert carbon dioxide and other compounds into glucose. These reactions occur in the stroma, the fluid-filled area of a chloroplast outside of the thylakoid membranes. These reactions take the products (ATP and NADPH) of light-dependent reactions and perform further chemical processes on them. There are three phases to the light-independent reactions, collectively called the Calvin cycle: carbon fixation, reduction reactions, and ribulose 1,5-bisphosphate (RuBP) regeneration.

Respiration

is essentially the opposite of photosynthesis. Glucose and oxygen are used to produce energy, as well as carbon dioxide and water as wastes

Economic productivity

refers to the rate of generation of biomass in an ecosystem. It is usually expressed in units of mass per unit surface (or volume) per unit time, for instance grams per square metre per day (g m−2 d−1).

What are the general geospatial patterns?

a perceptual structure, placement, or arrangement of objects on Earth. It also includes the space in between those objects. Patterns may be recognized because of their arrangement; maybe in a line or by a clustering of points.

• Random distribution

• Clustered/clumped distribution

• Uniform distribution

Energy flows

Flow of biomass and energy through a simple food chain.

Primary producers (autotrophs) , primary consumers (herbivores), secondary consumers (carnivores), tertiary consumers (carnivores), and top predator

Habitat

the place or set of environmental conditions in which a particular organism lives

Eltonian niche

The organism's functional role (its response to and effects on its environment)

Hutchinsonian niche

Essentially the set of environmental conditions and interactions required to support a population within an environment

Competitive exclusion

• No two species can occupy the same ecological niche at the same time

• The one that is more efficient at using resources will eventually exclude the other

• Direct competition is very energy intensive, especially over long periods of time.

• In many cases, species get around competing directly by partitioning resources/niches amongst each other.

Resource partitioning

species can co-exist in a habitat by utilizing different parts of a single resource.

Example: swallows eat insects during the day and

bats eat insects at night.

Intraspecific competition

competition among members of the same species, which can be reduced by:

• dispersal of offspring

• exhibiting strong territoriality

• resource partitioning between generations

Interspecific competition

competition between members of different species. Species tend to avoid prolonged competition by resource partitioning

Predator

is any organism that feeds directly on another organism, whether or not this kills the prey.

True predator

kill their prey

Parasites

feed on an organism but do not immediately (or ever) kill it.

Herbivory

is the predation of plants by animals.

Mutualism

both organisms benefit from their association (e.g. corals and fish that eat algae that grow on the corals)

Commensalism

one species benefits while the other neither benefits nor is harmed (e.g. a bromeliad growing on the trunk of a tree absorbs water and nutrients dripping down the tree trunk without harming the tree).

Parasitism

a form of predation, is also sometimes considered a symbiotic relationship because of the prolonged dependency of the parasite on

its host.

Matter cycling

(the bio in biogeochemical cycles), including breakdown of wastes

Disturbances

is any force that disrupts established patterns

of species diversity and abundance, community structure, or community properties, e.g., storms, fires, logging.

• often disrupt the superior competitors the most and sometimes allows less competitive species to persist.

• Some landscapes never reach a climax community because they are characterized by periodic disturbances (such as

wildfires) and are made up of disturbance-adapted species.

• Many ecosystems are adapted to disturbances and require them to persist.

• Novel disturbances can result in catastrophic changes to the system

Succession

is the replacement of species in a community by

establishment of new species paralleled by replacement or extirpation of old ones.

• Pioneer species colonize a site that was opened by disturbance. These populations are replaced by intermediate sere species, which are eventually replaced by a climax community.

• Succession often makes an environment more suitable for life in general, deposits ecological memory

Primary succession

• A community begins to develop on a site previously unoccupied by living organisms.

• Example: A lava flow creates a new land area that is colonized. The first colonists are termed pioneer species.

Secondary succession

an existing community is disrupted and a new one subsequently develops at the site

Taxonomic classification

from most general to specific

• Domain (e.g. Eukaryota)

• Kingdom (e.g. Animalia)

• Phylum (e.g. Chordata)

• Class (e.g. Mammalia)

• Order (e.g. Primates)

• Family (e.g. Hominidae)

• Genus (e.g. Homo)

• Species (e.g. H. sapiens)

"Do Kings Play Chess On Fridays, Generally Speaking?"

How do organisms adapt to their environment?

Phenotypic plasticity

• Multiple phenotypes are possible for the same genotype

• Differences in gene expression in response to environmental stimuli

• Changes in phenotype may be permanent, especially when occurring during adolescence

• Important when environmental conditions change relatively rapidly

• Not passed on to offspring

Acclimation

• Getting used to environmental conditions through exposure

• A special type of phenotypic plasticity (short-term and reversible)

• Very limited and not passed on to future generations

• Examples: Sun tan, high altitude acclimation

Evolution

The change in heritable

characteristics of a population from

generation to generation through the

non-random survival of random

mutations

Four main processes

• Mutation

• Natural selection

• Geographic isolation and migration

• Genetic drift (reduces genetic diversity)

Mutation

• are the ultimate source for all genetic variation.

• Beneficial/deleterious mutations allow natural selection to play out.

• Most are neutral or detrimental.

• Beneficial mutations are random and rare.

Natural Selection

acts as a "screening mechanism" for mutations, favoring those that are advantageous to the local

environment.

1. Requires initial variability within population

• Non-neutral mutations are a prerequisite for natural selection to play out.

2. Requires environmental variability within range

3. Differential reproduction and survival that varies with environmental conditions

>> Selection for beneficial traits

• The most-fit (best-adapted) organisms tend to survive for longer and have more viable offspring, so their DNA is passed on more frequently than that of organisms that are not as well adapted.

Geographic isolation

Isolated populations can no longer interbreed (no gene flow). Their evolutionary trajectory is more likely to deviate.

Types of Diversity

Biodiversity is "the variety and variability among

living organisms and the ecological complexes in

which they occur." It can be quantified in many

different ways:

• Genetic diversity- within-species diversity as measured by DNA

• Species diversity- species richness (# of species), species evenness, species dominance

• Ecological diversity- diversity of habitats, niches, and ecological processes

Simpson's Index

used to calculate species diversity

Biodiversity hotspots

• Conservation priorities

• Regions that contain a disproportionate share of biodiversity, high in endemic species

• In danger of degradation

• Not to be confused with geological hot spots

• Usually found near the equator

Cambrian explosion

refers to the sudden appearance in the fossil record of complex animals with mineralized skeletal remains. It may represent the most important evolutionary event in the history of life on Earth.

Mass extinctions

When a large group of species becomes extinct normally do to a catastrophe

HIPPO

Habitat loss, invasive species, pollution, human population, and over harvesting

Species level conservation

Sanctions

• Regulations only effective if enforced

Providing alternative livelihoods

• Encouraging poachers to become involved with wildlife conservation

Captive breeding

• Protecting rare populations from natural hazards by removing them from their environment

• Increase population numbers through breeding (often "assisted"), followed by re-release into the wild

Landscape level conservation

• Focus on ecosystem functions and services over individual species

• Recognition that species cannot exist in isolation

• Sometimes established by land-for-debt swaps (controversial)

• Tends to allow for more flexibility to incorporate needs of local people

• Shade-grown coffee

• Sustainable grazing

• Extraction of non-timber forest products

• Conservation of cultural assets: Traditional land uses and skills, native languages, etc. which connect people to the land they inhabit ("Living History Museums")

Essential aspects:

• Enforcement of regulations

• Good relations with local people

• Learning from indigenous and rural people to complement academic knowledge

Many different types of protected areas exist.

• Various degrees of human activities permitted

• Some try to concentrate human activities in fringe areas, leaving core habitat less affected

• Bias toward mountains and deserts in U.S.

• Most forests and grasslands are managed for human use (National Forests, National Grasslands)

• Increasing importance of private protected areas

Matrix

• Incentives for private landowners to manage their land in certain ways (including conservation easements)

• Land purchases by trusts to establish new protected areas or expand existing ones

• Conservation corridors to link them

Exponential growth

While resources are abundant and competition/predation is low, growth is limited only by biotic potential.

• Nt = N0×ert

• N = population size, t = time, r = growth rate

Logistic growth

More typically, growth begins to slow as a species nears K because density dependent limits to growth increase:

• Increased stress and intraspecific

competition for resources

• Increased likelihood of disease

transmission

• Increased susceptibility to predation

• Result: increased mortality,

decreased reproduction, and/or

increased emigration.

r

strength in numbers

K

strength through parental care and protection

Metapopulations

Although the dynamics and evolution of a single closed population are governed by its life history, populations of many species are not completely isolated and are connected by the movement of individuals (immigration and emigration) among them.

Dawn of our species

• Homo sapiens sapiens developed from archaic

humans about 200,000 years ago

• Originated in Sub-Saharan Africa

• Reached near-globalextent by 10,000 years ago

I=PAT

The environmental impact of the human population is correlated with its size (P), its affluence or level of consumption of resources per person (A), and the technologies used to access and process those resources (Tx)

Pattern of human population

U.S. net gain of 1 person every 17 seconds.

World net gain of 8800 people every hour!

(146 people/minute)

The world's population has doubled since 1970

Key principles in demography

• Life expectancy

• Crude birth rate

• Crude death rate

• Growth rate

• Total fertility rate

• Replacement fertility rate

• Doubling time

• Demographic momentum

Current trends in population growth

Demographic Trends

• The growth rate of the world's population has roughly halved since the 1960s

• Mid-century population projections have been increasing

• Declining healthy sperm counts

• Increasing number of serious disease outbreaks

Problems with shrinking populations

"Aging" of the population

• Changing dependency ratio

• Ratio between non-working and working age population

• Migration to developed countries tends to offset this problem slightly

• Shift from needing to provide child care and education to social security and welfare for the elderly

• Declining economic output

• Need to increase worker productivity

Fundamentals of energy

Energy is the ability to do work

• Radiant - energy contained in electromagnetic radiation, e.g. solar radiation

• Chemical - energy stored in molecular bonds. Photosynthesis converts radiant energy into chemical energy.

• Kinetic - energy of motion. Wind, for example, is solar energy converted into moving air.

• Potential - energy of position. Can be converted into kinetic energy by allowing the object/substance to roll/flow/fall to a lower elevation.

• Mechanical - the sum of kinetic and potential energy

Energy quality - how easy it is to capture and use various types of energy sources. Relates to energy density (amount of energy per unit volume).

Energy vs Power

What is it?

Energy- Ability to do work (an amount)

Power- Rate at which energy is consumed or produced

Abbreviation

Energy- W orE

Power- P

SI Unit

Energy- Joule (J)

Power- Watt (W) = 1 Joule/second

Other Common Units

Energy- calorie (4.2 J), kcal (4.2 kJ) (dietary Calorie), BTU (1055 J), and kWh (3.6 MJ)

Power- Horsepower (735.5 W)

Different energy sources

Coal, petroleum, natural gas, and nuclear fuels