environmental science

h

Habitat destruction deforestation deprives species of their environment,

i

Invasive species,

lionfish in mediterranean

p

pollution-oil spill, agricultural runoff eutrophication too many nutrients in water

p

human population- more demand, burning fossil fuels

c

climate change-ice caps melting and polar bears nowhere to go

o

overharvesting, overhunting bison,

carbon cycle

The carbon cycle begins with photosynthetic organisms taking up carbon dioxide. This is called carbon fixation because carbon is changed from gaseous CO2 to an organic molecules like sugar. Sugar molecule is absorbed into the bloodstream of animals where it is made available to the cells for cellular respiration (energy release) or the production of more complex biomolecules.

Sustainability:

search for long term ecological stability and human progress.

Sustainable development:

meeting the needs of the present without compromising the ability of future generations to meet their own needs

examples

1. Combating poverty 2. Reducing resource consumption 3. Managing population growth 4. Universal access to healthcare 5. Sustainable cities 6. Environmental policy 7. Protection of the atmosphere 8. Combating deforestation and biodiversity loss 9. Combatting desertification and draught 10. Agriculture and rural development

steps of scientific inquiry

Identify question form testable hypothesis develop a test of the hypothesis collect data interpret results report for peer review

Systems Describe Interactions

System: network of interdependent components

and processes with materials and energy flowing

from one component of the system to another.

Ecosystem: complex assemblage of animals,

plants, and their environment, through which

materials and energy move.

Energy

is the ability to do work such as moving matter

over a distance or causing a heat transfer between two

objects at different temperatures.

Heat, light, electricity, and chemical energy are examples

that we all experience. Low quality from photosynthesis 10% used other becomes heat energy

thermodynamics

The study of thermodynamics deals with how energy is

transferred in natural processes.

• First law of thermodynamics: energy is conserved. It

is not destroyed during a process.

thermodynamics

Second law of thermodynamics: With each successive

energy transfer or transformation in a system, less

energy is available to do work. A lot of energy

degrades to low-quality energy.

The second law recognizes that disorder, or entropy,

tends to increase in all natural systems

energy for life

For nearly all life on earth, the sun is the ultimate energy

source.

This energy is captured by green plants which are often

called primary producers: They create carbohydrates and

other compounds using just sunlight, air, and water.

There are organisms that get energy in other ways. These

organisms gain their energy from chemosynthesis:

extraction of energy from inorganic chemical compounds

such as hydrogen sulfide (H2S).

Parasites, Scavengers, and Decomposers Are

Recyclers

Like omnivores, these recyclers feed on all trophic levels.

Scavengers, such as jackals and vultures, clean up dead

carcasses of larger animals.

Detritivores, such as ants and beetles, consume litter,

debris, and dung.

Decomposer organisms, such as fungi and bacteria,

complete the final breakdown and recycling of organic

Materials.

Biogeochemical Cycles and

Life Processes

The elements and compounds that sustain us are cycled

endlessly through living things and through the

environment (feedback loops).

On a global scale, this movement is referred to as

biogeochemical cycling.

carbon cycle

The carbon atoms from the sugar molecule could remain a

part of the animal’s body or the plant’s structure until it

decays after death.

Fungi and bacteria decompose the dead organic matter

and release carbon dioxide as a by-product of their

respiration.

Carbon Recycling may take a very long time.

Carbon in fossil fuels like coal and oil is not released until

the coal and oil are burned.

How humans disrupt normal cycling

burning fossil fuel co2 emissions taking from crust of earth, cutting deforestation, more carbon in atmosphere methane from cows, accelerating climate change

nitrogen cycle effect

Fertilizers using nitrogen not all taken by plants runoff from flood aquatic systems phytoplankton overgrowth consumers take in oxygen eutrophication decomp need a lot of oxygen other organisms suffocate, release nitrous oxide combine with water, acid rain

nitrogen cycle

Plants acquire nitrogen from nitrogen-fixing bacteria

that live in and around their roots. These bacteria

combine gaseous N2 with hydrogen to make ammonia

(NH3) and ammonium (NH . 4 ) +

Other bacteria then combine ammonia with oxygen

to form nitrites (NO . 2 ) −

A third group of bacteria converts nitrites to nitrates

(NO , 3 ) − which green plants can absorb and use.

Plant cells absorb nitrates, and use them to

build amino acids and eventually proteins

nitrogen cycle

Plant proteins are consumed by animals and

incorporated into their own protein molecules.

Nitrogen reenters the environment through the

death of organisms. Fungi and bacteria decompose

dead organisms, releasing ammonia and ammonium

ions for nitrate formation.

Denitrifying bacteria break down nitrates (NO3 ) − into

N2 and nitrous oxide (N2O), gases that return to the

atmosphere. Compete with plants.

nitrogen cycle

Nitrogen molecules (N2) are converted to useable forms in the

bumps (nodules) on the roots of this bean plant.

Each nodule is a mass of root tissue containing many bacteria

that help convert nitrogen in the soil to a form that the bean

plant can assimilate and use to manufacture amino acids.

phosphorus

The phosphorus cycle takes millions of years.

Minerals become available to organisms after they are

released from rocks or salts.

Producer organisms take in inorganic phosphorus,

incorporate it into organic molecules, and then pass it on

to consumers.

Excess phosphates in bodies of water can stimulate

explosive growth of algae, upsetting ecosystem stability.

Phosphorus

Minerals and crust, becomes exposed, release phosphorus back, geologic contains, over fertilize leach into aquatic systems Eutrophication decomposition of plankton

Nitrogen and phosphorus in waste

Terrestrial Biomes 1

Biomes: broad categories of living (eco)systems defined mainly by

climate (e.g., temperature/precipitation).

If we know the range of temperature and precipitation in a particular

place, we can predict the likely kind of biome of an area.

Biodiversity:

the number and variety of different biological species

that live in a biome.

Biodiversity also creates emergent properties

• Productivity

• Homeostasis

• Resilience

benefits of biodiversity

Even seemingly obscure and insignificant organisms can play

irreplaceable roles in their ecosystems.

• Ecosystem resilience

• Substances for drug development

• Gene identification

• Source of recreational activities

• Substrate for evolution

and evolutionary studies

Extinction

Studies of the fossil record suggest that >99 % of all

species that ever existed are now extinct.

Periodically, mass extinctions have wiped out vast

numbers of species.

Defaunation: Reduction of species abundance

Climate change

HIPPCO Summarizes Human Impacts

Between A.D. 1600 and 1850, human activities appear to

have eliminated two or three species per decade.

In the past 150 years the extinction rate has increased to

thousands per decade – ‘Sixth Mass Extinction’

Human threats to biodiversity summarized with the

acronym HIPPCO: Habitat destruction, Invasive species,

Pollution, Population of humans, Climate change and

Overharvesting

Habitat Destruction - Main Threat

The most important extinction threat for most species is

habitat loss.

Less than half of natural forests remain due to changes in

land use (cities, agriculture)

Habitat destruction also as a side effect of resource

extraction, such as mining, dam-building, and indiscriminate

fishing methods.

invasive species

lionfish in the mediterranean, Threaten native ecosystems

•Exacerbated by i) climate change; ii) Aswan Dam

Invasive Species Are a

Growing Threat

A major threat to native biodiversity is from accidentally or

deliberately introduced species.

Invasive species are organisms that thrive in new territory

where they are free of predators, diseases, or resource

population growth

In the past 40 years, the global population has

doubled from about 3.5 billion to about 7 billion.

Even if per capita consumption patterns remain

constant, more people will require more timber

harvesting, fishing, farmland, and extraction of fossil

fuels and minerals.

pollution

lead consumers consume others and die from poisoning, Toxic pollutants: disastrous effects on

local populations of organisms.

Bioaccumulation: accumulation of

toxic substances (DDT, PCBs, dioxins

and lead) from the environment in

the body of organisms.

Biomagnification: Higher-level

predators feed on many polluted

individuals, which increases pollutant

concentrations in their bodies.

Population declines are especially

likely in species high in the food

chain, such as marine mammals,

alligators, fish, and fish-eating birds

overharvesting

bison, Fish stocks have been seriously depleted. At least 3/4 of

all commercial oceanic species are overharvested.

• Eat sustainable varieties of fishes during the right

season, respecting size-related guidelines

• Eliminate harmful fishing practices that cause collateral

damage to ecosystems

keystone species

are those whose elimination would affect

many other members of the biological community.

Indicator species

Indicator species are those tied to specific biotic

communities, successional stages, or environmental

conditions.

Umbrella species

require large blocks of relatively

undisturbed habitat to maintain viable populations.

Flagship species

are especially interesting or attractive

organisms to which people react emotionally.