Chapters 24 And 25 Flashcards
The levels of organization
Atom Molecular level
Molecular level
Organelle level
Cellular level
Tissue level
Organ level
Systemic level
Organism level
Levels of organization for ecology
Species
Population
Community
Ecosystem
Biosphere
Biosphere
- all the ecosystems on Earth
- “portion of the Earth that contains living organisms”
Ecosystem
- a community or organisms and the physical environment in which they live
- “specific areas of the biosphere where organisms interact”
Biomes
- major types of terrestrial ecosystems
- Defined by climate conditions
Biotic components of an ecosystem
- ecosystem includes both living and non living components
- Biomass: total living component of an ecosystem
- nonliving components include: chemical elements; an essential constant supply of energy
- biotic components are categorized by how they obtain their energy
Energy low through ecosystems obeys the laws of thermodynamics
- first law of thermodynamics: energy is neither created nor destroyed; energy can change form
- second law of thermodynamics: some energy is wasted when it changes form or is transferred; energy is usually converted to heat
Producers
- capture and convert energy
- make their won organic molecules
- i.e., they produce food
Consumers
- acquire organic molecules and energy by consuming other organisms
I.e., they consume food
Energy flow
- sun -> producers -> consumers
Producers -> autotrophs
- “self-nutritive” or “self-growing”
- most producers are capable of photosynthesis
- terrestrial ecosystems: plants
- aquatic ecosystems: algae - equation for photosynthesis:
CO2 + H2O -> C6H12O6 + O2 = Glucose - some autotrophs are capable of chemosynthesis
Consumers -> heterotrophs
- most consume foods that already contain stored forms of energy
- Herbivores: primary consumers; use green plants as an energy source
- Carnivores: secondary or tertiary consumers; use other animals as energy source
- Omnivores: use either plants or animals as energy source
- Decomposers: use dead organisms as energy source
Niche
- the role of an organism in an ecosystem
(producer vs. Omnivore) - How an organism: gets food, interacts with other populations, physical habitat
- well-balanced ecosystem supports a wider variety of species, each with a different niche
- niches may overlap, resulting in competition between species for limited resources
How is energy flow depicting
- energy flow is often depicted as a chain of events
I.e., food chain; however, this (much like the scientific process) is a “watered down” example
- similar to the scientific method vs. the scientific process
Food web
- a diagram describing trophic, or feeding relationship
- grazing food web
- detrital food web
Habitat
- location where a species lives
- has certain chemical and physical characteristics favorable to the organism’s comfort and survival
Geographic range
- the area over which a species is found
- limitations: competition for resources, intolerable conditions, physical obstacles
The lower levels of an ecological pyramid support consumers populations
- depict total biomass or total energy stored at each level of an ecosystem
- producers capture approximately 2% of the energy in sunlight
- only about 10% of the energy from a lower level is available to the next higher level
- lower level of ecological pyramid support consumer populations
- consumers at any level depend critically on the populations of consumers directly below it
- small amounts of energy available to tertiary consumers depends on energy transfers at all levels below them
Human activities that disrupt ecological pyramids
- humans as primary consumers (eating plants)
- humans as secondary consumers (eating meat; utilizing only 10% of energy that would be available from plants)
- modern farming practices exclude other species or heir place in the food web and their ecological pyramid
Biogeochemical cycles
- includes living organisms, geologic events, weather events: water cycle, carbon cycle, nitrogen cycle, phosphorus cycle
- molecules and element cycle between three different pools:
- biomass: (living organisms)
- exchange pool: (water, soil, atmosphere)
- reserve: large, but hard-to-access pool of nutrients
The water cycle
Evaporation
Condensation
Precipitation
Runoff/aquifers
Human activities that effect the water cycle
- withdraw from aquifers
- deforestation/clearing vegetation = increase runoff
- interfere with the natural processes that purify water
- add pollutant to water sources
The nitrogen cycle
- occurs when nitrogen gas is converted to ammonium, a form that plants can use
- Nitrogen: essential component of proteins and amino acids - atmosphere: largest reservoir of nitrogen
- Nitrogen fixation: converts atmospheric nitrogen to ammonium
- Legumes: (peas, alfalfa, soybeans) - nitrification: converts ammonium to nitrate
- denitrification: converts nitrates back to nitrogen gas (N2)
Human activities that effect the nitrogen cycle
- double the fixation rate by fertilizing crops
- air pollution cause tissue damage in lungs
- acid deposition
- soil acidification
- ozone depletion
Phosphorus: A sedimentary cycle
- phosphorus never enters the atmosphere
- human activities disrupts the balance of this cycle
- creates increased runoff of phosphorus into aquatic ecosystems
- runoff may cause excessive algal growth (blooms)
- decomposers feeding on dead algae may take up so much oxygen for metabolism that other organisms may suffocate (eutrophication)
- human activities disrupts the balance of this cycle
Humans impact on the natural biogeochemical cycles
- impacts:
Energy flow
Food web
Ecosystems
Biosphere
Human health
Carrying capacity
The maximum population the environment can support for an extended period of time
Biotic potential
- the maximum rate of growth of a population under ideal conditions
- determined by: # of offspring produced by each member, length of time for individuals to reach reproductive maturity, ratio of males to females, # of reproductive-age individuals
Population growth rate trends toward biotic potential
- the world’s population has Been steadily growing to a present size of slightly over 7.6 billion people
- experiencing exponential growth
Human population growth
- most of human history
- stable population, never exceeding 10 million people until about 4,000 years ago
- 4,000 years ago
- began slow increase in human population
- development of agriculture decreased environmental resistance and increased carrying capacity
- 300 years ago
- Industrial Revolution
- rapid growth in human population
Factors that reduced environmental distance and/or increased biotic potential
- agricultural development
- plant and animal domestication - improved medical care
- vaccines
- antibiotics
- improved transportation
- improved housing
- advances in communication
Growth rate =
Fertility rate =
Growth rate = births/year - deaths/year
- current human population growth rate = 1.1%
- to reach zero population growth, we must decrease the birth rate
Fertility rate = number of children/woman
Replacement fertility rate
Replacement fertility rate = 2.1 children/ woman
- even of fertility at which a population exactly replaces itself (generation to generation)
- if replacement fertility rate is achieved by 20205, population would stabilize at about 9.6 billion
- estimate range from 8.3 to 10.9 billion
- the difference in these estimates is only one child per couple
Age structure
Number of people in each age group within a population
Demographic transition
Progressive changes in the age structure of a population
- this occurs as a country undergoes industrial and economic development
more industrialized countries (MICs)
- Europe, North America, Australia, Japan
- roughly the same number of people are in pre-productive, reproductive, and post reproductive groups
- predicts a more stable population
Less industrialized countries (LICs)
- Africa, Latin America, Asia
- pyramid shape of age structure
- much of population is younger than reproductive age
- predicts a population continuing to expand
Age structure: predictions
over the next 50 years, population growth will be most rapid in the less industrialized countries, the countries least able to provide for their citizens
Environmental resistance
Environmental resistance: factors that kill organisms or keep them from reproducing
- limitations on nutrients, energy, space
- predation by other species
- disease
- environmental toxins
no population grows at its full biotic potential indefinitely
carrying capacity
- population size that the environment can support indefinitely
concerning of a growing population
pollution
water
food
energy sources
land
climate change
-
pollution
- Major concerns regarding air pollution:
- global warming
- destruction of the ozone layer
- acid precipitation
- smog production
pollution: Global warming
- Greenhouse effect: gasses let sunlight through, but trap heat from radiating back outward into space
- Carbon Dioxide (CO2), Methane (CH4), Nitrous oxide (N2O)
-> greenhouse effect responsible fore: global warming
- Carbon Dioxide (CO2), Methane (CH4), Nitrous oxide (N2O)
human activities have increased levels of CO2, a major greenhouse gas, through?
- deforestation
- burning of fossil fuels
pollution: acid precipitation
- sulfur dioxide from high-sulfur coal and oil
- nitrogen oxides from car exhaust
- sulfur dioxide +nitrogen oxide = sulfuric acid + nitric acid
- acid precipitation damage includes: corrosion of metal and stone; disruption of forest and aquatic ecosystems
- in North America, the northeastern united states and parts of Canada have been the most affected
- acid precipitation is decreasing due to pollution abatement measures
pollution: Smog
- Smoke + fog = smog
- components of smog include: nitrogen oxides, hydrocarbons, eye and respiratory irritants, small oil droplets; wood particles; coal ash; lead; animal waste; dust
- Major source: burning fossil fuels
- Thermal inversion: atmospheric conditions that trap smog and prevent its dispersal
- Control: air pollution abatement measures
human activities have three major detrimental effects on water quality and availability:
1) Humans use excessive water, depleting fresh water supplies
2) building roads/parking lots prevents rainwater from soaking in, causing runoff
3) human activities pollute water sources
water is scarce and unequally distributed
- Distribution of Earth’s Water: fresh water is <1%, salt water is 97%, glaciers/polar ice caps are 2%
- industrialized countries use 10 to 100 times more water than less industrialized countries
- some desert and semiarid countries have reached carrying capacity regarding water supplies
- Diversion of water impacts other human populations and other species
urbanization increases storm water runoff
- combined sewage overflow (CSO) created
- storm water combined with sewage - CSO overwhelms receiving streams and oceans
- human disease spread by CSO-carried pathogens: gastroenteritis, ear and eye infections, skin infections, respiratory infections
- leads to stream erosion
human activities pollute freshwater
- organic pollutants -> from sewage and industry
- inorganic pollutants -> nitrates, phosphate fertilizers, and sulfates from detergents
- may result in eutrophication
Eutrophication resulted from human activities that pollute freshwater
- in a shallow body of water, rapid growth of plant life leads to death of animal life resulting from excessive organic or inorganic nutrients
human activities pollute freshwater
- toxic pollutants: polychlorinated biphenyls (PBCs), oil and gasoline, pesticides, herbicides, heavy metals
biological magnification
the concentration of toxic pollutants is higher in the tissues of organisms higher on the food chain
- Example: accumulation of mercury in fish
oil pollution and garbage are damaging oceans and shorelines
- garbage, primarily plastics
- degrades very slowly
- floating garbage ends up on the shorelines or in big floating “rafts” in the open ocean
- Example: Pacific
Trash Vortex
how pollution and overuse damage the land
- 1/3 of Earth’s landmass has been altered by human activity
- 50% of forests have been removed
- migration to cities: footprint of cities expands, consuming productive land and increasing water runoff issues
Desertification
transformation of marginal land into near-desert conditions, unsuitable for future agriculture
- wars
- garbage disposal
Energy: many options, many choices
- nonrenewable resources: fossil fuels (coal, oil, gas)
- renewable energy sources: (Nuclear energy: safety, disposal issues; biomass fuels (biofuels);)
- use of plant materials for fuels
- land use issues (food or fuel?) - hydroelectric power, wind farms, geothermal energy, solar power
Environmental change and loss of biodiversity
- biodiversity: species richness, the assortment of living organisms on Earth
- currently, scientists have identified 1.75 million different species
- estimates of 10-30 million or more different species
- biodiversity represents the variety of all forms of life
- human activities have reduced biodiversity worldwide
humans alter and destroy habitats
- pollution
- overexploitation of natural resources
- farming
- overfishing
- exploitation of scarce forest resources
- logging
- deforestation
towards sustainable development
- development that meets the needs of the present without compromising the ability of future generations to meet their economic needs
Gross Domestic Product (GDP)
- total market value of all goods and services produced within a country per year
- standard indicator of economic progress
Genuine Progress Indicator (GPI)
- market value of goods and services PLUS
- environmental costs of products of goods and services
- social costs
- quality of life
strategies to support sustainable development
- consume less
- recycle more
- support sustainable agriculture
- support green roofs
- lower worldwide fertility rate
- reduce rural world poverty
- conserve energy at home
- use environmentally preferable products
- protect ecosystems that provide ecoservices
