ENVS 1000

limiting factors
A limiting element is the element that is in the shortest supply for plant growth and therefore the one that, if added, will result in the largest increases in growth.
biological invasion
when a non native species enters an ecosystem and puts native species in danger of being threatened or endangered.
First Law of Thermodynamics
energy is neither created nor destroyed
second law of thermodynamics
With each successive energy transfer, less energy is available to perform work
Genetic Diversity
Measures variety of different versions of same genes
Species Diversity
Measures number of different kinds of organisms within a community
Ecological Diversity
Measures richness and complexity of a community
Species Richness
Total number of species in a community
Species Evenness
Relative abundance of individuals within each species
biodiversity hotspots
areas with a large amount of ecological diversity with species endemic to the area
reproductive isolation
genetic species concept
evolutionary species concept
number of species
currently 1.5 million known
70% of these are invertebrates
majority of species are insects
extinction due to natural causes
in undisturbed ecosystems rate appears to be 1 extinct species every 10 years
extinction due to humans
humans causing 6th mass extinction
extinction rate has increased by a factor of 1000
over 1000 species extinct in past 1000 years
habitat alteration
endangering a species by altering their natural habitat by direct influence (agriculture in amazon) or indirect causes (pollution of stream caused by chemicals)
invasive species
non native species are introduced into an ecosystem where they thrive and put native species at risk of becoming endangered due to competition of resources/predation
hazardous materials mess up the ecosystems, causing native organisms to suffer (exxon oil spill, DDT and bald eagles)
population growth
increased number of people increases stress on ecosystems and their residents
over-harvesting of species from wild
over consumption of resources
mass extinctions
causes mostly unknown
loss of over 50 % of species from earth
benefits of bio diversity:
lots of edible plants and animals
benefits of bio diversity:
drugs and medicine
lots of ingredients for drugs found in wild
benefits of bio diversity:
aesthetics and cultural benefits
cultural diversity linked to bio diversity
intrinsic value
benefits of bio diversity:
economic benefits
lots of money spent on natural activities each year
benefits of bio diversity:
ecological benefits
soil formation, pollination, air/water purification and more all depend on bio diversity
endangered species act:
species focused
high impact small focus
endangered- species may go extinct
threatened- less urgent than endangered
candidate- not enough money among gov, to protect
National environmental protection agency
low impact large focus
3 part process focused
environmental assessment
environmental impact focus
population control
if we dont do it lowered birth rate of increase in death rate will do it for us
resources are finite
conventional agr
synthetic inputs
GMO revolution
alternative/sustainable agr
managing multiple services
biological methods of farming (natural fertilizers)
BT toxin
natural pesticide produced by some plants
GMO pros
higher yields
reduce fertilizer use
increase of nutrient content
drought resistant
GMO cons
companies ‘own’ living organism
farmers have limited access to seeds
pests adapt to new plants
more resistant
transgenetic organism
any organism that has genes moved around with modern technology
Evolution necessities
different traits must be present in population
traits must affect reproductive success
traits must be inheritable
some selective pressure must favor traits
good in short term bad in long term
diseases build tolerance to them
land use
high majority of productive land in use at the moment
erosion a natural process and makes riverbanks fertile
bad when it washes topsoil away to sea.
wind erosion
problem in dry areas
recovery plan
plan that details steps to get species of endangered list
food supply
food abundance not a problem, poverty is
land degradation
many acres of land rendered unusable per year
water degradation biggest cause of this
leaches soil of nutrients
malthusian growth
population increase exponentially while food is abundant and declines when food runs out
karl marx
population growth a result of poverty and other social problems
social justice = population control
more people = more solutions to out problems
stupid idea
poor and young
rapidly growing in under developed countries
80% of world population and 90% of growth
old, wealthy and shrinking
average age is 40
premodern society demographics
death rate high and birth rates high
keystone species
species that has a greater impact on its environment than most others (bees, humans)
interspecific competition
between members of different species
intraspecific competition
between members of the same species
organisms that feed directly on other living organisms
intimate living together of two or more species
one member benifits
both members benefit
one member benefits at expense of other
growth rate
how many children born
age of parent when they give birth
death rate
immigration (into country)
emmigration (out of country)
age structure
distribution of age groups within a culture
crude birth rate
total number of births per thousand
total fertility rate
number of children born per average woman in population
crude death rate
number of deaths per thousand
zero population growth
birth rate + immigration rate = death rate + emigration rate
natural increase in population
birth rate and death rate
total growth rate
emigration and immigration in addition to natural growth rate
dependency ratio
number of independent individuals verse dependent individuals in a population
demographic transition
death rates and birth rates start out high
conditions improve and death rates fall, birth rates remain same or grow
eventually birth rates fall
population grows rapidly in between death rate and birth rate fall
population has low death and birth rates and numbers reach equilibrium
HIV/AIDS and population growth
AIDS have caused negative population growth in south africa
instability in age structure and
ecological footprint
amount of land required to produce raw materials for consumption and house waste
primary succession
A community begins to develop on a site previously unoccupied by living organisms
secondary succession
An existing community is disrupted and a new one subsequently develops at the site
large-scale food shortages, massive starvation, social disruption, and economic chaos
can be environmentally caused
most often caused by political situations and economics
“displaced child” occurs in children whos diets lack protein
characterized by reddish hair and bloated bellies
“to waste away” starvation caused by insufficient proteins and calories
three biggest crops
corn, wheat and rice