Ch. 2 – The Living World

Ecosystems
made of all the living/unliving components interacting in a specific area at the same time
population
group of individuals of same species in an area at the same time
community
multiple populations of dif species in a given area
habitat
animal’s living area; inc, soil, vegetation, water supply, & other factors
keystone species
species w/ dramatic impact on ecosystem they live in (i.e. beavers, sea otters, wolves, elephants)
niche
organism’s place in the community; habitat use, food consumption, species interactions, shelter
generalists
have ability to survive in dif environments/situations
specialists
adapted to specific environment; vulnerable to change
competition
fighting over the same resources; one has to beat the other; can be between 2+ dif species or same species
mutualistic interactions
benefiting from one another; no one is harmed in the making of ___; i.e. bees & flowers;
predation (predator/prey relationship)
eating another species; one benefits, other dies; related to transferring of energy thru trophic levels
parasitism
organism uses another for food & nutrients without immediately killing it; often the two species evolve relative to each other
herbivory
eating plants; plants hurt but animals benefit; plants develop thorns, toxins, hairs to discourage eating
commensalism
one species benefits, the other doesn’t care
amensalistic relationships
one organism harms/inhibits another for no reason/doesn’t benefit
biomes
large ecological areas dominated by particular plant type
aquatic biomes
categorized by categories such as salinity, temp, nutrients, currents, depth, wave action, animals, and bottom substrate
Tropical Rain Forest
high yr-round percipitation; warm yr-round; high biodiversity; around equator; acidic soil bc most nutrients within vegetation
Tropical Dry Forest
low overall rain, but rainy half yr; warm yr-round; adapted to seasonal fluctations; India, Africa, S. America, N. Australia
Temperate Rain Forest
High rainfall yr-round; moderate rainfall; coniferous trees, mosses, moisture-loving species; Pacific NW (US) & Japan
Temperate Deciduous Forest
Rainfall even throughout yr; seasonal temps; deciduous broadleaf trees; Europe, E NA, eastern China; fertile soil
Boreal Forest/Taiga
long winters, short cool summers; moderate rainfall; evergreen forests, moose, lynx; Canada, Russia; many bogs, lakes & poor nutrients in soil
Savanna
Short rainy season; warm/little seasonal variation; grasslands w/ acacias, zebras, lions; Africa, S America, Australia, India
Chaparral
seasonal w/ wet winters & dry summers; mild winters & warm summers; evergreen shrubs; CA, Chile, S Aussie, land around Mediterranean Sea; freq. fires
Temperate Grassland/Steppe
Low precip.; extremely seasonal; mainly grasses; bison, prarie dogs; N/S America, central Asia; cleared for agriculture
Tundra
low rainfall; cold winters, cool summers; lichens, low vegatation, migratory animals; Artic Russia, Scandinavia, Rockies; short winter days/long summer days; soil permanently frozen
Desert
minimal rainfall; temps vary dramatically day/night; some bare/no vegetation, kanagroos, rattlesnakes; Africa, AZ & NW Mexico; soil has high saline content
Photosynthesis
getting energy from sun; key for all animal’s survival (except for chemosynthetic organisms); 6CO2+6H2O+light-> C6H12O6+6O2
Chemical Respiration
process of “burning” carb glucose in presence of O for energy
food webs
models of overlapping food chains; represents complex flow from producers to consumers to decomposers in an ecosystem
food chain
simple layer of energy flow from producer to various consumers
autotrophs
producers; convert sunlight to energy
consumer
herbivores (primary consumers); omnivores (primary/secondary/teriary consumer); carnivore (secondary/tertiary); convert stored energy in plants; ocean producers might have less producers, but otherwise normal dist.
ecological pyramid
diagram that shows loss of energy in each level trophic level
trophic level
layer that an organism occupies (consumer/producer/decomposer); 90% of energy lost through transfer of this
ecosystem diversity
variety of ecosystems in specific area; low: large prarie land; high: forest w/ dif tree species
species diversity
number/variety of a species within a community
species richness
number of species in an area
relative abundance
number of each species in comparison to the others
genetic diversity
variation of heritable DNA amongst a species’ individuals
biodiversity
total of all species in a given area at a specific time; viewed by ecosystems, species, genetics; not evenly distr. bc of factors like climate/altitude/topography
latitudinal gradient
the higher the latitude, the less animals living in areas
evolution
variation in genetic makeup of population of organisms through generations; takes place over many gens, randomly or nat’l seletion
Natural Selection
genetic traits strengthen an organism’s chance of survival & reproduction are passed on to future gens
adaptive traits
successful evolutions
mutations
accidental evolution; may or may not be successful (i.e. albinoism – not; humans walking – did)
artificial selection
humans impact which traits are selected; dog/cat/horse/cow/pig/etc breeds
stabilizing selection
characteristics are moderate and either side of characteristic is deadly (beak too long/short to reach pollen)
Disruptive selection
discriminates against individuals w/ characteristics at extremes; evolution occurs with either extreme dominating population (long or short beaks, but no medium)
directional selection
favors one extreme, so the other extreme/average fade away
sympatric speciation
similar organisms live in the same place, but have different jobs
allopatric speciation
species seperated physically and evolve differently
ecosystem services
what an ecosystem does to support life on Earth
extinction
everyone dies
extiration
everyone dies – but only in one place
Endangered Species Act (ESA)
keeps US gov’t/private citizens from doing anything to affect endangered species & their habitat
Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)
bans transportation of endangered species’ body parts internationally
background extinction rate
everyone dies, but gradually over time
mass extinction rate
everyone dies at practically the same time; 5 known events
primary ecological succession
starts with bare rock w/ no soil or life
secondary ecological succession
re-growth of an area after an event has wiped out prior community; still soil and life
pioneer species
organisms that start ecological succession
biogeochemical cycles
movement of nutrients through ecosystems
reservoir/sink
nutrient storage
carbon
exists in living organisms, decomposing components of ecosystems, abiotic environmental factors; soluble in water
carbon cycle
moves through animals when they consume organisms; released into atmos during cellular respiration & decomposition
carbon reservoirs
plants, oceans, sedimentary deposits (carbonate rocks); coal, gas, crude oil
oxygen cycle
aids in formation of atmos’s ozone; oxidizes rocks and minerals so they aren’t in atmos; photosynthesis
nitrogen cycle
starts as a gas; fixed to soil by lightning or bacteria; creates ammonia (becomes ammonium, water-soluble ion), sometimes further converted by other bacteria to convert into __O3; taken in by plants; decomposers process it and return it to soil; de____ return it to air
“fixing” nitrogen
lightning or nitrogen-fixing bacteria; bacteria live in soil and in nodules on roots of legumes
nitrification
converting ammonium to nitrite (NO2-) ions then nitrate ions (NO3-) by nitrifying bacteria
Haber-Bosch process
nitrogen fixation process created by humans; has negatively altered nitrogen cycle by doubling amt of nitrogen fixation occuring on Earth, which can lead to eutrophication
phosphorous cycle
found in soil, rock, sediments; released from rocks through chemical weathering; absorbed from soil into plants; limiting factor for plant growth; can enter water table & create dead zones
sulfur cycle
released into atmos from rocks thru weathering, volcanic eruptions, and decay of dead organism; reacts w/ oxygen and water; deposited back into soil & water or combines with water and becomes acid rain; absorbed by plants