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46 terms

Ecology 6

a group of populations of different species living close enough to interact
___ boundaries are set by the researcher based on observed distributions;
observed patters, practical reality
most boundaries are easy to draw
natural edges
where abiotic factors change abruptly, sharp boundaries may exist between adjacent communities
natural edges
ex. river separates communities
came into focus in the 1970s
obligate (organisms can't live without each other) or facultative(can surivve without each other)?
ex. clown fish and anenome
clown fish are immune to poisonious anenome tentacles. if outside of the anemoe, clown fish gets preyed. anemone may use the food that the clown fish picks up
gut symbiosis
(mutualism) a whole range of organisms living in our guts; these organisms help you digest food. but may cause problems
(mutualism) obtains nectar, collects pollen and help the plant reproduction. however, the bee may cheat in this system because it can mate with an orchid
(mutualism) fungi gets into the cell wall of plants
nitrogen fixation
(mutualism) needs to be fixed by bacteria that lives in the plants
species diversity
includes species richness and species diversity
dominant species
a species that is numerically abundant (in individuals or biomass) and that forms a conspicous part of the community
dominant species
ex. American chestnut in American forests in the eastern side
keystone species
a species that is not necessarily abundant but that exerts strong control on community structure; puts community together
keystone species
ex. starfish for chitins, mussels, etc.
when keystone predator is absent, mussel population takes over
keystone species
ex. sea otters eats starfishs, mussels, etc
when you take the otters out of the system, urchin population booms- which removes the kelp forest
species cascade
ex. killer whales are starting to each sea otters (keystone species)
ecosystem engineers
ex. beavers physically modifies their shelthers
+ for other organsims, providing shelther for fish, ducks, etc
- for trees
facilitator species
positive effect on other species
the nonseasonal, direction, and continuous pattern of colonization and extinction on a site by species population
___ includes primary, secondary, and degradative
mechanisms include facilitation, inhabitation, tolerate
primary succession
when you start a clean, physical slate
primary succession
ex. after volcanic eruption- nothing survives. but organisms start to come back, starting brand new
secondary sucession
major distribuance: immediately after future, succession will start from a premade slate
trees and seeds and soil still intact
(succession) 1. first species to get there
(succession) 2. start to fix nitrogen (minerals for other organisms)
(succession) 3. better nitrogen fixers
(succession) 4. local climate, equlibrium system
r selected
come first, small reproductive
k selected
grow slowly, grow large, have long life span
life history strategy
r selected can eventually become k selected
r selected
many offsprings
r selected
offspring size small
r selected
maturation time short
r selected
young age at first reproduction
r selected
mortality rate high
r selected
short life span
r selected
no parental care
k selected
few number of offsprings
k selected
large offspring size
k selected
long maturation time
k selected
old age of first reproductio
k selected
low mortality rate
k selected
long life span
k selected
long parental care