Ecology Lecture 7 Flashcards
Define: COMMUNITY
a COLLECTION OF SPECIES (each with its own population) living in a PARTICULAR AREA at point in time
Define: SUCCESSION
the PROCESS by which the MIX of species and habitat CHANGES over TIME
Define: PIONEER SPECIES
the FIRST species to arrive in a BARREN or UNDISTURBED area
Define: EXTIRPATION
the LOCAL EXTINCTION of a species from a particular area
Define: INTERMEDIATE SPECIES
species which appear AFTER the PIONEER species have established themselves but BEFORE the CLIMAX COMMUNITY
Define: CLIMAX COMMUNITY
a STABLE community that has reached a relatively STEADY STATE through ECOLOGICAL SUCCESSION
What drives succession?
DISPERSAL and COMPETITION
How do organisms budget their energy?
FINITE amount of energy that must be allocated to growth, maintenance, activity, and reproduction
more energy for growth = less energy for reproduction
List traits of PIONEER SPECIES
high dispersal
short lifespan
lots of offsprings
rapid growth
able to tolerate harsh soil conditions
poor competitors
list traits of INTERMEDIATE SPECIES
require some soil nutrients
moderate dispersal
grow moderately fast and high
contribute to building new soil
List traits of CLIMAX SPECIES
long lifespan
fewer offsprings
slow growth
good competitors
low dispersal rates
unable to tolerate harsh conditions
more shade tolerant (shade appears after climax species)
where does PRIMARY SUCCESSION occur?
NEWLY formed, previously UNINHABITED area, with NO SOIL (eg. volcano, glacial retreat)
where does SECONDARY SUCCESSION occur?
an area that has been DISTURBED but still has a SOIL LAYER and ORGANIC matter (Eg. wildfire, hurricane, logging)
Define: DISTURBANCE
any PHYSICAL or ENVIRONMENTAL EVENT that disturbs the STRUCTURE or FUNCTION of an ecosystem
Define: INTERMEDIATE DISTURBANCE HYPOTHESIS
the HIGHEST SPECIES RICHNESS will occur at an INTERMEDIATE level of frequency and intensity of DISTURBANCE, as this creates NEW HABITATS without causing extinction
leads to MORE NICHES
