Population Dynamics Flashcards
(26 cards)
Abundance
the number of individuals in a population
Density
the population size per unit area
Metapopulation
populations of populations, some of which go extinct and later become recolonized
source/sink habitats
Emigration
departure of individuals from a population
Immigration
arrival of individuals from a population
Exponential growth
when population increases by a fixed % each year
E.g. When colonizing an unoccupied environment or exploiting an unused resource
Populations become constrained eventually due to limiting factors
Logistic growth
when populations show initial exponential growth which stabilizes as limiting factors increase or resources decrease
Carrying capacity (K)
the maximum population that can be sustained by a specific environment
Life History
the sequence of events related to survival and reproduction that occur from births through death
r selection
species whose life history strategy allows for a high intrinsic rate of population increase (r)
K selection
species whose life history strategy allows it to persist at or near the carrying capacity (K) of its environment
Community Ecology
examines how interactions among species and their environment affect the abundance, distribution and diversity of species within communities
Community Ecology has two important conceptual models:
Trophic levels
Food webs
Autotroph
(primary producer)- an organism that produces complex organic compounds from simple substances present in its surroundings
e.g. plants convert inorganic CO2 into glucose (w/ photosynthesis)
Heterotroph
(consumers)- an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon
e.g. animals consume plants and other animals
Decomposers
Microbes and fungi that break down dead organic matter
External digestion
Detritivores & Scavengers
Animals that consume dead organic matter (leaves, carrion, waste, etc.)
Internal digestion
Food Webs
Map trophic levels and interactions of an ecosystem
Trophic Cascade
The wolves in Yellowstone
Ecosystem engineers
organism that creates, significantly modifies, maintains or destroys a habitat. Examples?
e.g. prairie dogs, coral, mollusks, beavers, etc.
These organisms can have a large impact on the species richness and landscape-level heterogeneity of an area.
Keystone species
exert strong controls on community structure relative to their abundance and size. Examples?
e.g. beavers, wolves, sea otters, bees, etc.
Regulate populations
Nutrient and waste recycling
Enhance habitats
Pollen
small, thick-walled plant structures that contain cells that develop into sperm
Pollination
transfer of pollen from male to female plant structures so fertilization can occur
Insects (bees, etc.) are associated with evolution of flowering plants
Colony collapse disorder (CCD)
Most worker bees in a colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees
