BIOB50H3 Chapter Notes - Chapter L#7: Hawaiian Hoary Bat, Transect, Soil Ph
CHAPTER 9: POPULATION DISTRIBUTION AND ABUNDANCE (LECTURE #7), pages 205-220
-Abundance: the number of indiv. Of a species that are found in a given area
POPULATIONS (9.1)
- Population: a group of individuals of the same species that live within a particular area
and interact w/ one another (interactions can range from sexual reproduction to
competing for food)
incorporates the area over which members of a species interact if that area is
known, we can report population abundance either as population size or as
population density
ofinding total area occupied by a pop. Is hard to find eg. Pollen blows far
omost use best info. Available to estimate size and density of the population
Abundance changes over time and space
- pop. Changes over time true regardless of measuring abundance in small spatial scale
or large scale
eg. Herbivorous Insect abundances on golden rod plants changed in any given time
of the year, and vary from one site to another
for ball gall gly, abundances vary very little
Dispersal links populations
- diff. org. differs in their capacity for movements (eg. Plants storms can transport seeds
thousands of kilometers, but usually their dispersal is small // sometimes their
“dispersal” is so small it isn’t even considered one)
- when dispersal distances are small, pop. Of interacting indiv. Are found in small areas
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- pop. May exist in a series of habitat patches/fragments that
are spatially isolated, but linked by dispersal
patches can result from abiotic factors
also from human interactions
What are individuals?
- It can be hard to determine spatial extent of a population (if
the species dispersal capabilities are poorly understood)
-Clones: genetically identical copies of itself eg. Aspens
produce clones from making new plants from root buds,
while strawberries do this by forming new plants form buds
located on horizontal stems (called runners)
- Some animals, corals and hydroids can form genetically
identical clones, as can some frogs/insects/fishes etc.
- Biologists define indiv. In different ways
Eg. Indiv. Can be defined as the product of a single
fertilization event under this, a grove of genetically
identical aspen trees is a single genetic individual (a
genet) however: are generally indep. Of eachother and
may compete for resources thus: potentially
independent members of a genet are called ramets
DISTRIBUTION AND ABUNDANCE (9.2)
Habitat suitability limits distribution and abundance
- What factors make habitat suitable?
a) ABIOTIC FEATURES OF THE ENVIRONMENT
- Features like: salt, soil pH, available nutrients set limits on what species are suitable for
it
Eg. Creosote bush board distribution in NA deserts (very tolerant of arid
conditions), also tolerates cold well
Eg. Saguaro cactus has a limited distribution flourishes under arid conditions, and
stores most of water during wet conditions, but cannot tolerate cold
b) BIOTIC FEATURES OF THE ENVIRONMENT
- If species one feeds on aren’t present, then the species cannot survive org. can be
excluded from area by herbivores, predators, competition, pathogens etc.
Eg. Optunia strictia cactus that rapidly covered South Wales, Austrailia
introduced moth cactorum greatly controlled the cacti
c) INTERACTIOSN BETWEEN ABIOTIC AND BIOTIC FEATURES
- Many times, the features work together
Eg. Barnacle semibalanus balanoides cannot survive when summer air temp >
25*C or reproduce in winter temp <10*C barnacle is absent from occupying the
entire Pacific coast of NA b/c comp. in lower portion, and cold temp. at the upper
portion
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Chapter 9: population distribution and abundance (lecture #7), pages 205-220. Of a species that are found in a given area. Population: a group of individuals of the same species that live within a particular area and interact w/ one another (interactions can range from sexual reproduction to competing for food) Incorporates the area over which members of a species interact if that area is known, we can report population abundance either as population size or as population density: finding total area occupied by a pop. Is hard to find eg. pollen blows far: most use best info. Available to estimate size and density of the population. Changes over time true regardless of measuring abundance in small spatial scale or large scale. Eg. herbivorous insect abundances on golden rod plants changed in any given time of the year, and vary from one site to another. For ball gall gly, abundances vary very little.
