Populations And Ecosystems (Ecology (study of organisms in relationship to…
Populations And Ecosystems
study of organisms in relationship to their surrounding
Population: individuals of the same species togther
Community: all populations together
Ecosystem: community along with nonliving environment
Plants in Relation to their habitat
Environment at the time of deision making
breeding or flowering date
environment at the time of selection
rain, wind, temperature, altitude, soil, pollution, nutrients, pH, types of soil, and sunlight
Latitude and Altitude
Greater Carboxylation efficiency at high altitudes.
Discrimination increases towards the pole. Latitudinally,
decrease in discrimination.
polar low-altitude plants have δ13C values half way between humid tropical lowland and tropical alpine plants.
both temperature and atmospheric pressure are responsible for the altitudinal trends in 13C discrimination.
Temperature effects may partly be related to increased leaf thickness (within the same leaf type) in cold environments.
oxygen partial pressure that is responsible for the pressure related change in discrimination.
Correlations with dry matter partitioning, mesophyll thickness and nitrogen content are also present.
caused by non living factors
natural and integral part of forest ecosystem
cyclones, storms, landslides, insect and disease outbreaks, and heat waves and droughts
The plant itself
other plant species
Organism other than plants
Limiting Factors And Carrying Capacity
resources or other factors in the environment that can lower the population growth rate.
Carrying capacity (K):
maximum population size that can be supported in a particular area without destroying the habitat.
determine the carrying capacity of a
the proportionate numbers of persons in successive age categories in a given population
For prediction of age, ecologists need to know birth and death rates for organisms at different ages as well as the current age and sex makeup of the population.
young individuals? Old individuals? Reproductive age individuals?
Survivorship curves and age structure
graphs that show what fraction of a population survives from one age to the next.
the division of limited resources by species to help avoid competition in an ecological niche.
a representation of the Biotic interactions in an ecosystem, in which species (nodes) are connected by pairwise interactions (links).
trophic or symbiotic
representation of the number of organisms at each level
comparison of environmental and population parameters
(i) r-selected genotypes have a greater developmental speed;
(ii) r-selected genotypes have higher fecundity;
(iii) r-selected genotypes produce more offspring, but invest less energy in each offspring
(iv) r-selected genotypes show less evidence of selection for traits increasing competitive ability in high density situations;
(v) there is a selective trade-off between mechanisms contributing to colonization potential and those contributing to competitive potential.
population samples of three species of Typha