Population ecology Flashcards
Individual
A single, separate organism (animal or plant) distinguished from others of a same kind.
Population
A population is the number of organisms of the same species that live in a particular geographic area at the same time, with the capability of interbreeding.
Community
An interacting group of various species in a common location.
Ecosystem
An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system.
What affects the size of a population?
the size of a population is affected by immigration, emigration, mortality and births. Population size fluctuates seasonally and annually, depending on resource availability.
What are the effects of limiting factors on population growth?
Limiting factors are resources or other factors in the environment that can lower the population growth rate. Limiting factors include a low food supply and lack of space. Limiting factors can lower birth rates, increase death rates, or lead to emigration.
Name three sampling methods.
Mark recapture, Quadrant, and Census
Importance of random sampling.
Random sampling ensures that results obtained from your sample should approximate what would have been obtained if the entire population had been measured.
What is a predator-prey relationship?
The predator-prey relationship consists of the interactions between two species and their consequent effects on each other. In the predator-prey relationship, one species is feeding on the other species. I.E. Lion-Zebra and Shark-fish.
What is the impact of food webs and social organisations on populations?
If one trophic level’s population increases or decreases too much it can decrease the amount of producers, thus decreasing the amount of energy available in the food web, which can cause a population crash.
What is interspecific competition?
A process in which two different species compete for the same resources. e.g. Food, and space.
What is the intraspecific competition?
A process in which individuals of the same species compete for various resources such as mating partners.
Ways of reducing competition.
Resource partitioning (Plants) Coexistence (Animals)
Explain the concept of ecological succession
the sequence of organisms that occupy a new habitat (primary succession) or a disturbed habitat (secondary succession). Pioneers are replaced by a succession of
species; numerous possible endpoints, depending on environmental fluctuations; variety and number of species determined by constraints of succession.
Pioneer species
The pioneer species are hardy species which are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by fire.
How does social organisation enhance survival?
benefits of herds or flocks as a predator avoidance strategy as in zebra
• packs as a successful hunting strategy as in wild dogs
• animals with a dominant breeding pair as in wild dogs
• division of tasks among castes as in termites
Environment
External factors, biotic & abiotic surrounding an organism which influences its development and survival.
Habitat
The specific environment in which a plant or animal species normally occurs.
Population size
The total number of individuals in a population.
Population Density
The number of individual of a population per unit area.
Natality
The birth rate of a population, normally expressed as the number of live births per thousand individuals per year.
Mortality
The death rate of a population normally expressed as the number of deaths per thousand individuals per year.
Immigration
The one-way movement of organisms into an area where they become established.
Emigration
The one-way movement of organisms out of an area to become established.
Predation
The feeding interaction where one organism, the predator, hunts, kills and eats another organism, the prey.
Competition
Takes place when two or more individuals or more individuals compete for the same limited resources, such as food, water, space and other resources.
How to get a reliable population through quadrat number
Counting number of individuals in quadrat accurately
Knowing the area of each quadrat
Random distribution of each quadrat
Use of a large enough number of quadrats to obtain an average
How to get a reliable population number through mark recapture
Marking musn’t harm organism
Must not wear off during period of inspection
Organism should be able to reintegrate into population
Population should be closed
There are no births or deaths during investigation
Resource partioning
When the niche of two individuals overlay, resources can be partitioned such as feeding at different times or using different parts of the same resource so that they avoid having to compete.
