Upgrade to remove ads
Only $35.99/year

BIOLOGY: population ecology

Terms in this set (22)

recognize that biodiversity includes the diversity of species and ecosystems. define biodiversity:
The range of living organisms and their environments.

Biodiversity refers to the variety of life, from the smallest microbe to the largest animals and plants, the genetic material that gives them their specific characteristics, and the ecosystems in which they survive.
use species diversity indices, species interactions (predation, competition, symbiosis, disease) and abiotic factors (climate, substrate, size/depth of area) to compare ecosystems across spatial and temporal scales

what is predation?
predation: a greater density of prey within a certain area, which may also mean that the population size is larger, than the predators more attracted to these such areas. The prey population will suffer more deaths and a measure of rate can be compared overtime on the ecosystem.
determine diversity of species using measures such as species richness, evenness (relative species abundance), percentage cover, percentage frequency and Simpson's diversity index
Diversity indices and measurements should be supported through fieldwork and based on classification. Measures of biodiversity, i.e. species richness (S) and Simpson's diversity index (D) should be used where applicable.
Formula: The formula used to quantify biodiversity of a habitat is Simpson's diversity index (SDI), shown as:

SDI= 1- (sum of n(n-1))/N(N-1)
where N= the total number of organisms of all species
and n= number of organisms of one species
explain how environmental factors limit the distribution and abundance of species in an ecosystem.
Environmental factors can dictate many aspects of an organism's life, thereby influencing the overall species' abundance. The physical appearance of one is influenced by their environment. For instance one might become rather skinny due to being malnourished; conversely, one could pack on heaps of weight due to overeating.
Autotroph
an autotroph is a first level energy pyramid organism. It takes light energy from the sun and performs photosynthesis. Autotrophs can also be called producers.
Heterotroph
a heterotroph cannot produce its own food/ energy and is a consumer thus, it has to take energy from producers.
species richness
Species richness is a measure of the number of species compared to the number of individuals found in a sample. The larger the sample, the more species are likely to be found. To account for this, in the Menhinick Index, the number of species is divided by the square root of the number of individuals in the sample. See the equation below:
define a clade
the complete group of organisms thought to have descended from a common ancestor
competition
competition: the resources are limited so species need to compete with each other to get the best/most resources. Same species can compete with one another which leads to more deaths and fewer births

competition is one of the main density-dependent limiting factors of population size.
The continued healthy existence of most organisms depends upon abiotic factors such as food, water, space or light.
Symbiosis
symbiosis: mutually beneficial relationships between organisms- an example is a grazing cow and a bird called cattle egret. The birds eat the insects that are attracted to the cow allowing them to have a food source and the cows benefit from the annoying insects keeping away from them.
disease
Disease: when there are more individuals in an area disease can be more easily transmitted between individuals of the population and will reduce the population size. Hence comparing the rates of diseases can give us insights into the broader ecosystem.
biomass
the total mass of of living matter in ecosystem
trophic levels
describe the relative positions of producers and consumers in a food chain.
keystone species
A species that influences the survival of many other species in an ecosystem
what are the five keystone species?
1. predators
2. prey
3. plant
4. links
5. modifiers
What is carrying capacity?
The size of the population that can be supported indefinitely on the available resources and services of that ecosystem.
what are limiting factors?
There is a limit to the number of individuals who can occupy an environment. As population size increases, the demand for resources, such as food, water, shelter and space, also increases. Eventually, there will not be enough resources for each individual.
ecological succession
Ecological succession is the process of the gradual evolution of an ecosystem.
What is primary succession?
Primary succession is the colonisation of plants in a barren place.
secondary succession
Secondary succession is the recolonisation of recently disturbed plant communities.
Pioneer plant species
Pioneer Plant Species are capable of invading bare sites such as a newly exposed soil surface.
climax community
Climax Community is the end-point in succession, where the community has become relatively stable.
Sets found in the same folder