Ecology Basics
A term that includes a group of individuals of the same species living in an area.
POPULATION
What is carrying capacity?
The size of the population that can be supported indefinitely on the available resources and services of that ecosystem
Principle that states that two organisms cannot occupy the same niche.
Competitive Exclusion principle
(PRIMARY) PRODUCERS
A square frame of known area placed randomly or systematically in a habitat to count organisms
A group of populations of different species in an area.
COMMUNITY
Example of a density-dependent factor that affects population growth
predation, disease, competition, availability of resources
Interaction between species where both species benefit
MUTUALISM
Rule of thumb: The amount of energy that flows from one trophic level to the next - in percentage
10%
Difference between a line and belt transect
Line transect = record organisms touching or near a line.
Belt transect = record organisms within a strip of defined width along the line
Includes living things that affect species distribution; such as food resources, parasites, and predators.
BIOTIC FACTORS
Two features of an R-strategist
Any of:
high reproductive rate, little parental care, small body size, short life span, high mortality, opportunists
A species which has a disproportionately large impact on its environment relative to its abundance, playing a critical role in maintaining the structure and diversity of an ecosystem.
KEYSTONE SPECIES
Role of nitrogen fixing bacteria in the nitrogen cycle.
converts N2 in the atmosphere into ammonium/ammonia (NH3/NH4+)
Type of sampling that would use a number generator to select quadrat location.
random sampling
Includes non-living factors- such as sunlight, temperature, and salinity- that affect species distribution.
ABIOTIC FACTORS
Type of growth curve shown by a K-strategist
Logistic (S curve)
Interaction between 2 species where one benefits and the other is not affected in either a positive or negative way.
COMMENSALISM
Name of two processes that convert carbon as it moves through the carbon cycle
An example of how sampling data may be biased
any answer that results in data that is not representative of the whole population. E.g. only sampling certain areas /ignoring other areas
What is the niche of an organism?
The role and space that an organism fills in an ecosystem, including all its interactions with the biotic and abiotic factors of its environment
A population of wallabies in a reserve was estimated at 1,200 individuals in January. By the following January, the population had grown to 1,500 individuals. What is the population growth rate (%) ?
(1500-1200)/1200 x 100 = 25%
The difference between primary and secondary succession
Primary succession - occurs in an area where no soil or life previously existed
Secondary succession - occurs in an area where a community has been disturbed or removed but soil remains
Difference between gross productivity and net productivity.
Gross productivity = total amount of energy fixed at a trophic level
Net productivity = The amount of energy fixed at a trophic level, once energy loss due to metabolism / respiration is removed.
A group of biology students is studying the population size of freshwater yabbies in a dam. On Day 1, they catch and mark 60 yabbies before releasing them back into the dam. On Day 2, they recapture 75 yabbies, of which 15 are marked. Using the Lincoln Index, estimate the total population of yabbies in the dam.
(60x75) / 15 = 300 yabbies