topic 7 Flashcards
What is a habitat?
the place where an organism lives
what is a population?
all the organisms of one species in a habitat
what is a community?
populations of different species in a habitat
what are abiotic conditions?
the non-living features of an ecosystem e.g. temperature and availability of water
what are biotic conditions?
the living features of an ecosystem e.g. the presence of predators or food
what is a niche?
the role of a species within its habitat e.g. what it eats, where and when it feeds
a niche can only be occupied by one species
if 2 species try to occupy the same niche, one will outcompete the other
what is an adaptation?
a feature that members of a species have that increases their chance of survival/reproduction
what is the carrying capacity of a species?
the maximum stable population size of a species that an ecosystem can support
what is interspecific competition?
organisms of different species compete with eachother for the same resources - both populations have limited resources
if one species is better adapted to its surroundings than the other, they will outcompete the other species
what is intraspecific competition?
when the same species compete with each other for resources
-many resources, population grows
-resources become limited, some of the population dies
-resources grow again, so does population
How are predator and prey population sizes linked?
-prey pop. increases, more for for predators
-predator pop. increases, less prey available to eat
-predator pop. decreases, prey pop. increases as less being eaten by predators
How do you take a random sample of a population?
- choose a smaller area within the area you are investigating
-samples should be random to avoid bias, e.g. divide area into a grid to form coordinates and use a random number generator to choose the coordinates for you
-choose an appropriate sampling technique (e.g. quadratting)
-repeat the process, taking as many samples as possible
-the number of individuals in the whole area can be estimated by taking the mean of the data collected in the sampling and multiplying it by the size of the whole area
How do you use a quadrat?
a quadrat is a square frame ,usually divided into a grid of 100 smaller squares
-quadrats are placed on the ground at different points within the investigation area
-the species frequency or the number of individuals of each species is recorded in each quadrat
How do you use the mark-release-recapture technique?
-capture a sample of a species using an appropriate technique and count them
-mark them in a harmless way
-release back into habitat
-wait a week, then take a second sample from the same population
-count how many of the the second sample are marked
use this equation to estimate entire population size
total pop. size = no. caught in 1st sample x no. caught in second sample / number marked in 2nd sample
What is succession?
