Populations Flashcards
What is a species?
can interbreed to produce fertile offspring, and will be similar to each other while being different to other species
Why are hybrid offspring infertile?
they have an odd diploid number
Why is the phylogenic system described as a hierarchy?
it has groups contained within larger groups, with no overlap
What are organisms grouped according to?
common features and common ancestors
What is a population?
a group of organisms of the same species living in a habitat
What is a community?
all of the populations of all of the species within a particular habitat at the same time
What is species richness?
the number of different types of species in a particular area. the greater the number of species, the greater the richness
What is species evenness?
a comparison of the size of the population of different species in a particular area
What is species diversity?
a measure of how many different species are present in an area, and how many individuals of this species there are
Describe how you would collect a random sample of….?
-use a computer to generate random coordinates
-place quadrat in that random location
-collect all of ….. in the quadrat
How could you estimate the number of …. in an area?
-split areas into squares using a grid
-use a computer to randomly generate coordinates
-place quadrats in this random location
-count the number of …. in the quadrat present
-figure out the mean per quadrat
Why is it important that data is collected from random samples?
to remove bias
Why is it important to use a large number of samples?
-to ensure the sample was representative
-to produce a more reliable mean
-allows you to see anomalous results more easily
Why does biodiversity increase?
more varieties of plants
so more habitats
so more varieties of food sources
Explain when you would use different types of stats tests
chi squared- categories
t- test- means
spearman rank- correlation
What is a niche?
an organisms role within an ecosystem including their position in the food web and habitat
What is carrying capacity?
the maximum stable population size that an ecosystem can support, and it varies due to both biotic and abiotic factors
Name some abiotic factors?
temperature, light, pH, humidity
What is competitive exclusion?
when multiple species occupy exactly the same niche and one outcompetes the other to extinction
What is a fundamental niche?
the range of conditions in which an organism could survive
What is a realised niche?
the range of conditions in which an organism is actually found