Classification and Biodiversity Flashcards
What is Biodiversity?
a measure of the number and variety of organisms found in a specific geographical habitat
What is a species?
a group of organisms sharing a large number of common characteristics that can interbreed to produce fertile offspring
How is number of species distributed across the globe?
number of species per km^2 increases as you move from the poles to the tropics/equator
What 3 factors can alter biodiversity over time?
human action, succession, and natural selection
Which pole has polar bears?
the north pole (arctic circle)
Which pole has penguins?
south pole
How many major extinctions have there been shown by fossil record?
5
When was the largest major extinction?
250 million years ago. 80% of Earth’s species became extinct
What do extinctions do to biodiversity?
they reduce it, act as a bottleneck for biodiversity
What is the Simpson’s Index?
a calculation done by ecologists that is a measure of diversity which takes into account both richness and evenness of species
What does species richness mean?
number of species present
How is there biodiversity within a species?
same species have same genes but different combinations of alleles
genetic diversity
gene pool
polymorphism
What is genetic diversity?
number of different alleles present in the gene pool
What is the gene pool?
a collection of genes in that species
What is polymorphism?
different types/morphs of one species
polymorphic genes have more than 1 allele at each locus
What are 2 examples of polymorphic species?
Peppered moth (Biston betularia)
Cepea nemoralis
What causes the varying pigementation of bands on the shell of Cepea nemoralis?
controlled by 4 alleles at 1 locus
What is the yellow, pink or brown colour of Cepea nemoralis controlled by?
6 alleles at 1 locus