Flashcards in 3.7.2 Populations Deck (19)
What does Hardy Weinberg predict?
The frequency of alleles in a population.
It will stay constant from one generation to the next
Hardy Weinberg principle only holds true if...
There are no mutations, no selection, population is large, mating is random, no migration
p+q = 1. What is this predicting?
Frequency of alleles
p2+2pq+q2 = 1. What is this predicting?
Frequency of genotype
If p = 0.5, what is the frequency of the heterozygotes in the population. Express as a % also.
Define gene pool
All of the alleles of all of the genes in a population
define allele frequency
The number of times a particular allele occurs within the gene pool
The total number of all organisms of one species that occupy a particular area/habitat
Define a species
Group of similar organisms that are capable of reproducing and producing fertile offspring
If the frequency of heterozygous individuals is 10% of the population and the population is 20,000. How many people are heterozygotes?
Define a mutation
Change in the base sequence of DNA - can give rise to new alleles.
Can a mutation be passed onto offspring?
Only if it occurs in the gametes - mutations in normal body cells are not passed onto offspring
Type of nuclear division that leads to the production of gametes - each with a unique combination of alleles
Bell shaped curve known as a ..
Normal distribution curve
Examples of selection pressures..
predation, disease, competition. These pressures vary from time to time and place to place
describe a method that enable you to determine plant species at one particular site
1. A method of selecting sampling sites at random;
2.Use of quadrat;
3.Count number of (different plant) species (at site/in each quadrat);
Why is log scale used on a graph to record number of bacterial cells?
It can accommodate a LARGE range in numbers - allowing patterns and trends to be seen
During population growth of yeast cells, many cells die during the death phase - why?
No glucose left
increased in ethanol production/toxins