3.7.2 Populations

Question 1

What does Hardy Weinberg predict?

Answer 1

The frequency of alleles in a population.

It will stay constant from one generation to the next

Question 2

Hardy Weinberg principle only holds true if…

Answer 2

There are no mutations, no selection, population is large, mating is random, no migration

Question 3

p+q = 1. What is this predicting?

Answer 3

Frequency of alleles

Question 4

p2+2pq+q2 = 1. What is this predicting?

Answer 4

Frequency of genotype

Question 5

If p = 0.5, what is the frequency of the heterozygotes in the population. Express as a % also.

Answer 5

0.5, 50%

Question 6

Define gene pool

Answer 6

All of the alleles of all of the genes in a population

Question 7

define allele frequency

Answer 7

The number of times a particular allele occurs within the gene pool

Question 8

Define population

Answer 8

The total number of all organisms of one species that occupy a particular area/habitat

Question 9

Define a species

Answer 9

Group of similar organisms that are capable of reproducing and producing fertile offspring

Question 10

If the frequency of heterozygous individuals is 10% of the population and the population is 20,000. How many people are heterozygotes?

Answer 10

2000 people

Question 11

Define a mutation

Answer 11

Change in the base sequence of DNA - can give rise to new alleles.

Question 12

Can a mutation be passed onto offspring?

Answer 12

Only if it occurs in the gametes - mutations in normal body cells are not passed onto offspring

Question 13

Define Meiosis

Answer 13

Type of nuclear division that leads to the production of gametes - each with a unique combination of alleles

Question 14

Bell shaped curve known as a ..

Answer 14

Normal distribution curve

Question 15

Examples of selection pressures..

Answer 15

predation, disease, competition. These pressures vary from time to time and place to place

Question 16

describe a method that enable you to determine plant species at one particular site

Answer 16

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);

Question 17

Why is log scale used on a graph to record number of bacterial cells?

Answer 17

It can accommodate a LARGE range in numbers - allowing patterns and trends to be seen

Question 18

During population growth of yeast cells, many cells die during the death phase - why?

Answer 18

No glucose left

increased in ethanol production/toxins

Question 19

Describe how you would determine the mean % cover of grass on the sand dunes?

Answer 19

1. use random number table to sample randomly
2. take many samples
3. divide the total % in all samples by the no. of quadrats taken.