4.1 - 4.6 : Biodiversity

Question 1

What is the statement on the spec for 4.1 ?

Answer 1

‘over time the variety of life has become extensive but is now being threatened by human activity’.

Question 2

Define the term biodiversity.

Answer 2

The measure of the variety of living organisms present within a particular habitat, ecosystem or the entire plant.

Question 3

What is meant by the term endemism ?

Answer 3

When a species is only found in one geographical location. The Malabar climbing frog is endemic because there is just a single population living in India. Endemic species are vulnerable to extinction.

Question 4

What is the heterozygosity index used for ?

Answer 4

It is used to measure biodiversity within a habitat using species
richness and within a species using genetic diversity.

The higher the number of heterozygotes, the higher the genetic diversity.

Question 5

What is the formula for heterozygosity index (H) ?

Answer 5

Question 6

What is the index of diversity (D) ?

Answer 6

It compares the biodiversity in different habitats. It takes into account both the number of different species and the abundance of each species.
- The larger the value of diversity index, the more biodiverse the habitat is .

Question 7

What is the formula for the index of diversity (D) ?

Answer 7

Question 8

What are the three types of adaptations ?

Answer 8

1. Behavioural (Changes to actions) - e.g hibernation, migration, altered feeding habits and distinct modes of communication. Often crucial for finding food, avoiding predators, or communicating with others.
2. Physiological (changes to bodily/internal processes that help the organism to survive) - e.g venom production, temperature regulation, metabolic rate
3. Anatomical (changes to body structure which increases its chances of survival) - e.g oily fur, polar bears are camouflaged against the snow and cacti have spines to prevent being eaten by animals.

Click here for better explanation link

Question 9

What is meant by the term niche ?

Answer 9

The role that an organism plays in the ecosystem and includes its biotic and abiotic factors.

• Within the same habitat, different organisms will have different niches. If two different organisms occupy the same niche, one will be out-competed by the other until one species survive.

Question 10

What is meant by the term natural selection.

Answer 10

The process which an organism adapts to its environment through selectively reproducing changes in its genotype. The organisms with the best suited characteristics for their environment are more likely to survive and reproduce.

Question 11

Explain how natural selection results in adaptation and evolution.

Answer 11

1. Variation - There is variation within the population. Gene mutations cause new alleles to appear in the population - some of these may be harmful but some may be beneficial or environmental factors or both.
2. Selection pressure - Environmental factors such as predation, competition for resources, diseases or climate change create a selection pressure on the population.
3. Survival of the fittest - Individuals who are best adapted to the environment are more likely to survive and reproduce.
4. Reproduction - The ones that survive reproduce and pass on their alleles to their offspring, and therefore posses new adaptations that allow them to survive in their environment.

Evolution : The frequency of the advantageous allele increase in the population. This is evolution.

Question 12

Explain the term species richness.

Answer 12

The number of species in a community.

Question 13

What is the Hardy-Weinberg principle ?

Answer 13

It allows us to estimate the frequency of alleles in a population, as well as if the frequency is changing over time.

It predicts that the allele frequency will not change between generations.

Question 14

What does the term speciation refer to ?

Answer 14

Speciation refers to the development of a new species.

• It occurs when **two* groups of the population become reproductively isolated from each other.

Question 15

What does reproductive isolation prevent.

Answer 15

• Reproductive isolation prevents the transfer of genes (reduced gene flow) between the two groups so natural selection acts separately on the two sub populations.

Question 16

What are the two types of speciation ?

Answer 16

Allopatric and Sympatric.

Question 17

What can reproductive isolation lead to ?

Answer 17

reproductive isolation can lead to accumulation of different
genetic information in populations, potentially leading to the formation of new species.

Question 18

What assumptions does the Hardy-weinberg principal make ?

Answer 18

1. The population is large
2. No immigration or emigration is occurring
3. Mating is random
4. No new mutations have arisen
5. No natural selection has occurred

Question 19

What can we understand if the allele frequencies change from one generation to the next within a large population.

Answer 19

If the allele frequencies change from one generation to the next within a large population, then we know that mutation, migration, non-random mating or natural selection has taken place.

Question 20

What are the hardy weinberg equations ?

Answer 20

Watch here for better understanding. link

Question 21

What are the consequences of reproductive isolation ?

Answer 21

Question 22

Allopatric speciation

Answer 22

Occurs when populations are geographically this prevent groups from mating.
Causes reproductive isolation
If polyation sizes are small random mutations can cause genetic drift.

Question 23

What is classification.

Answer 23

is a means of organising the variety of life based on relationships between organisms using differences and similarities in phenotypes and in genotypes, and is built around the species concept

Question 24

What is taxonomy

Answer 24

The grouping of organisms according to their characteristics.

Question 25

What is the order of taxonomic groups.

Answer 25

Dear King Phillip Came Over For Good Soup.

Question 26

How has research by the scientific community contributed to classifications of organisms.

Answer 26

New data has led to ne taxonomic groupings, three domains; bacteria, archaea and Eukaryota.