Key concepts

Question 1

Define endemism

Answer 1

A species which only exists in a certain geographical area.

Question 2

Define Species diversity

Answer 2

The number of different species and the abundance of each species in an area
eg-a forest would contain many different species of plants,insects,birds,mammals

Question 3

Define Genetic diversity

Answer 3

The variation of alleles within a species

-eg , human blood in humans is diverse=high genetic diversity within humans

Question 4

How can we measure species diversity?3 steps

Answer 4

1. count number of different species in an area (richness)
2. count the number of individuals in each species(evenness)
3. Use these values to calculate the index of diversity to calculate species diversity

Question 5

What is the formula for index of diversity , what are the symbols representing and what does it measure ?

Answer 5

1. D=N(N-1) / £n(n-1)
2. N= total number of organism of all species , n=total number of organisms of each species individually, £ = sum of
3. Measure species diversity

Question 6

What conclusions can be drawn from calculating the Index of Diversity ?

Answer 6

You can compare the species diversity in different habitats by comparing which has a higher calculated answer

Question 6

What conclusions can be drawn from calculating the Index of Diversity ?

Answer 6

You can compare the species diveristy in different habitats

Question 7

Why is calculating species diversity unreliable ?2 points

Answer 7

1. Only a sample of an area is taken so it is not representative of the whole habitat
2. N and n are estimated

Question 8

What measures are taken in calculating species diversity to make it as fair as possible ? 3 points

Answer 8

• A random sample is taken to prevent bias
• Repeating the process in the same habitat to get a more inclusive result
• Using the same sampling technique when sampling different habitats

Question 9

Define the words phenotypes and genotype

Answer 9

Phenotype= observable characteristics of an organism

Genotype=the genetic constitution of an organism

Question 10

What does a high number of different phenotypes and different alleles indicate?

Answer 10

a high genetic diversity

Question 11

What is the heterozygosity index formula and what does it measure ?

Answer 11

The heterozygosity index measures genetic diversity

H= number of heterozygotes / number of individuals in a population

Question 12

Define a niche

Answer 12

how a species exploits/uses its habitat

Question 13

What happens when two species try occupy the same niche ?

Answer 13

They will compete with eachother , one species will be more successful than the other (dues to adaptation) until one one species is left

Question 14

Describe and explain the three types of adaptations

Answer 14

Behavioural-They way an organism acts to increase its chances of survival -possums playing dead when to escape attack
Physiological- the internal processes in the organisms body to increase survival
Anatomical-Structural features to aid survival

Question 15

How do scientists publish their discoveries

Answer 15

They come up with a theory and test it , tell other scientist who will aslo test out the theory ,If there is supported evidence it is accepted

Question 16

Describe the process of evolution by natural selection

Answer 16

Mutations occur in a population that introduces new alleles , some of these alleles become favourable since they allow the organism to survive.
Selection pressures like disease, create a competition and a struggle for survival
Those who posses the advantageous allele will survive while those who don’t will not
This advantageous allele will be passed onto the offspring through reproduction
Overtime the frequency of the advantageous allele will increase
This leads to evolution over generations as they become more common

Question 17

Define Evolution

Answer 17

The change in allele frequency

Question 18

Define speciation

Answer 18

The development of a new species (through evolution)

Question 19

Three aspects that lead to speciation

Answer 19

Mechanical changes= changes in genitalia that prevent mating
Seasonal changes=Organisms becoming sexually active at different time of the year
Behavioural changes=Chang in courtship rituals that are no longer attractive to the opposite sex

Question 20

Define geographical isolation

Answer 20

When a physical barrier divides a population of species eg, volcanos , mountains, rivers

Question 21

Explain how geographical isolation can lead to speciation

Answer 21

Conditions on either side will be different therefore different alleles will become common on each side, Eventually the different populations will become genetically distinct .
Would have changes so much they can no longer breed to produce fertile offspring
Become reproductively isolated,and become separate species

Question 22

What is the Hardy weinberg formula and what does it predict and mean ?

Answer 22

It predicts allele frequency (population change over time)
It means that allele frequency wont change from one generation to the next (excludes evolution)

p+q=1
p2+2pq+q2=1

Question 23

What is taxonomy ?

Answer 23

The science of classification

Question 24

Name the five kingdoms

Answer 24

Animalia, Protoctista, Prokaryotae,Fungi,Plantae

Question 25

Name the taxonomic groups going down

Answer 25

Domain, Kingdom, Phylum, Class ,Order, Family, Genus ,Species

Question 26

Name the three domains

Answer 26

Bacteria, Archaea, Eukaryota

Question 27

Define molecular Phylogeny

Answer 27

The analysis of different molecules to see how closely related organisms are

Question 28

How can organisms be reclassified

Answer 28

Due to new technology , DNA sequence can be identified and can be significantly different to what it was mistakenly classified as , therefore it is reclassified into a new family

Question 29

How does the scientific community evaluate data?

Answer 29

Findings are published in scientific journals and conferences
and is then further studied in peer reviews

Question 30

What are amyloplasts

Answer 30

Organelles that contain amylopectin enclosed by a double membrane

Question 31

What are tonoplasts

Answer 31

The single membrane around the vacuole to provide strength and structure

Question 32

What is a plasmodesmata?

Answer 32

An extension of the cell cytoplasm between cell walls that transportation of substances

Question 33

What are pits?

Answer 33

Thin sections in cell wall which allow communication between adjacent cells

Question 34

Structure of chloroplasts

Answer 34

Stroma- fluid inside
Thylakoids that include chlorophyll
Grana= collection of thylakoids
Lamellae= connects the thylakoids

Question 35

What is a middle lamellae

Answer 35

In cell walls , made of calcium pectate to hold adjacent cells together