Topic 4: Biodiversity and natural resources.

Question 1

Describe Biodiversity.

Answer 1

The variety of living organisms.

Question 2

Name the two ways of measuring Biodiversity.

Answer 2

Species richness.
Genetic diversity.

Question 3

Describe Index of diversity.

Answer 3

A way of comparing diversity between habitats.
N(N-1) D= diversity index.
D=———– N= total number of organisms.
Σ n(n-1) n= total number of organisms of
each species.

Question 4

Describe a niche.

Answer 4

The role an organism inhabits within a community.

Question 5

Name the three types of adaptations.

Answer 5

Anatomical adaptations.
Behavioural adaptations.
Physiological adaptations.

Question 6

Describe anatomical adaptations.

Answer 6

Physical adaptations helping chance of survival.

Question 7

Describe behavioural adaptations.

Answer 7

Changes in behaviour that increase chance of survival.

Question 8

Describe Physiological adaptations.

Answer 8

Process inside the organism helping chances of survival like redistribution of blood to the skin.

Question 9

Describe Natural selection.

Answer 9

The process of filtering individuals who are better suited to survive and pass on advantageous alleles to future generations

Question 10

Define Evolution.

Answer 10

the Process by which frequency of alleles changes over time as a result of natural selection.

Question 11

Describe how evolution happens via natural selection.

Answer 11

A variety of phenotypes exist due to mutation.
An environmental change occurs changing selection pressures.
Some individuals process advantages alleles giving them a advantage allowing them to survive and reproduce.
Advantageous alleles are passed on to offspring.
Over time frequency of alleles in population changes.

Question 12

Describe the Hardy-Weinberg Equation.

Answer 12

Used to estimate the frequency of alleles in a population and to monitor changes in allele frequency.

P+Q=1
P^2+2PQ+Q^2=1

Question 13

Give the 5 conditions for Hardy-Weinberg Equation.

Answer 13

No mutations.
Random mating.
Large population.
Isolated population.
No selection pressures.

Question 14

Define Molecular phylogeny.

Answer 14

The analysis of molecular differences in different organisms to determine the extent of their evolutionary relationship.

Question 15

Name all 6 organelles present in plant cells but not animal cells.

Answer 15

Cell wall.
Plasmodesmata.
Pits.
Chloroplasts.
Amyloplasts.
Vacuole.

Question 16

Describe a plasmodesmata.

Answer 16

An extension of cytoplasm between the cell wall of adjacent cells involved with the transport of substances between them.

Question 17

Describe Pits.

Answer 17

Thin sections of the cell wall which allow communication between adjacent cells.

Question 18

Describe Chloroplasts.

Answer 18

Site of photosynthesis.
Contains stacks of thylakoid membranes called grana which in turn contain chlorophyll.
Grana stacks are connected with thylakoid membrane extensions lamellae.
Grana are surrounded by stroma fluid.
Has a double membrane called the envelope.

Question 19

Describe Amyloplasts.

Answer 19

Organelles, surrounded by a double membrane, which contain amylopectin (starch).

Question 20

Describe Vacuoles.

Answer 20

Contains cell sap and is surrounded by a tonoplast single membraned.

Question 21

Describe Cellulose.

Answer 21

Long unbranched chains of beta glucose joined by glyosidic bonds.

Question 22

Describe Xylem vessels.

Answer 22

Transport water and minerals.
Provide structural support.
Long cylinders made of dead tissue with open ends.
Contain tough lignin.

Question 23

Describe Phloem vessels.

Answer 23

Tubes made of living cells.
Involved in translocation which is the movement of food substances and nutrients.

Question 24

Describe Sclerenchyma fibres.

Answer 24

Provide structural support.
Made of dead cells with a hollow lumen and end walls.
Contain lignin.

Question 25

Describe Parenchyma cells.

Answer 25

Act as packing between other cells and vessels.

Question 26

Describe the 4 uses of plant fibres for humans.

Answer 26

Sustainable and renewable as they can be regrown.
Biodegradable.
Plant fibres are very strong.
Cheaper than oil based fibres.

Question 27

Describe Magnesium ions use in plants.

Answer 27

Involved in chlorophyll production.

Question 28

Describe Nitrate ions use in plants.

Answer 28

Supply nitrogen for making DNA, RNA, proteins and chlorophyll.

Question 29

Describe Calcium ions use in plants.

Answer 29

They form Calcium pectate and part of the cell wall making them essential for growth.

Question 30

Describe Phase 1 of drug testing

Answer 30

A range of doses of the drug are tested on a very small group of people to see if it’s safe to use.

Question 31

Describe Phase 2 of drug testing.

Answer 31

Drug is tested on a small group of patients with the condition to see if it has any effect on the condition.

Question 32

Describe Phase 3 of drug testing.

Answer 32

last phase, large group of patients given drug to assess effectiveness.
Double blind trial involving use of placebo’s.

Question 33

define the two types of conservation.

Answer 33

In-situ= in the organism’s habitat.
Ex-situ= outside the organism’s habitat.

Question 34

Describe Captive breeding programs.

Answer 34

Ex-situ.
Endangered species are carefully bred to increase genetic diversity and population size.
Stud books are kept to prevent inbreeding.
Reintroduction programmes releases captivity bred animals into natural habitats.

Question 35

Describe Seed banks.

Answer 35

Ex-Situ.
Storage of large numbers of seeds in order to conserve genetic diversity and prevent plant species going extinct.
Seeds are periodically tested for viability.