Topic 4

Question 1

species definition

Answer 1

a group of organisms with similar morphology, physiology and behaviour which can interbreed to produce fertile offspring and are reproductively isolated from other species

Question 2

what is the disadvantage of using DNA analysis to identify species

Answer 2

cannot say whether 2 populations can interbreed to produce fertile offspring

Question 3

population def

Answer 3

a group of interbreeding individuals of the same species found in an area

Question 4

ecological niche

Answer 4

the way an organism exploits its environment

Question 5

what are behavioural adaptations

Answer 5

actions by organisms which helps them survive and reproduce

Question 6

what are physiological adaptations

Answer 6

features of the internal workings of an organism that helps them survive and reproduce

Question 7

example of physiological adaptation

Answer 7

changes in internal biochemical functioning of an organism in response to an altered environmental stimulus

Question 8

what are anatomical adaptations

Answer 8

a physical or structural adaptation- internal or external

e.g. cacti have spines

Question 9

natural selection

Answer 9

change in environment (selective pressure) = change in selective pressures acting on population

allele previously selectively neutral now adv

organisms with allele more likely to survive and reproduce

offspring more likely to have allele so it becomes more common in population

Question 10

evolution def

Answer 10

a change in allele frequency in a population over time

for natural selection to lead to evolution, there must be genetic variation in the population

Question 11

what is a gene pool

Answer 11

consist of all the alleles of the genes present in a population

Question 12

Hardy Weinberg Equation: working out allele frequencies

Answer 12

frequency of homozygous dominant individuals (p squared)

+

frequency of heterozygous individuals (2pq)

+

frequency of homozygous recessive (q squared)

Question 13

what does the ability of a population to adapt to new conditions depend on?

Answer 13

1. size of selection pressure
2. size of gene pool
3. reproductive rate

Question 14

biodiversity def

Answer 14

the variety of species that belong to every different group of organisms

measuring helps focus conservation efforts to vulnerable habitats and species

Question 15

what is the binomial system for naming organims

Answer 15

1st part of name: genus: shared by all closely related species

2nd part: defines particular species in the genus

Question 16

where can scientific findings be reported

Answer 16

scientific journals
conference papers
internet

Question 17

adv peer review

Answer 17

detect invalid claims

adds weight to valid claims

Question 18

what is phenotype result of

Answer 18

interactions between genotype and environment

observable traits

Question 19

sources of genetic variation

Answer 19

meiosis - independent assortment + crossing over

random mutations - change base sequence of DNA in organisms cells, creating new alleles which adds to the gene pool and increases variation

Question 20

how can molecular changes in genetic variation be detected

Answer 20

electrophoresis of proteins: 2 alleles at a single locus produce slightly different protein products

Question 21

how to measure biodiversity

Answer 21

1. species evenness

2. species richness

Question 22

how to calculate species richness

Answer 22

count number of species present in a given habitat

disadvantage
takes no account of population size of each species

Question 23

what are areas of particularly high biodiversity known as

Answer 23

biodiversity hotspots

Question 24

how to measure genetic diversity within a species

Answer 24

directly- DNA sequencing to determine the bases in a segment of DNA, thus determining what alleles are present

indirectly- DNA cut into fragments and separated using electrophoresis. Different alleles identified because they produce fragments of different lengths

Question 25

differences : plant and animal cells

Answer 25

Plant: rigid cell wall and contains chloroplasts; animal cells do not

Question 26

function of chloroplasts

Answer 26

site of photosynthesis- sun energy used to make storage molecules - starch is found in storage vacuoles in cytoplasm (amyoplasts)

Question 27

plant adaptations

Answer 27

big and strong

building tall structure

Question 28

disadvantage plants growing big and strong

Answer 28

can take long time to reach maturity

must be strong enough to hold own weight and withstand wind

Question 29

how do plants build tall structures

Answer 29

1. produce strong cell walls out of cellulose
2. build columns and tubes from specialised cells
3. stiffin some of these specialised cells with polymer LIGNIN

Question 30

characteristics of cellulose

Answer 30

in plant cell walls

polysaccharide
polymer of glucose
made up of B- glucose units
1,4 glycosidic bond- long, unbranched molecule
forms bundles (microfibrils)

Question 31

Microfibrils

Answer 31

strong as LOTS OF hydrogen bonds between cellulose
would in helical arrangement around cell and stuck with polysaccharide glue

successive layers of microfibrils laid down at angles to one another, forming a composite structure

Question 32

polysaccharide glue holding microfibrils together

Answer 32

composed of short, branched polysaccharides - pectins and hemicelluloses

short polysaccharides bind to:

1. surface of cellulose
2. each other and hold cellulose microfibrils together

Question 33

what are pectins

Answer 33

component of middle lamella (region between cell walls and adjacent cells)

act as cement; holds cells together

Question 34

why is cell wall so strong (2)

Answer 34

arrangement of cellulose microfibrils within a matrix of hemicelluloses and reinforced pectins

Microfibrils laid down at diff angles so strong and flexible

Question 35

How to cross the cell wall

Answer 35

narrow fluid filled channels - plasmodesmata cross the cell walls, making the cytoplasm of one cell continuous with the cytoplasm of the next.

cell walls fully permeable to water and solutes

Question 36

xylem vessels

Answer 36

form tubes for water and mineral transport + stiffened cell walls help support plant

Question 37

sclerenchyma fibres

Answer 37

columns of these cells with their stiffened cell walls provide support

Question 38

phloem sieve tube cells

Answer 38

form long tubes for transport of organic solutes (sugars, amino acids).

Question 39

advantages of millennium seed bank

Answer 39

1. collecting small sample of seeds is unlikely to damage wild population
2. seeds small and easy to store
3. seeds can survive in desiccated state for years

Question 40

what happens when seeds collected

Answer 40

identification verified

seeds cleaned and dried and stored at -20

1month after placed in cold storage, sample taken out and germinated on agar plates to ensure seeds survive

germination tested every 10 years

if falls below 75% then seeds grown to produce new seed sample

Question 41

what can seed collections be used for

Answer 41

research

habitat restoration

species reintroduction

Question 42

what do studbooks do

Answer 42

shows history and location of all captive animals of that species in all places which are cooperating in an overall breeding plan

Question 43

what can studbook records be supported by

Answer 43

cytogenetic techniques- looking at chromosome structures and molecular biology: studying nature of genes

important because studbook data may be incomplete and can reveal how closely related individuals are