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Question 1

phenotype

Answer 1

appearance of an organism

Question 2

variation

Answer 2

differences within a species

Question 3

genetic variation

Answer 3

the genetic material you inherit from your parents

Question 4

environmental variation

Answer 4

the environment in which you live

Question 5

discontinuous variation

Answer 5

can only result in specific (discrete) values

genetic only

one(or few genes)

eg gender, eye colour

bar chart to show

Question 6

continuous variation

Answer 6

can take any value within a range

genetic and environmental

multiple genes control

eg leaf surface area, length of fur, skin colour

histograms to show (often bars removed and just line showing trend drawn)

Question 7

asexual reproduction

Answer 7

+ if the parent is well adapted to an area, the offspring will share an identical set of characteristics
+ only one parent needed. no need to find a partner. pollination not required in plants. so its faster. large numbers of offspring are produced quickly.
- adverse changes to the biotic or abiotic factors may destroy the species, as all organisms will be affected

Question 8

sexual reproduction

Answer 8

+ variation in offspring leads to adaptations in a species. within the population, some organisms will contain the adaptations required to cope with an environmental pressure. these organisms can reproduce, enabling the population to continue.
+resistance to disease

• reproduction required two parents so, slower- so few offspring produced

Question 9

diploid cells

Answer 9

two sets of each chromosome

Question 10

ova and sperm cells

Answer 10

are haploid cells
one of each chromosome
23

Question 11

fertilisation

Answer 11

two haploid gamete cells join together
forms a diploid cell=zygote
then it divides many times by mitosis to produce a new organism

Question 12

genome

Answer 12

entire genetic material of an organism

Question 13

gametes made how

Answer 13

produced by a type of cell division called meiosis- results in four haploid cells from one diploid parent

Question 14

first stage meiosis

Answer 14

chromosomes are copied
line up along middle of cell in pairs
one member of each pair pulled to opposite ends of the cell
cell then didvide in two
two seperate cells formed

Question 15

second stage meiosis

Answer 15

the chromosomes line up along the middle of each of the two new cells
this time each chromosome pulled in half. single copy of each chromosome goes to opposite ends of the cell
each cell then divides into two, results in 4 haploid

Question 16

alleles/variants

Answer 16

different forms of a gene

Question 17

BB

Answer 17

homozygous dominant

Question 18

bb

Answer 18

homozygous recessive

Question 19

Bb

Answer 19

heterozygous

Question 20

gregor mendel

Answer 20

pea plants experiments
either green or yellow

green pea pod is dominant,yellow recessive

punnet square shows all of offspring= heterozygous so all plants will have green pods because dominant

Question 21

mutation

Answer 21

occurs when the sequence of DNA bases is altered

Question 22

effect of mutation

Answer 22

in most cases, the mutation will not affect an organisms phenotype
some mutations may influence an organisms phenotype
a few mutations will determine an organisms phenotype. these mutations lead to the variation that can be seen within a specie

Question 23

mutations harmful eg (phenotype)

Answer 23

can cause cancer, bare uncontrollable cell division
production of abnormal protein channels (allow molecules to be transported through the cell membrane) that do not function properly, eg cystic fibrosis
cause different shaped protein molecules to be made
eg people w sickle cell have unusually shaped haemoglobin molecules,makes blood cells sickle shaped

Question 24

how can mutations alter an organisms phenotype

Answer 24

a strand of dna is organised into sections of coding DNA (genes), separated by sections of non coding dna

if mutation in gene, dna bases may be changed,added or deleted. this changes the sequence of bases so the order of bases in mrna produced in transcription may be different
in turn the amino acids may be assembled in a different order, wrong protein may be produced or it may fold incorrectly and form a different shape

Question 25

evolution

Answer 25

gradual change in a species over time

Question 26

howdo organisms evolve?

Answer 26

natural selection further mutations increases genetic variation, results in a range of phenotypes these organisms are best suited too their environment and will survive and reproduce -survival of the fittest

Question 27

natural selection process

Answer 27

organisms in a species show variation- caused by differences in their genes organisms with characteristics best adapted to environment survive and reproduce. less well adapted die. survival of fittest genes from successful organisms are passed down to the offspring in the next generations- offspring likely to possess these characteristics process then repeated bare times. over period of time, can lead to new species

Question 28

fossil layers

Answer 28

form a sequence showing that organisms have gradually changed over time=fossil record

Question 29

eg fossilisation

Answer 29

1. reptile dies and falls to ground 2. flesh rots,leaving skeleton to be covered in sand or soil and lay before damaged. 3. protected over millions of years, the skeleton becomes mineralised and turns to rock. the rocks shift in the earth with the fossil trapped inside 4. eventually fossil emerges as the rocks move and erosion takes place

Question 30

evolution evidence

Answer 30

rapid changes in species extinction molecular comparison

Question 31

darwin ahh

Answer 31

joined scientific expedition to galapagos aboard hms beagle, read principles of geology that suggested fossils were evidence of animals tht lived time ago darwin made famous observation on finches closely related birds but beaks+claws diff shapes n sizes released design of finches beaks was linked to food available on each island. bird with break more suited tofoood available survive longer so more offspring,passing on characteristic, over time, finch population would share this =natural selection

Question 32

Ahhlfred russel wahhlace

Answer 32

in borneo working on his own theory of nat selection and evolution sent his ideas to darwin for peer review before publishing his they proposed idea through joint presentation of two scientific papers darwinthen published book to non scientists hugely successful yet controversial

Question 33

why is darwin’s theoyr of evolution now way more widely accepted

Answer 33

fossil record observations of microorganisms extinctions recent advances in dna studies

Question 34

classification

Answer 34

process of sorting living organisms intro groups (share similar features)

Question 35

why do scientists classify organisms

Answer 35

identify species predict characteristics find or show evolutionary links

Question 36

artificial classification

Answer 36

group organisms together using observable characteristics not evolutionary relationships not accurate much

Question 37

binomial nomenclature

Answer 37

first part=genus = surname second=species=firstname

Question 38

phylogeny

Answer 38

study of evolutionary links established by studying similarities and differences in dna between species

Question 39

seven taxonomic levels

Answer 39

kingdom phylum class order family genus species keep phlegm covered or face germ stuff

Question 40

what are fossils

Answer 40

preserved remains or traces of ancient organisms that lived millions of years ago