Classification and evolution

Question 1

Classification-

Answer 1

process of putting living things into groups

Question 2

Why we classify things

Answer 2

-convenience
-make study of living things more manageable
-easier to identify organisms
-helps us to see relationships between species

Question 3

8 taxonomic levels

Answer 3

-Domain- archaea, eubacteria, eukaryotae
-Kingdom- plantae, animalia, fungi, protoctista, prokaryotae
-Phylum- organisms with same body plan eg. possession of backbone
-Class- same general traits eg. no. legs
-Order- subdivision of class using additional info eg. carnivore
-Family- closely related eg. within carnivore there’s dog family
-Genus
-Species- basic unit of classification

Question 4

Binomial naming system

Answer 4

-uses genus and species name
-genus= first and always upper case first letter
eg. Homo sapiens - Homo= genus
-devised by Linnaeus
-universal to avoid confusion when using common names

Question 5

Biological definition species-
Phylogenetic definition species-

Answer 5

-group of organisms that can freely interbreed to produce fertile offspring
-group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics

Question 6

Features of prokaryotae

Answer 6

-no nucleus
-loop DNA
-no membrane bound organelles
-smaller + smaller ribosomes

Question 7

Features of protoctista

Answer 7

-eukaryotic
-single celled
-free living
-autotroph or heterotroph

Question 8

Features of fungi

Answer 8

-eukaryotic
-walls of chitin
-free living
-saprophytic as they cause decay

Question 9

Feature of plantae

Answer 9

-eukaryotic
-multicellular
-cellulose cell wall
-autotrophic- absorb simple molecules and build them into larger molecules

Question 10

Features of animalia

Answer 10

-eukaryotic
-multicellular
-heterotrophic- digest larger molecules into smaller ones

Question 11

Using bio mols in classification

Answer 11

-two unrelated species could adapt in similar ways and therefore look similar= convergent evolution
-therefore classifying based off physical appearance isn’t accurate
Cytochrome C
-protein used in respiration
-amino acids in cytochrome c can be identified as there’s slight differences between species
-compare sequences to find how closely related organisms are
DNA
-compare DNA sequences in different organisms

Question 12

Phylogeny-

Answer 12

-study of evolutionary relationships between organisms
-use phylogenetic trees to see how closely related species are by looking for common ancestors

Question 13

2 types classification

Answer 13

Artificial
-based on few characteristics
-doesn’t reflect evolutionary relationships
-limited info
-stable
Natural
-many characteristics
-reflects evolutionary relationships
-lots of info
-changes over time

Question 14

Darwin’s observations when studying natural selection

Answer 14

-offspring generally appear similar to their parents
-not 2 individuals are identical
-organisms have the ability to produce large amounts of offspring
-populations in nature tend to remain a stable size

Question 15

Darwin’s conclusions when studying natural selection

Answer 15

-there’s a struggle to survive
-better adapted individuals survive and pass their genes on
-over time a number of changes give rise to a new species

Question 16

Evidence for evolution

Answer 16

Fossils
-world was inhabited by species different to those present today
-old species have died out and new ones arisen
-new species are often similar to old ones
Biological molecules
-certain molecules present throughout the living world, suggesting we evolved form one common ancestor
-2 closely related species are likely to have similar/ identical bio mols

Question 17

4 types variation

Answer 17

Intraspecific
- variation within a species eg. hair colour
Interspecific
-variation between individuals of different species
Continuous
-variation where there are 2 extremes and a full range of values between eg. height
Discontinuous
-where there are distinct categories, nothing in between eg. gender

Question 18

3 causes of variation

Answer 18

Genetic variation
-genes we inherit determine out characteristics
-the combination of alleles we inherit is different to every other living thing
Environmental
-variation caused by response to environmental factors eg. tanning in sun
Combined effects
-environmental and genetic variation aren’t isolated, they interact eg. height, dependent on genes and amount of food

Question 19

Standard deviation

Answer 19

-measures the spread around the mean
-large SD = large spread = inconsistent
FORMULA GIVEN
x= individual value
x line above= mean
n= number data points

Question 20

Student t test

Answer 20

-compare 2 means
-tests whether the difference between them is significant or not
FORMULA GIVEN
x1 line above= mean first data set
x2 line above= mean 2nd data set
n1= number data points in data set 1
n2= number data points in data set 2
S1= SD data set 1
s2= SD in data set 2
Degrees of freedom= sample size- number of data sets
-calculate value greater than critical= significant

Question 21

Correlation coefficient
D=
n=

Answer 21

-used to consider the relationship between 2 data sets
FORMULA GIVEN
D= difference between ranks
n= number of pairs of values

Question 22

Adaptation

Answer 22

-characteristic that enhances survival in a habitat

Question 23

3 types adaptations

Answer 23

Anatomical- structural features
Behavioural- way behaviour is modified for survival
Physiological- affect the way processes work

Question 24

Anatomical adaptations marram grass

Answer 24

-long roots to reach water underground
-curled leaves for reduced SA
-low stomata density so less water vapour lost
-thick waxy cuticle to reduce evaporation

Question 25

Behavioural adaptations of marram grass

Answer 25

-shortage of water by rolling leaves tightly and closing stomata
-when covered by sand, grows quicker to reach sunlight

Question 26

Physiological adaptations of marram grass

Answer 26

-rolls leaf due to hinge cells in lower epidermis, which lose water and lose their turgidity, causing leaf to roll
-cell water potential lower than other plants to survive salty conditions

Question 27

Convergent evolution

Answer 27

process whereby an organism not closely related independently evolve similar characteristics as a result of being adapted to similar environments or niches

Question 28

How natural selection works

Answer 28

-mutations create alternative versions of gene= allele
-this creates genetic variation between individuals of same species= intraspecific
-environment selects the most advantageous characteristics
-these organisms will survive and reproduce
-pass on advantageous genes to next gen
-next gen has higher proportion of individuals with successful characteristics