4.2.2 Classification and Evolution

Question 1

Classification; taxonomic groups

Answer 1

Kingdom
Phylum 
Class
Order
Family
Genus
Species 

= hierarchical classification
= Linnaean classification

Question 2

Why do scientists classify organisms?

Answer 2

• to identify species
• to predict characteristics
• to find evolutionary links

Question 3

The three domains

Answer 3

Archaea

Bacteria

Eukarya

Question 4

definition of a SPECIES

Answer 4

A group of organisms that are able to reproduce to produce fertile offspring

Question 5

Naming organisms

Answer 5

Genus, species

= binomial nomenclature

Question 6

The five kingdoms

Answer 6

Prokaryotes:
• Prokaryotae (bacteria)

Eukaryotes:
• Protoctista (unicellular)
• Fungi (e.g. yeast,moulds)
• Plantae
• Animalia

Question 7

Prokaryotae

Answer 7

Unicellular

No nucleus or organelles

Ring of naked DNA

No visible feeding mechanism

Question 8

Protoctista

Answer 8

Mainly unicellular

Nucleus and organelles

Some have chloroplasts

Some are sessile, some have cilia/flagella

Nutrients acquired by photosynthesis or ingestion of other organisms or parasitic

Question 9

Fungi

Answer 9

Uni and multicellular

Nucleus and organelles

No chloroplasts

No locomotion

Body made of threads or hyphae

Nutrients acquired by absorption - saprophytic feeders

Most store food as glycogen

Question 10

Plantae

Answer 10

Multicellular

Nucleus and organelles (chloroplasts,cellulose cell wall)

Chlorophyll

Nutrients acquired by photosynthesis - autotrophic (make own food)

Store food as starch

Question 11

Animalia

Answer 11

Multicellular

Nucleus and organelles

No chloroplasts

Move with cilia, flagella, contractile proteins (e.g. muscle organs)

Nutrients via ingestion

Food stored as glycogen

Question 12

Archaebacteria

Answer 12

Aka ancient bacteria

Extreme conditions (thermal vents, anaerobic conditions, acidic environments)

Question 13

Eubacteria

Answer 13

True bacteria

All environments.

Question 14

Three domain, six kingdom system

Answer 14

Bacteria, archaea, eukarya

Eubacteria, archae-bacteria, protoctista, plantae, fungi, animalia

Bacteria/eubacteria and archaea/archaebacteria REPLACE prokaryotes

Question 15

Phylogeny

Answer 15

Name given to evolutionary relationships between organisms

Question 16

Phylogenetics

Answer 16

The study of the evolutionary history of groups of organisms

Question 17

Phylogenetic trees

Answer 17

Represents evolutionary relationships between organisms

Branched diagrams

Earliest at base

Similarities in physical and genetic make up

Much evidence gained from fossils

Question 18

Advantages of phylogenetic classification

Answer 18

• done without reference to Linnaean classification
• classification uses phylogeny for confirmation
• continuous tree

Question 19

Evidence for evolution

Answer 19

• palaeontology - study of fossils
• comparative anatomy
• competitive biochemistry

Question 20

Palaeontology

Answer 20

Fossil records

Allow relationships between extricate and living organisms to be invesigated

Question 21

Comparative anatomy

Answer 21

Homologous structures - same underlying structure
e.g. pentadactyl limb
= common ancestor

Presence of homologous structures provides evidence for divergent evolution. How diff species have evolved from a common ancestor

Question 22

Comparative biochemistry

Answer 22

Sim/diff in proteins and other life process molecules
e.g. cytochrome c (protein in respiration and rRNA)

Changes that don’t affect molecules function are called ‘neutral’

Question 23

Interspecific variation

Answer 23

Variation between members of different species

Question 24

Intraspecific variation

Answer 24

Variation between organisms of the same species

Question 25

Causes of variation

Answer 25

* an organisms genetic material | * the environment in which the organism lives

Question 26

Genetic causes of variation

Answer 26

* alleles - inherited * mutations - in gametes then passed on to offspring or in proteins * meiosis - half genetic info, independent assortment and crossing over * sexual reproduction - info from each parent * chance - fertilisation More variation in organisms that reproduce sexually Blood group determined directly by genetic variation

Question 27

Environmental causes of variation

Answer 27

Plants affected to greater degree die to lack of mobility e.g. access to sun Characteristic determined purely by environmental variation = scars - accident or disease - no genetic origin - not inherited

Question 28

Environmental and genetic causes of variation

Answer 28

Combination e.g. Tall genes vs poor diet ``` Skin colour At birth (inherited) vs exposure to sunlight ``` ‘Nature vs nurture’

Question 29

Discontinuous variation

Answer 29

A characteristic that can only result in certain values e.g variation cause by genetic factors, an animals sex, blood groups e.g in microorganisms, shape of bacteria Bar chart

Question 30

Continuous variation

Answer 30

A characteristic that can take any value within a range Graduation from one end to other = continuum e.g. height and mass of plants/animals Frequency table Histogram

Question 31

Normal distribution curves

Answer 31

Bell shaped curve • mean mode median the same • symmetrical • most values lie close to the mean 68% within 1 s.d. of mean 95% within 2 s.d. of mean 99.7% within 3 s.d. of mean

Question 32

Standard deviation

Answer 32

How spread out the data is | Greater = more spread

Question 33

T test

Answer 33

Compare mean values of two sets of data ``` x1/2 = mean of populations 1/2 Sigma1/2 = standard deviation of p1/2 n1/2 = total no of values in samples 1/2 ``` Null hypothesis = prediction that there’s no significant difference between populations

Question 34

Spearman’s rank correlation coefficient

Answer 34

Two sets of data can show: • no correlation • +ve correlation (as one increases, the other increases) • -ve correlation (as one increases, the other decreases) ``` r5 = correlation coefficient d = difference in ranks n = no of pairs of data ```

Question 35

Adaptations

Answer 35

Anatomical - physical Behavioural - inherited or learned Physiological - internal processes

Question 36

Anatomical adaptations

Answer 36

* body covering * camouflage * teeth * mimicry

Question 37

Adaptations; marram grass

Answer 37

* curled leaves * hairs on inside of leaf * sunken stomata * thick waxy cuticle

Question 38

Behavioural adaptations

Answer 38

``` • survival behaviour • courtship (attract mates) • season behaviours - migration - hibernation ``` ``` Innate/instinctive = inherited Learned = learnt from experience/observation ```

Question 39

Physiological adaptations

Answer 39

* poison production * antibiotic production * water holding

Question 40

Anatomical adaptations; evidence for convergent evolution

Answer 40

Analogous structures = similar role but very different structure = adapted to perform same function but have different genetic origin

Question 41

Convergent evolution

Answer 41

= unrelated species begin to have similar traits • similar environments • other selection pressures

Question 42

Natural selection

Answer 42

1) organisms show variation cause by genes 2) favourable characteristics have increased chance of survival 3) successful organisms pass advantageous characteristic allele to offspring 4) repeated every generation 5) over many generations, leads to evolution of a new species