Classification and Evolution

Question 1

Define the term Classification

Answer 1

The act of arranging organisms into groups based on their similarities and differences

Question 2

Define the term taxonomy

Answer 2

The study of classification

Question 3

Define the term taxonomic group

Answer 3

The hierarchical groups of classification- domain, kingdom, phylum, class, order, family, genus, species

Question 4

Define hierarchical

Answer 4

Arranged so that each entity is subordinate to a different entity.

Question 5

Define phylogeny

Answer 5

The evolutionary relationships between organisms

Question 6

List the seven taxonomic groups, in order, from the broadest to the smallest.

Answer 6

Domain, kingdom, phylum, class, order, family, genus, species

Question 7

Name the taxonomic level that has been added above kingdom.

Answer 7

Domain

Question 8

Give 3 reasons why scientists classify organisms.

Answer 8

1. To identify species- by using defined system of classification, the species an organism belongs to can be easily identified.
2. To predict characteristics- if several members in a group have a specific characteristic, it’s likely other species in the group will have the same characteristic
3. To find evolutionary links- species in the same group probably share characteristics as they have evolved from a common ancestor

Question 9

Define the term “species”.

Answer 9

The smallest and most specific taxanomic group. A species are a group of organisms that are able to reproduce and produce fertile offspring.

Question 10

Explain why horses and donkeys are separate species, and why mules are not given a scientific name and are not a separate species.

Answer 10

When horses and donkeys breed they produce infertile offspring.
Mules are the offspring of a donkey and a horse. they are infertile because their cells contain an odd number of chromosomes. Because it’s infertile they are not classified as a species- so no scientific name

Question 11

Define scientific name

Answer 11

The taxonomic name of an organism that consists of its genus and species

Question 12

Define binomial nomenculture

Answer 12

The scientific naming of a species with a Latin name made of two parts- the first indicating the genus and the second the species

Question 13

Define generic name

Answer 13

The first word in binomial nomenculture that indicates the an organism’s genus.

Question 14

Define specific name

Answer 14

The second word in binomial nomenculture that indicates the organism’s species

Question 15

Explain how scientific names of species are derived from the classification of a species and state the conventions used in writing them.

Answer 15

Write in italics or underline the name. It should be written in lower case except for the first letter of the genus name.

Question 16

Name the 5 kingdoms and give examples of the organisms they contain.

Answer 16

1. Prokaryotae (bacteria)
2. Protoctista (the unicellular eukaryotes) Amoeba.
3. Fungi (yeasts, moulds, mushroom)
4. Plantae (the plants)
5. Animalia (animals)

Question 17

Describe the characteristics of Prokaryotae

Answer 17

1. Unicellular
2. No nucleus or other membrane bound organelles- a ring of naked DNA- small ribosomes
3. No visible feeding mechanism- nutrients are absorbed through cell wall or produced internally by photosynthesis.

Question 18

Describe the characteristics of Protocista

Answer 18

1. Mainly unicellular
2. A nucleus and other membrane-bound organelles
3. Some have chloroplasts
4. Some are sessile but others move by cilia or flagella or amoeboid mechanisms
5. Nutrients are acquired by photosynthesis (autotrophic feeders), ingestion of other organisms (heterotrophic feeders) or both, some are parasitic

Question 19

Describe the characteristics of Fungi

Answer 19

1. Unicellular, multicellular
2. A nucleus and other membrane-bound organelles and a cell wall mainly composed of chitin
3. No chloroplasts or chlorophyll
4. No mechanisms for locomotion
5. Most have a body or mycelium made of threads or hyphae.
6. Nutrients are acquired by absorption- mainly decaying material- they are saprophytic feeders- some are parasitic.
7. Most store their food as glycogen

Question 20

Describe the characteristics of Plantae

Answer 20

1. Multicellular
2. A nucleus and other membrane-bound organelles including chloroplasts, and a cell wall mainly composed of cellulose
3. All contain chlorophyll
4. Most do not move, although gametes of some plants move using cilia or flagella
5. Nutrients are acquired by photosynthesis- they are autotrophic feeders- organisms that make their own food.
6. Store food as starch

Question 21

Describe the characteristics of Animalia

Answer 21

1. Multicellular
2. A nucleus and other membrane-bound organelles (no cell walls)
3. No chloroplasts
4. Move with the aid of cilia, flagella, or contractile proteins, sometimes in the form of muscular organs
5. Nutrients are acquired by ingestion- they are heterotrophic feeders
6. Food stored as glycogen

Question 22

State the 3 domains of life and the 6 kingdoms in the ‘Three Domain system’- Woese’s system

Answer 22

1. Domains- Bacteria, Archaea and eukarya

2. Kingdoms- Eubacteria, archae-bacteria, protoctista, plantae, fungi, animalia

Question 23

Describe the characteristic features of Bacteria

Answer 23

1. Have 70s ribosomes

2. RNA polymerase contains 5 proteins

Question 24

Describe the characteristic features of Archaea

Answer 24

1. Have 70s ribosomes

2. RNA polymerase of different organisms contain between eight and 10 proteins.

Question 25

Describe the characteristic features of Eukarya

Answer 25

1. Have 80s ribosomes | 2. RNA polymerase contains 12 proteins

Question 26

Describe the evidence used to create the “Three Domain System” of classification.

Answer 26

1. Groups organisms using differences in the sequences of nucleotides in the cells' ribosomal RNA 2. A well as the cells' membrane lipid structure 3. And their sensitivity to antibiotics 4. Scientists can discover evolutionary relationships between organisms by comparing DNA and protein structure.

Question 27

Define phylogeny

Answer 27

The study of living organisms based on their evolutionary relationships

Question 28

Define phylogenetic tree

Answer 28

It is a diagram used to represent evolutionary relationships between organisms. Shows common ancestors

Question 29

Define the term sister group

Answer 29

Two descendants that split form the same node are called sister groups

Question 30

Define node

Answer 30

The points where new lines branch off

Question 31

Define tip

Answer 31

Tips on phylogenetic trees represent groups of descendant organisms.

Question 32

Describe the advantages of using phylogenetic trees as a form of classification as opposed to just using taxonomic groupings.

Answer 32

1. Uses phylogeny to confirm classification groups or caused them to be changed. 2. Produces continuous tree whereas classification requires discrete taxonomical groups- scientists aren't forced to put organisms into a specific group that they don't quite fit. 3. The hierarchical classification can be misleading as it implies different groups within the same rank are equivalent.

Question 33

State 3 different sources of evidence for evolution

Answer 33

1. Palaeontology- study of fossils and the fossil record 2. Comparative anatomy- the study of similarities and differences between organism's anatomy 3. Comparative biochemistry- similarities and differences between the chemical makeup of organisms

Question 34

Explain how the fossil record provides evidence for evolution.

Answer 34

1. Fossils of simpler organisms are found in the oldest rocks, whilst fossils of more complex organisms are found in more recent rocks. 2. Sequence in which organisms are found matches their ecological links with each other-plant fossils found before animal fossils. 3. Study similarities in anatomy of fossil organisms- shows how closely related organisms have evolved from the same ancestor

Question 35

Explain how the (relative) age of fossils can be determined.

Answer 35

1. Sediment is deposited on the earth to form layers of rock. 2. Different layers correspond to different geological eras. 3. Within the different rock layers the fossils found are quite different - forms sequence form oldest to youngest- shows how organisms have gradually changed.

Question 36

Explain how comparative anatomy provides evidence for evolution.

Answer 36

1. The presence of homologous structures provides evidence for divergent evolution.- describes how, from a common ancestor, different species have evolved.

Question 37

Define divergent evolution

Answer 37

Species diverge over time into two different species, resulting on a new species becoming less like the original one

Question 38

Define homologous structre

Answer 38

A homologous structure is a structure that appears superficially different in different organisms but has the same underlying structure.

Question 39

Explain how comparative biochemistry provides evidence for evolution

Answer 39

1. Study of similarities and differences in the proteins and other molecules that control life processes. 2. These molecules change over time but some important ones are highly conserved among species 3. Slight changes that occur in these molecules can help identify evolutionary links 4. Two most common molecules studied are cytochrome c (proteins involved in respiration) and ribosomal RNA. 5. Molecular sequence of a particular molecule is compared-look at order of DNA bases or order of amino acids 6. Neutral substitution is changes that do not affect a molecule's function, they occur at a fairly regular rate 7. The number of differences are plotted against the rate the molecule undergoes neutral base pair substitution. 8. From this the point at which the two species last shared a common ancestor can be estimated.

Question 40

Summarise how Darwin and Wallace formulated the theory of evolution by natural selection.

Answer 40

He noticed that different islands had different finches- different beaks 2. He realised the design of the beaks was linked to the food available. 3. A bird born with a beak more suited to the food would survive longer and have more offspring, passing on its character.

Question 41

Define the term variation

Answer 41

The differences in characteristics between organisms are called variation

Question 42

Define interspecific variation

Answer 42

The differences between organisms of different species

Question 43

Define intraspecific variations

Answer 43

The differences between organisms of the same species

Question 44

Name and describe the two causes of variation.

Answer 44

1. An organism's genetic material- differences in the genetic material an organism inherits from its parents leads to genetic variation 2. The environment in which the organism lives- this causes environmental variation.

Question 45

Describe 5 causes of genetic variation between individuals within a population.

Answer 45

1. Alleles- with a gene for a particular characteristic, different alleles produce different affects. Individuals in a species population may inherit different alleles of a gene. 2. Mutations- Changes to the DNA sequence and therefore to genes can lead to changes in the proteins that are coded for. 3. Meiosis- gametes are produced by meiosis. Each gamete receives half the genetic content of a parent cell. The genetic material is mixed up by independent assortment and crossing over. 4. Sexual reproduction- offspring produced from tow individuals inherits genes form each of the parents 5. Chance- different gametes are produced and in reproduction it is chance as to which two combine- individuals differ from siblings

Question 46

State 3 characteristics which are solely genetically determined

Answer 46

1. blood group 2. eye colour 3. shape of ear lobes

Question 47

State 2 characteristics which are solely environmentally determined

Answer 47

1. Scars | 2. piercings

Question 48

State 3 characteristics which are determined by a combination of environment and genetics

Answer 48

1. Skin colour 2. Height/weight 3. hair colour

Question 49

Define the term continuous variation

Answer 49

A characteristic that can take any value any value within a range e.g height

Question 50

Define the term discontinuous variation

Answer 50

A characteristic that can only result in discrete values e.g. blood type

Question 51

Describe the causes of variation that result in discontinuous variation.

Answer 51

Variation determined purely by genetic factors falls into the discontinuous category. Most characteristics are controlled by a single gene.

Question 52

Describe the term polygenic

Answer 52

A characteristic that is controlled by a group of genes

Question 53

Describe the term multifactorial

Answer 53

Characteristics which are dependent on a number of factors.

Question 54

Describe the causes of variation that result in continuous variation.

Answer 54

Characteristics which show continuous variation are controlled by a number of genes and are also often influenced by environmental factors.

Question 55

State the types of graph used to represent continuous and discontinuous variation within a population.

Answer 55

Continuous- frequency tables which are then plotted onto a histogram, a curve is then normally drawn to show a trend. Discontinuous- bar chart, pie chart.

Question 56

Describe histograms

Answer 56

``` X-axis - class width- write measuring thing- height etc. Y-axis - Frequency density= frequency/class width ```

Question 57

Define the term “normal distribution curve” and give 4 characteristics of a normal distribution.

Answer 57

1. Bell-shaped curve- with the peak at the mean Characteristics: 1. Mean, median and mode are the same 2. Curve is symmetrical around the mean 3. 50% are below and 50% are above the mean 4. Most values lie close to the mean

Question 58

Define standard deviation

Answer 58

How spread out the data is. The greater the deviation the greater the spread of data

Question 59

Describe the meaning of each of the symbols in the equation for calculating standard deviation.

Answer 59

Look it up and remember how to use graphical calculator

Question 60

Explain why statistical tests are important and what they are used for.

Answer 60

Statistical tests can be used by scientists to determine the significance of data collected.

Question 61

Define the terms “hypothesis” and “null hypothesis”.

Answer 61

Hypothesis- an idea or an explanation which then needs to be confirmed through experimentation Null hypothesis- The idea that there is no significant difference between specified populations and so any observed difference would be due to chance variation in a sample

Question 62

Define the critical value

Answer 62

Critical value- A critical value is the point (or points) on the scale of the test statistic beyond which we reject the null hypothesis

Question 63

Define the test statistic

Answer 63

A test statistic is a standardized value that is calculated from sample data during a hypothesis test.

Question 64

Define p-value

Answer 64

The probability that the null hypothesis is true

Question 65

Describe when a students T-test would be used to analyse data

Answer 65

Used to compare the means of data values of two populations. | The data must be normally distributed and enough data must be collected to calculate a reliable mean.

Question 66

Describe when a Spearmen's rank correlation coefficient would be used to analyse data

Answer 66

Used to consider the relationship between two sets of data- to see if there is a correlation

Question 67

Describe when a paired t-test would be used and when an unpaired t-test would be used to analyse data.

Answer 67

Paired- to analyse the difference between the means of two data-sets where the data from both data-sets was collected from the same subject. Unpaired- where the data from both data-sets was collected from different subjects

Question 68

Describe the meaning of each of the symbols in the equation for calculating the t-value (the test statistic) from an unpaired Student’s t-test.

Answer 68

1. x̄1 -mean of sample one x̄2- mean of sample 2 2. σ1- standard deviation of sample one σ2 -standard deviation of sample two 3. n1- population of sample one, n2- population of sample two

Question 69

Describe the meaning of each of the symbols in the equation for calculating the correlation coefficient (test statistic) from a Spearman’s rank correlation.

Answer 69

1. rs= correlation coefficient 2. d= difference in ranks 3. n= number of pairs of data 4. If rs =0 there is not correlation 5. If rs<0 there is a negative correlation 6. If rs>0 there is a positive correlation

Question 70

Define the term adaptation and state 3 types of sdaptaion

Answer 70

Adaptations are characteristics that increase an organism's chance of survival and reproduction in the environment. 1. Anatomical- physical features 2. Behavioural- the ways an organism acts- inherited or learnt form parents 3. Physiological- processes that take place inside an organism

Question 71

Give 4 examples of anatomical adaptations

Answer 71

1. Body covering- hair, scales feathers- help to fly, stay warm 2. Camouflage- outer colour which allows an organisms to blend into its environment- make it harder for predators to spot. 3. Teeth- shape and type are related to an animal's diet. 4. Mimicry- copying another animals appearance or sounds allow harmless animals to fool predators into thinking it's poisonous or dangerous.

Question 72

Give 3 examples of behavioural adaptations

Answer 72

1. Survival behaviours- opossum plays dead and rabbits freeze when in danger 2. Courtship- many display elaborate behaviour to attract a mate- increases chance of reproducing. 3. Seasonal behaviours- migration and hibernation and allows animals to cope with changes in their environment.

Question 73

Give 3 examples of physiological adaptations

Answer 73

1. poison production- many reptiles produce venom to kill prey and plants to protect themselves form being eaten. 2. Antibiotic production- some bacteria produce antibiotics to kill other species of bacteria in the surrounding area 3. Water holing- store water in the body to allow it to survive in dry climates.

Question 74

Define the term analogous structure

Answer 74

Structures that have adapted to form the same function but have a different genetic origin

Question 75

Define the term convergent evolution

Answer 75

Organisms evolve similarities because the organisms adapt to similar environments or other selection pressures.

Question 76

Draw a table to compare the features of the marsupial mammalsand the placental mammals

Answer 76

Marsupial mammals- start life in the uterus, but then leave and enter the marsupium (pouch ) while they are still embryos.- moles have white-orange to match soil colour Placental mammals- Connects the embryo to it's mother's circulatory system in the uterus- reaches a high level of maturity before birth.- moles are grey to match soil 1. Example of convergent evolution, they resemble each other even though one is from australia and one from America, because they have adapted to fill similar niches 2. Have strong resemblance in overall shape, type of locomotion and feeding techniques 3. But have very different methods of reproduction

Question 77

Define the term evolution

Answer 77

The change in allele frequency within a gene pool over time

Question 78

Define the term natural selection

Answer 78

The process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes

Question 79

Define the term allele frequency

Answer 79

The relative frequency of a particular allele in a population in a given time

Question 80

Define the term gene pool

Answer 80

Sum total of all the genes in a population at a given time

Question 81

Define the term selection pressure

Answer 81

Factors that affect an organisms chance of survival or reproductive success

Question 82

Define the term selectively neutral allele

Answer 82

A variety of a gene that doesn't provide a selective advantage or disadvantage to the organism

Question 83

Define advantageous allele

Answer 83

A variety of a gene that provides a selective advantage to the organism

Question 84

Define advantageous characteristic

Answer 84

One form of a part of an organism's phenotype that provides it with a selective advantage

Question 85

Describe the steps in the process of adaptations evolving by natural selection.

Answer 85

1. Organisms within a species show variation in their characteristics that are caused by genetic variation. 2. Organisms whose characteristics are best adapted to a selection pressure- predation, competition- have an increased chance of surviving and successfully reproducing 3. Successful organisms pass the allele encoding the advantageous characteristic onto their offspring. 4. This process is repeated for every generation. Over time, the proportion of individuals with the advantageous adaptation increases. There fore the frequency of the allele that codes for this increases in the population's gene pool. 5. Over a very long periods of time this process can lead to the evolution of new species

Question 86

Explain how natural selection has resulted in the change in frequency of dark and pale moths in populations of the peppered moth (Biston bettularia) near industrial towns and cities over time.

Answer 86

1. In industrial revolution trees became darker and so the dark moths were better adapted, so more survived etc. frequency of the dark allele increased 2. Now trees are lighter the frequency of the pale allele in the moth gene pool has increased

Question 87

Describe how human activity has resulted in evolution in populations of the bacterium Staphylococcus aureus, the Sheep blowfly Lucilia cuprina, and the bacterium Flavobacterium.

Answer 87

1. Sheep blowflies- laid eggs in sheep's tails, pesticide was introduced and they became resistant to it 2. Bacterium- a strain of bacteria which have evolved to digest nylon and live in waste water form factoids that produce nylon. 3. Staphylococcus aureus- has developed resistance to many antibiotics. when exposed resistant individuals survived etc.