4.2.2 - Classification and evolution

Question 1

Define the term ‘classification’ ?

Answer 1

Classification : The process by which living organisms are sorted into groups based on similar characteristics

Question 2

Define the term ‘species’ ?

Answer 2

Species - A group of organisms that able to reproduce to produce fertile offspring

Question 3

What is the taxonomic hierarchy ?

Answer 3

• Domain
• Kingdom
• Phylum
• Class
• Order
• Familly
• Genus
• Species

Question 4

What is the binomial naming system ?

Answer 4

It is a universal naming system where all species are given a scientific name consisting of two parts ( the first part is the genus, the second part is the species )

Question 5

What are the benefits of the binomial naming system ?

Answer 5

• Different areas/ countries use different names
• It is a universal naming system that prevents confusion regarding a particular group of orgasnims

Question 6

What are the three different domains ?

Answer 6

• Bacteria (prokaryotes)
• Archaea (prokaryotes)
• Eukarya (eukaryotes)

Question 7

What are the two different types of cells ?

Answer 7

• Eukaryotes
• Prokaryotes

Question 8

What are features of bacteria ?

Answer 8

• Prokaryotic cells
• Contain no nucleus
• Bacterial cells divide by binary fission

Question 9

What are the features of archaea ?

Answer 9

• Prokaryotic cells
• Contain no nucleus
• Unique lipids being found in the membranes of their cells
• No peptidoglycan in their cell walls
• Unique ribosomal structure

Question 10

What are the main differences between archaea and bacteria ?

Answer 10

• Membrane lipids
• Ribosomal RNA
• Cell wall composition

Question 11

Explain how archaea and bacteria differ regarding membrane lipids ?

Answer 11

• The membrane lipids of Archaea consist of branched hydrocarbon chains bonded to glycerol by ETHER linkages
• The membrane lipids of Bacteria consist of unbranched hydrocarbon chains bonded to glycerol by ester linkages

Question 12

Explain how archaea and bacteria differ regarding ribosomal RNA ?

Answer 12

• Both Archaea and Bacteria possess 70S ribosomes
• Archaea 70s ribosomes possess a smaller subunit that is more similar to the subunit in Eukaryotic ribosomes than subunits in Bacterial ribosomes

Question 13

Explain how archaea and bacteria differ regarding cell wall composition ?

Answer 13

• Archae cell walls do not contain peptidoglycan
• Bacteria cell walls contain peptidoglycan

Question 14

What are the features of eukarya ?

Answer 14

• Eukaryotic cells
• Contain nucleus and membrane-bound organelles
• Eukaryotic cells divide by mitosis
• Eukaryotes can reproduce sexually or asexually

Question 15

What are the differences between eubacteria and archaebacteria ?

Answer 15

• Eubacteria are fund everywhere and most bacteria are within this kingdom
• Archaebacteria live in extreme environments such as thermal hot springs/ anaerobic environments

Question 16

Compare features of archea, bacteria and eukarya ?

Answer 16

Question 17

What are the five kingdoms ?

Answer 17

• Prokaryota
• Protoctista
• Fungi
• Plantae
• Animalia

Question 18

What are the features of Prokaryota ?

Answer 18

• Mostly unicellular
• Cell wall made of peptidoglycan
• No nucleus / mitochondria / membrane-bound organelles
• A ring of DNA with no associated proteins
• Some have flagella
• Autotrophic / heterotrophic

Question 19

Features of Protoctista ?

Answer 19

• Eukaryotic
• Unicellular and multicellular
• No cell wall/ sometimes contain cell wall made of cellulose and chloroplasts
• Contain nucleus, other membrane-bound organelles
• Some have flagella or cilia
• Autotrophic/ heterotrophic

Question 20

What are autotrophic feeders ?

Answer 20

Organisms that are feed by produce food via photosynthesis/ photosynthetic organisms

Question 21

What are heterotrophic feeders ?

Answer 21

Organisms that feed by decomposing living or dead organic materials

Question 22

Features of fungi ?

Answer 22

• Eukaryotic
• Unicellular/ multicellular
• Cell wall made of chitin
• Contain nucleus, other membrane-bound organelles
• No cilia
• Some consist of long threads of hyphae that form a network of filaments called the mycelium
• Heterotrophs
• Reproduce using spores that disperse nearby

Question 23

Features of plantae ?

Answer 23

• Eukaryotic
• Multicellular
• Cell wall made of cellulose
• Contain nucleus/ membrane-bound organelles
• Contain chloroplasts
• Sometimes contain flagella
• Autotrophs

Question 24

Features of animalia ?

Answer 24

• Eukaryotic
• Multicellular
• No cell wall
• Contain nucleus, other membrane-bound organelles
• Sometimes contain cilia
• Heterotrophs

Question 25

Name examples of five kingdoms ?

Answer 25

- Prokaryota : bacteria, cyanobacteria - Protoctista : amoeba, algae - Fungi : yeast, aspergillus - Plantae : conifers, ferns - Animalia : jellyfish, worms

Question 26

Compare the five kingdoms based on, type of body, nuclear envelope, cell wall, cell vacuole, organelles and fibres, type of nutrition, mobility, nervous coordination and examples ?

Answer 26

Question 27

How have there been changes in the classification system ?

Answer 27

- Originally, organisms were classified based on observable characteristics ( artificial classification ) - Now, organisms are classified on the basis of phylogeny due to advances in DNA, RNA and protein sequencing

Question 28

Define the term 'phylogenetics' ?

Answer 28

Phylogenetics : The study of the evolutionary relationships between organisms

Question 29

What are the three types of data used to investigate evolutionary relationships ?

Answer 29

- DNA - mRNA - Amino acids (of a protein)

Question 30

Explain how DNA is used to study evolutionary relationships between organisms ?

Answer 30

- DNA base sequence of a common gene is compared between two different species - The more similar the DNA base sequence, the more closely related the species - Likely, they evolved from/ share a recent common ancestor

Question 31

Explain how amino acids of a protein are used to study evolutionary relationships between organisms ?

Answer 31

- The amino acid sequence for a specific protein is compared between two individuals - Commonly, Cytochrome c is used as it is an integral protein to respiration used by all eukaryotic organisms - The more similar the sequences, the more closely related the species

Question 32

Why is comparison of amino acid sequence less accurate than DNA base sequence ?

Answer 32

- Code is degenerate and multiple triplets/ codons will code for the same amino acids - Therefore amino acid sequence does not always determine the DAN base sequence

Question 33

What is a phylogenic tree ?

Answer 33

A diagram used to represent the evolutionary relationships between organisms

Question 34

What are features of a phylogenetic tree ?

Answer 34

- The closer the branches, the closer the evolutionary relationship - The root is the common ancestor of the tree - The node shows the common ancestor of those descendants - The tips represent the descendant taxa/ species

Question 35

Explain how using the study of evolutionary relationships to classify organisms is advantageous to phylogenetic system ?

Answer 35

- Organisms are classified based on a common ancestor/ genotype instead of observable characteristics/ phenotype - This is more accurate/ phylogeny is more accurate than artificial classification

Question 36

Define the term ' Evolution' ?

Answer 36

Evolution : The gradual change in the characteristics of a species over time as a result of natural selection

Question 37

What two scientists contributes to the theory of evolution by natural selection ?

Answer 37

- Charles Darwin - Russel Wallace

Question 38

Explain how Charles Darwin produces the theory of evolution ?

Answer 38

- He made observations of finches and noticed different islands had different finches - Finches beaks and claws were different shapes and sizes - Finches with beaks better suited to environment/ meaning they are more likely to survive, reproduce and pass on their characteristics to offspring resulting in species characteristics changing over time due to natural selection

Question 39

How did Russel Wallace contribute to the theory of natural selection ?

Answer 39

- He had similar ideas to Charles Darwin - They both met and published their paper on natural selection together - He increased weight of evidence of natural selection

Question 40

What are the key sources of evidence f to her theory of evolution by natural selection ?

Answer 40

- Fossil evidence ( fossil records/ fossils ) - Molecular evidence ( DNA )

Question 41

What are fossils ?

Answer 41

The preserved remains and traces of organisms from a past geological age

Question 42

Explain how fossils/ fossil records serve as a source of evidence for the theory of evolution by natural selection ?

Answer 42

- Fossils can be dated and sequences from oldest to youngest - This shows how organisms change over time / evolved - This provides evidence for the gradual change from simple life forms ( Archaea and Bacteria ) to complex Eukaryotic life forms and evolutionary relationships between organisms - This shows similarities between different species

Question 43

Define the term 'variation' ?

Answer 43

Variation : The differences in characteristics between living organisms

Question 44

What are the different types of variation ?

Answer 44

- Interspecific variation - Intraspecific variation - Discontinuous variation - Continuous variation

Question 45

Define the term 'Interspecific variation' ?

Answer 45

Interspecific variation : The differences between living organisms of different species

Question 46

Define the term 'Intraspecific variation' ?

Answer 46

Intraspecific variation : The differences between living organisms within the same species

Question 47

Define 'Discontinuous variation' ?

Answer 47

Discontinuous variation : The differences that fall into discrete and distinguishable categories with no intermediates

Question 48

Define 'Continuous variation' ?

Answer 48

Continous variation : The differences that show a range of values and can fall anywhere between two extremes

Question 49

Name examples of discontinuous and continuous variation ?

Answer 49

- Discontinuous : Blood groups, Sex, Eye colour Continuous : Body mass, Height, Shoe size

Question 50

How is discontinuous and continuous variation represented ?

Answer 50

- Discontinuous : Bar charts - Continuous : Bell-shaped curve/ histogram

Question 51

What causes discontinuous and continuous variation ?

Answer 51

- Discontinuous : Solely determined by genotype, controlled by one or two genes - Continuous : Determined by environmental factors and genotype, controlled by multiple genes

Question 52

What is the equation for the standard deviation ?

Answer 52

Question 53

What does the standard deviation show ?

Answer 53

Standard deviation measures the spread of data around the mean value

Question 54

What is the equation for a t-test ?

Answer 54

Question 55

What are the two types of t-tests ?

Answer 55

- Unpaired t-test - Paired t-test

Question 56

What is a unpaired and paired t-test used for ?

Answer 56

- Unpaired t-test compares the means of two different data sets - Paired t-test compares the means of the same dat set at different times/ conditions

Question 57

What is the equation for the degrees of freedom in a t-test ?

Answer 57

Question 58

Explain how to determine whether the difference between tow data sets if statistically significant ?

Answer 58

- If the t value is greater than the critical value then any difference between the means of the two data sets is said to be statistically significant - There is a less than 5 % probability that any difference is due to chance - The null hypothesis can be rejected