Classification and Evolution

Question 1

What is phylogenetic classification?

Answer 1

It is a type of classification that arranges species into groups according to their evolutionary origins and relationships. Tells us how closely related species are and how recent their shared common ancestors are.

Question 2

What is the binomial naming system and why is it used?

Answer 2

The genus and species of an organism being used to identify it. It is universal as it is in latin. Common names are misleading because they are different in every languge and often originate from the appearance of the organism which can be inaccurate.
-binomial is universal, no confusion
-Binomial naming indicates how closely related species are.

Question 3

What are the 5 kingdoms in classification?

Answer 3

1.Anamalia
2.Fungi
3.Plantae
4.Protoctista
5.Prokaryotae

Question 4

Describe the Kingdom Prokaryotae

Answer 4

• Unicellular, no membrane bound organelles, small ribosomes, a ring of Dna with no associated proteins.
  -No feeding system, absorbs nutrients across its surface or photosynthesis

Question 5

Describe the Kingdom Protoctista

Answer 5

Unicellular, has membrane bound organelles, sometimes chloroplasts, cilia or flagella for movement.
Nutrients absorbed by photosynthesis, ingestion of other organisms or some are parasites.

Question 6

Describe the kingdom Fungi

Answer 6

Can be uni or multicellular, have a nucleus and membrane bound organelles, no chloroplasts, cannot move and body is made of threads of hyphae.
Nutrients absorbed from dead and decaying matter (SAPROBIONTS). Food can be stored as glycogen.

Question 7

Describe the Kingdom Plantae

Answer 7

Multicellular, have nucleus and membrane bound organelles, have chloroplasts and don’t move.
Nutrients absorbed by photosynthesis and food stored as starch.

Question 8

Describe the Kingdom Anamalia

Answer 8

Multicellula, have a nucleus and membrane bound organelles, no chloroplasts and can move using cilia, flagella or muscles.
Nutrients absorbed by ingestion and stored and glycogen.

Question 9

Why was the old method of classification inaccurate?

Answer 9

Classification used to be based on observable characteristics. This is misleading - same species can look different if their habitats have different environmental conditions.
- members of different species can look similar is they share a habitat/similar environmental conditions (CONVERGENT EVOLUTION)

Question 10

How did the accuracy of classification improve?

Answer 10

Due to advances in genome sequencing and immunology to compare mlecular differences.

Question 11

Explain how comparing DNA base sequences aids in classification.

Answer 11

DNA base sequence of organisms for common genes are compared. Closely related = higher degree of similarity. This is because mutations accumulate over time, so they must have evolved from a closer common ancestor and had less time to accumulate different mutations resulting in more different DNA base sequence.

Question 12

Explain how the seqeunce of amino acids aids in classification.

Answer 12

The sequence of AA in a polypeptide chain can be compared because it is determined the DNA base sequence (which is degenerate). The method won’t be as accurate because some of these AA could be coded for by different codons.

Question 13

What are the 3 domains?

Answer 13

Bacteria, eukaryota and Archaea.
As a result, there are actually 6 Kingdoms - Prokaryota is split into eubacteria (true bacteria) and archaebacteria

Question 14

Where are archaebacteria found?

Answer 14

Living in extremem environments like thermal hotsprings and anaerobic environments.

Question 15

What is natural selection?

Answer 15

The process by which evolution occurs. Initially proposed by Wallace then submitted to Darwin to be peer reviewed.
Darwin conducted his own research (finches on Galapogos Island) until he independently published.

Question 16

What is the evidence of evolution?

Answer 16

Fossils, DNA and molecular evidence

Question 17

What are fossils and how do they prove evolution?

Answer 17

They are imprints, remains of dead animals and plants in rocks from a long time ago. They provide evidence of how species have changed and evolved over time. They show how species were more simple man many years ago

Question 18

How does DNA base sequence of common genes provide evidence of natural selection and evolution?

Answer 18

This or other molecular evidence (eg RNA and AA sequences) can be used to examine how closely related different species are. Scientists can estimate the point in history where they shared a common ancestor.
-Cytochrome C is a protein found in mitochondria which many species have. This is often what is compared.

Question 19

What is an anatomical adaptation?

Answer 19

Internal or external physical featuresW

Question 20

What are behavioural adaptations?

Answer 20

Changes in the way organisms act. These can be genetic in cause or learned from parents.

Question 21

What are physiological adaptations?

Answer 21

Processes that take place within an organism

Question 22

Why do organisms from different taxonomic groups have similar anatomical adaptations?

Answer 22

Due to convergent evolution where species are exposed to similar selection pressures resulting in them undergoing natural selection for similar alleles that mean they become more genetically and phenotypically similar.

Question 23

What is interspecific variation?

Answer 23

Differences between members of different species.
Eg, number og legs, fur, hair, feeding mechanisms.

Question 24

What isintraspecific variation?

Answer 24

Differences between members of the same species. Introduced through mutations, crossing over and independent assortment (sexual reproduction, meiosis, random fertilisation)

Question 25

Why do environmental factors have a greater impact on variation in plants?

Answer 25

They cannot move so are always exposed to environmental conditions and undergo abiotic selection pressures (e.g precipitation, wind, sunlight and nutrients available in the soil)

Question 26

What is continuous variation?

Answer 26

Traits that are controlled by many genes and the environment can have an impact. Graphically represented using a histogram

Question 27

What is discontinuous variation?

Answer 27

Traits controlled by a single gene, environment have no impact so individuals fit into a particular category. Bar chart. Eg blood group

Question 28

What is natural selection?

Answer 28

The process that leads to evolution. It results in an increase in the number of beneficial alleles in a population due to selection pressure. This results in species becoming better adapted to their environment.

Question 29

What is evolution?

Answer 29

The change in allele frequency over many generations in a population

Question 30

Explain the process of natural selection.

Answer 30

1.New alleles for gene created by random mutation.
2. If the new alleles increase chances of individual surviving that environment, they are more likely to survive and reproduce.
3. This passes on the advantageous allele to the next generation.
4. Over many generations, the new allele increases in frequency in the population as others die out.

Question 31

What is mean?

Answer 31

Sum of all samples divided by number of samples.

Question 32

What is mode?

Answer 32

Most common number?

Question 33

What is median?

Answer 33

Number in the middle in a set of ordered values.

Question 34

What is standard deviation and when is it used?

Answer 34

Measures the spread of data around the mean value. The extremes are excluded.
S= sample standard deviation
x= observation/value
x- = mean
n= sample size/ number of values

Question 35

Why are standard deviation important?

Answer 35

They are a good indicator to whether there is a difference or not between means of different groups. Overlapping = no significant difference as range overlaps.

Question 36

Why do we use statistical tests?

Answer 36

Standard deviations cannot actually tell you if there is a difference between your groups.

Question 37

What is chi squared and when is it used?

Answer 37

For differences in categoric data, ratio, observed and expected values

P value < 0.05 = some significant difference.
“There is less that 5% probability that the difference/relationship is due to chance”

Question 38

What are t tests and when are they used?

Answer 38

They are a statistical test to tell you if the difference in means of 2 groups is significant. It is used to compare the means of TWO SEPARATE SETS OF DATA.
Unpaired - both sets of data from 2 separate groups
Paired - both means from the same group of people at different points in time.

P value < 0.05 = some significant difference.
“There is less that 5% probability that the difference/relationship is due to chance”

Question 39

What is spearman’s rank correlation and when is it used?

Answer 39

It is a correlation coefficient and is used when you are checking for a relationship between 2 variables. This is usually plotted as a scatter graph.
P value < 0.05 = some significant difference.
“There is less that 5% probability that the difference/relationship is due to chance”