MODULE 4 - classification and evolution Flashcards

Question

how can scientists achieve a more accurate estimate of evolutionary relatedness?

Answer 1

Looking at multiple proteins or multiple regions of the genome - will choose specific proteins or sections of the genome for comparison between organisms

Answer 2

the protein needs to be present in a wide range of organisms and show sufficient variation between species

Answer 3

it is an integral protein to respiration (in the electron transport chain) which is used by all eukaryotic organisms meaning it is present in a wide range of organisms

Answer 4

the sequences of DNA bases, mRNA bases and amino acids are more similar

Answer 5

- will have separated into separate species more recently than two groups with less similarity in their sequences - closely related

Answer 6

they have been separated for longer have had a greater amount of time to accumulate mutations and changes to their DNA,mRNA and amino acid sequences

Answer 7

Sequence analysis and comparison

Answer 8

- DNA is extracted from the nuclei of cells taken from an organism - The extracted DNA is processed, analysed and the base sequence is obtained - The base sequence is compared to that of other organisms to determine evolutionary relationships

Answer 9

the way in which species have changed over time and continue to change

Answer 10

- All organisms produce more offspring than could ever actually survive - intraspecific variation - Offspring inherit characteristics from their parents

Answer 11

Fossil evidence Molecular evidence evolutionary embryology

Answer 12

- simpler life forms found in older/deeper rock - the physical anatomy of fossils can be compared and studied - can compare fossils to living organisms

Answer 13

it is incomplete: not all fossils have been discovered + some may have been destroyed e.g. by volcanoes

Answer 14

a stricture in different species that seems superficially different but shares a similar underlying anatomy and developmental origin - same underlying structure

Answer 15

divergent evolution

Answer 16

when closely related species, sharing a common ancestor, gradually develop different traits and characteristics due to adapting to different environments or ecological niches, often leading to new species (speciation) over time

Answer 17

using comparative biochemistry

Answer 18

the study of similarities snd differences in the proteins and other molecules that control life processes

Answer 19

- the molecular sequence of cytochrome C and rRNA (two highly conserved molecules) can be compared by looking at the order of DNA bases/amino acids in a protein

Answer 20

- the study of embryos - embryos being very similar implies that animals develop in a similar way and that the processes of embryonic development have a common origin

Answer 21

- intraspecific - interspecific

Answer 22

the differences between organisms of the same species

Answer 23

the differences between organisms of different species

Answer 24

- genetic - environmental

Answer 25

natural selection to occur

Answer 26

differences that fall into discrete and distinguishable categories with no intermediates - cannot be measured over a range

Answer 27

using a bar chart

Answer 28

differences that show a range of values and can fall anywhere between two extremes

Answer 29

on a histogram with bars that touch each other, and will often show a characteristic bell-shaped curve

Answer 30

- solely due to genetic factors: phenotype = genotype -- Different genes have different effects on the phenotype -- Different alleles at a single gene locus have a large effect on the phenotype

Answer 31

- caused by an interaction between genetics and the environment: Phenotype = genotype + environment - Different alleles at a single locus have a small effect on the phenotype - Different genes can have the same effect on the phenotype and these add together to have an additive effect

Answer 32

- apply in continuous variation - they are a large number of genes that have a combined effect on the phenotype

Answer 33

they can affect how organisms grow and develop

Answer 34

- An accident may lead to scarring on the body - Eating too much and not leading an active lifestyle will cause weight gain - Being raised in a certain country will cause you to speak a certain language with a certain accent

Answer 35

- allele variation - mutations - meiosis: indépendant assortment and crossing over - random fertilisation - sexual reproduction: the offspring inherits random genes from each parent

Answer 36

- physiological - anatomical - behavioural

Answer 37

anatomical

Answer 38

physiological

Answer 39

behavioural

Answer 40

body covering camouflage teeth mimicry

Answer 41

a thick waxy cuticle sunken stomata curled leaves hairy leaves

Answer 42

- innate - instinctive - learned

Answer 43

survival behaviours e.g. playing dead courtship seasonal behaviours e.g. migration + hibernation

Answer 44

poison production antibiotic production water holding

Answer 45

how organisms from different taxonomic groups may show similar adaptations even though they do not share a recent common ancestor

Answer 46

- two species live in different parts of the world with similar environments - the species deal with the same selection pressures - the same characteristics are advantageous in the two environments, so individuals with these characteristics are more likely to survive and reproduce - over time the advantageous characteristics become widespread in both populations

Answer 47

structures which have adapted to perform the same function but have a different genetic origin

Answer 48

- marsupial and placental mice - flying squirrels and flying phalangers - marsupial and placental moles

Answer 49

aloe and agave as they have both had to survive in the desert

Answer 50

differences in DNA base sequences between individual organisms within a species population

Answer 51

Differences in the alleles possessed by individuals within a population result in differences in phenotypes Some phenotypes may be advantageous, disadvantageous or neutral, compared to other phenotypes

Answer 52

they increase the chance of individuals with a specific (more advantageous) phenotype surviving and reproducing over others

Answer 53

as having a higher fitness

Answer 54

The fitness of an organism is defined as its ability to survive and pass on its alleles to offspring

Answer 55

populations with a large gene pool or high genetic diversity

Answer 56

they are much less able to adapt to changes in the environment and so can become vulnerable to extinction

Answer 57

they act as selection pressures

Answer 58

when there are no environmental factors or population checks acting on the population

Answer 59

--> Random mutation can produce new alleles of a gene --> Many mutations are harmful or neutral but, under certain environmental conditions, the new alleles may benefit their possessor, leading to an increased chance of survival and increased reproductive success --> The advantageous allele is passed onto the next generation --> As a result, over several generations, the new allele will increase in frequency in the population

Answer 60

chemical substances that inhibit or kill bacterial cells with little or no harm to human tissue

Answer 61

- variation causes mutations - A chance mutation might cause some bacteria to become resistant to an antibiotic - When the population is treated with this antibiotic, the resistant bacteria do not die - the resistant bacteria can continue to reproduce with less competition from the non-resistant bacteria, which are now dead - Therefore the genes for antibiotic resistance are passed on with a much greater frequency to the next generation - Over time, the whole population of bacteria becomes antibiotic-resistant because the antibiotic-resistant bacteria are best suited to their environment

Answer 62

evolution by natural selection

Answer 63

Vertical transmission Horizontal transmission

Answer 64

--> Bacteria reproduce asexually by binary fission (the DNA of the bacterial chromosome is replicated and the bacterial cell divides in two, with each daughter cell receiving a copy of the chromosome) --> Bacteria reproduce like this very rapidly (on average, every 20 minutes) --> If one bacterium contains a mutant gene that gives it antibiotic resistance, all of its descendants (millions of which can be produced in a matter of hours) will also have the antibiotic resistance --> This form of transmission enables antibiotic resistance to spread within a bacterial population

Answer 65

--> Plasmids (the small rings of DNA present in bacterial cells) often contain antibiotic-resistant genes --> These plasmids are frequently transferred between bacteria (even from one species to another) --> This occurs during conjugation (when a thin tube forms between two bacteria to allow the exchange of DNA) – DNA from the bacterial chromosome can also be transferred in this way --> In this way, a bacterium containing a mutant gene that gives it antibiotic resistance could pass this gene on to other bacteria (even those from a different species). This is how ‘superbugs’ with multiple resistance have developed (e.g. methicillin-resistant Staphylococcus aureus – MRSA) --> This form of transmission enables antibiotic resistance to spread within or between bacterial populations

Answer 66

the overuse of antibiotics in situations where they were not really necessary or the incorrect use of antibiotics, for example: - For treatment of non-serious infections - Routine treatment of animals in agriculture - Failure to finish the prescribed course of antibiotics

Answer 67

- Only prescribing antibiotics when absolutely necessary - Ensure patients complete courses of antibiotics - Rotate which antibiotics are used so that one type is not continuously used in the treatment of a specific disease - Hold back some antibiotics from being used at all so they are available as a 'last resort' - More investment in research into new antibiotics - Tighter controls in countries in which antibiotics are sold without a doctor’s prescription - Antibiotics not being used for viral infections

Answer 68

By using antibiotics frequently

Answer 69

- finding new antibiotics that bacteria haven't been exposed to yet is expensive and time-consuming - Some strains of bacteria can be resistant to multiple antibiotics - Commonly prescribed antibiotics are becoming less effective

Answer 70

-- Ensuring good hygiene practices such as handwashing and the use of hand sanitisers (this has reduced the rates of resistant strains of bacteria, such as MRSA, in hospitals) -- Isolating infected patients to prevent the spread of resistant strains, in particular in surgical wards where MRSA can infect surgical wounds

Answer 71

it measures the spread of data around the mean value

Answer 72

when comparing consistency between different data sets

Answer 73

to compare the means of two sets of data and determine whether they are significantly different or not

Answer 74

a statement of what we would expect if there is no significant difference between two means, and that any differences seen are due to chance

Answer 75

If there is a statistically significant difference between the means of two sets of data, therefore the observation is not down to chance

Answer 76

v = (n1 - 1) + (n2 - 1)

Answer 77

that 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

Answer 78

there is no significant difference between the means of the two data sets The probability that any difference is due to chance is higher than 5 % The null hypothesis is accepted

Answer 79

Step 1: calculate the mean for each data set Step 2: calculate the standard deviation (s) for each data set Steps 3-5: use the standard deviations to complete the t test Step 6: calculate the degrees of freedom (v) for the data Step 7: determine where the t value lies in relation to values in a critical values table Step 8: draw a conclusion

Answer 80

we select the value that is both in line with our degrees of freedom value and is at a probability level of 0.05 (In biology we are looking for a less than 5 % probability)

Answer 81

when determining whether there is correlation between variables that don’t show a normal distribution

Answer 82

Step 1: Rank each set of data (rank 1 being the smallest data figure) Step 2: Find the difference in rank between the two species, D Step 3: Square the difference in rank, D2 Step 4: Substitute the appropriate numbers into the equation Step 5: Refer to a table that relates values of rs to probability. Look for the 0.05 probability level with n = 10 - a null hypothesis must be stated

Answer 83

rs = spearman’s rank coefficient D = difference in rank n = number of samples

Answer 84

If the value calculated for Spearman’s rank is greater than the critical value for the number of samples in the data ( n ) at the 0.05 probability level (p), then the null hypothesis can be rejected, meaning there is a correlation between two variables

Answer 85

If the value calculated for Spearman’s rank is greater than the critical value for the number of samples in the data ( n ) at the 0.05 probability level (p)

MODULE 4 - classification and evolution Flashcards

(109 cards)