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ABHAYS A-LEVEL BIO FLASHCARDS > M4, C10 Classification and Evolution > Flashcards

M4, C10 Classification and Evolution Flashcards

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Biology 101 flashcards
1
Q

what would scientists look at when they discover a new organism in order to group it

A 
Physical characteristics
Behaviour
DNA
Mating/reproductive methods
Cell structure
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2
Q

why do we need a single system to classify organisms

A

allows us to identify new species
allows scientists worldwide to share research and link organisms from different countries
allows us to find evolutionary links and find a common ancestor of species
to predict characteristics

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3
Q

what is the order of the taxonomic groups

A 
kingdom
phylum
class
order
family
genus
species
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4
Q

what is the taxonomic group above kingdom

A

domain

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5
Q

what are the 3 domains

A

bacteria
archaea
eukarya

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6
Q

define species

A

a group of organisms that are able to reproduce fertile offspring

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7
Q

why could an offspring be infertile when 2 different species reproduce

A

it has an odd number of chromosomes so during gamete production homologous pairing of chromosomes will not occur properly in prophase I of meiosis I

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8
Q

what are the rules for naming organisms

A

called binomial nomenclature
first word - genus, first letter is capital
second word - species, all lower case
whole name in italics or underlined because it si hard to handwrite in italics

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9
Q

name a lion
species is leo
genus is panthera

A

Panthera leo

in italics or underlined

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10
Q

how were organisms first classified under arstotle’s theory

A

he thought every organism could be put into 2 kingdoms: plants and animals

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11
Q

In the old system of classification there were just 5 kingdoms what where they

A 
prokaryotae
protoctista
fungi
plantae
animalia

(people find purple plants attractive)

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12
Q

what are the features of the kingdom prokaryotae

A

unicellular
no nucleus or other membrane bound organelles
ring of naked DNA - small ribosomes
no visible feeding mechanism - nutrients absorbed by cell wall or produced internally by photosynthesis

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13
Q

give examples of organisms in the kingdom prokaryotae

A

bacteria - E. coli

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14
Q

what are the features of the kingdom protoctista

A

mainly unicellular
has a nucleus and membrane bound organelles
some have chloroplasts
some are immobile but others move by cilia, flagella or amoeboid mechanism

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15
Q

give examples of protocitsta

A

malaria

potato/tomato blight

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16
Q

what are the features of the kingdom fungi

A 
unicellular or multi-cellular
nucleus and membrane bound organelles
cell wall made of chitin
no chloroplasts or chlorophyll
no mechanisms for locomotion
most have a body made of threads of hyphae
saprophytic feeders - nutrients acquired by absorption
most store food as glycogen
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17
Q

give examples of fungi

A

ringworm
Black sigatoka
Athletes foot

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18
Q

what are the features of the kingdom plantae

A

multi-cellular
membrane bound organelles including nucleus, cellulose cell wall
all contain chlorophyll
most don’t move but some gametes move using cilia or flagella
autotrophic - nutrients acquired by photosynthesis so make their own food
store food as starch

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19
Q

what are the features of the kingdom animalia

A

multi-cellular
nucleus and membrane bound organelles (no cell walls)
no chloroplasts
move with cilia, flagella or contractile proteins sometimes in form of muscular organs
heterotrophic - nutrients acquired by ingestion
food stored as glycogen

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20
Q

what have been the recent changes to the classification system

A

Classification used to be based on observable features

Due to advances in genetics we can now study the evolutionary relationship between organisms

When organism evolve so does their DNA, and as DNA determines proteins it in turn determines characteristics

So, for characteristics to change so does DNA

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21
Q

give an example of how the classification system has changed in terms of haemoglobin

A

Haemoglobin is a protein with 4 polypeptide chains made of a fixed number of amino acids
in chimps, their haemoglobin differs by 1 amino acid
the structure of haemoglobin is very similar meaning we must have a common ancestor

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22
Q

what features were used to distinguish the 6th kingdom

A 
ribosomal RNA (rRNA) and 
the cell’ membrane lipid structure 
Sensitivity to antibiotics
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23
Q

what is the 3 domain, 6 kingdom classification system

A

3 domains - bacteria, archaea and eukarya
6kingdoms - eubacteria, archaebacteria, protoctista, plantae, fungi and animalia

(the prokaryotae group has been split into 2)

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24
Q

what are the differences and similarities between archaebacteria and eubacteria

A

archaebacteria can be found in extreme conditions, eubacteria found in all environments

eubacteria contains peptidoglycan in the cell wall whereas archaebacteria don’t

Archaebacteria how 5 polypeptides in their RNA polymerase structure whereas Eubacteria have 8-12 polypeptides in their RNA polymerase structure.

both single celled prokaryotes

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25
Q

define phylogeny

A

The study of the closeness of evolutionary relationships between organisms

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26
Q

what are phylogentic trees and how do you draw them

A

Diagram to show the evolutionary relationships between organisms.

Older species are found further down the tree, recent species nearer to the top

The closer the branches are, the more closely related the organism are.

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27
Q

why is phylogeny better than linnaean classification

A

The Linnaean classification system is based purely on observable features.

Phylogeny produces a continuous tree, and organisms can be placed anywhere along it, they do not have to fit into discrete groups

The Linnaean system does not tell you anything about the number of different species or level of diversity or how long the groups have been around

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28
Q

what were Darwin’s observations

A

Organisms produce more offspring than survive
There’s variation in the characteristics of members of the same species
Some of these characteristics can be passed on from one generation to the next
Individuals that are best adapted to their environment are more likely to survive

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29
Q

what is the evidence for evolution

A

palaeontology
comparative anatomy
comparative biochemistry

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30
Q

what did Lyell discover

A

fossils are evidence of animals that lived millions of years agoo

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31
Q

what did Hutton propose

A

principle of uniformitarianism

32
Q

what did Wallace propose

A

theory of evolution by natural selection

33
Q

How do fossils support the theory of evolution [3]

A

fossils show that organisms have changed over time;

idea that fossils or rocks can be dated ;

idea of fossils showing intermediate forms / sequences e.g general trend from, small / simple, to, large / complex;

34
Q

why is the fossil record incomplete

A

soft bodied organisms decompose
destroyed in earthquakes or volcanoes
undiscovered

35
Q

what is comparative anatomy

A

study of similarities and differences in the anatomy of different living species

36
Q

what is a homologous structure

A

a structure that appears superficially different in different organisms but has the same underlying structure

37
Q

how does comparative anatomy provide evidence for evolution

A

vertebrate limbs are all very similar in structure but have different functions
this shows they all must have had a common ancestor

38
Q

what is divergent evolution

A

from a common ancestor, different species have evolved

occurs when closely related organisms diversify to adapt to new habitats as a result of migration or loss of habitat

39
Q

define evolution

A

the slow and continual change of organisms from one generation to the next

40
Q

what is comparative biochemistry

A

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

41
Q

what are the two most common molecules used in comparative biochemistry and why

A

cytochrome c
ribosomal RNA

Changes to the structure don’t affect the function so natural selection wouldn’t have changed these molecules.

42
Q

what is interspecific variation

A

Variation between members of different species.

43
Q

what is intraspecific variation

A

Variation between members of the same species.

44
Q

what causes variation

A

genetics
environment
or both

45
Q

give an example of a human characteristic with variation caused by:

a) environment
b) genetics
c) both

A

a) scar
b) blood group
c) height

46
Q

what causes genetic variation

A

alleles
mutations
meiosis
sexual reproduction

47
Q

how do alleles cause genetic variation

A

different alleles produce different effects
different combinations are formed from parents
so different organisms in a species have different alleles

48
Q

how do mutations cause genetic variation

A

changes made to DNA sequence so proteins are changed
this affects physical and metabolic characteristics
if a mutatio occurs in gametes then it’s passed onto offspring

49
Q

what are the two types of meiosis

how do they causes genetic variation

A

independent assortment and crossing over

gametes are produced by meiosis
each gamete receives half the genetic content of the parent cell
before nucleus divides, the genetic material mixes up

50
Q

how does sexual reproduction cause genetic variation

A

genes are inherited from two parents and it’s random

51
Q

what is discontinuous variation

how is it represented

A

a characteristic that can only result in certain values
there are no in-between values

normally represented using a bar chart or pie chart

52
Q

what is continuous variation

A

a characteristic that can take any value within a range

data collected in frequency table and plotted on a histogram or graph

53
Q

what are the characteristics of a normal distribution curve

A

the mean, median and mode are the same
it is bell-shaped which is symmetrical about the mean
50% of values are less than the mean and 50% are greater
most values lie close to the mean value

54
Q

what is standard deviation

what does it mean when it is large

A

measure of how spread out the data is

the greater the sd, the greater the spread of data which means a higher variation

55
Q

how do you work out standard deviation the long way?

A 
work out the mean
minus the mean from each value
square these values
add them all up
divide that number by the (sample size - 1)
square root
56
Q

What is the Student t-test used for

A

Compares the mean value for two sets of data

Checks whether there’s a significant difference between the mean values or whether the difference is just down to chance

57
Q

Look at the Student t test equation

What do they all stand for

A 
Mean population 1
Mean population 2
S1 - standard deviation population 1 
S2 - standard deviation population 2
N1 - total number of samples pop 1
N2 - total number of samples pop 2
58
Q

What is the equation for degrees of freedom

A

Df = n1 + n2 - 2

59
Q

How do you use a significance table

A

What out the degrees of freedom for the left hand side

Go along to 5%

60
Q

From the significance table, what do the results tell you

A

If the t value is less than the stated value, then there’s no significant difference between the mean results

If the t value is greater than the stated value then there is a significant difference

61
Q

What is null hypothesis

A

Always suggests there will be no correlation between the factors you’re investigating

We have to say whether we accept or reject null hypothesis based on results in a t test or correlation coefficient

If results aren’t statically significant it means the correlation could be down to chance

62
Q

What does the correlation coefficient show

A

The test considers how closely related two sets of data are

63
Q

How do you work out the correlation coefficient

A

Rank from lowest to highest
Work out d which is R1 - R2
Square the answers
Add them up to the sum of d^2

Rs = 1 - 6(sum of d^2 / n(n^2 - 1) )

64
Q

After working out correlation coefficient how do you then use the degree of freedom table

A

work out df
df= n1 + n2 -2

Compare your r value to each column

The 0.1 column states that you can 90% confident the data are correlated
The 0.05 column states you are 95% confident
0.025 = 97.5% confidence
0.01= 99% confidence

65
Q

what are adaptations

A

Characteristics that increase an organisms chance of survival and reproduction in its environment

66
Q

what are the three types of adaptations and give examples for each

A

Anatomical:
Body covering, Camouflage, Teeth, Mimicry

Behavioural (2 main categories = innate/instinctive and learned):
Survival – rabbits freeze when think they’ve been seen
Courtship – scorpion dance
Seasonal - Migration or Hibernation

Physiological:
Poison production, Antibiotic production, Water holding

67
Q

what is convergent evolution

A

when 2 species evolve similar characteristics independently of one another because they have adapted to live in similar environments.

68
Q

what are the adaptations of marram grass

A

curled leaves to minimise surface area
hairs on inside surface to trap moist air, reducing the diffusion
sunken stomata to limit transpiration
thick waxy cuticle reducing water loss through evaporation

69
Q

what are some examples of convergent evolution

A

marsupial and placental mice - both small and agile
flying phalangers and flying squirrels - gliders that eat insects and plants
marsupial and placental moles - borrow soft soil and streamlined

70
Q

what are selection pressures

A

factors that affect the organism chance of survival or reproduction

71
Q

what is the process of natural selection

A

1) organisms in a species show variation caused by differences in their genes. new alleles could come from a mutation
2) Organisms best adapted to the selection pressures have a better chance of surviving and successfully reproduce. “survival of the fittest”
3) These organisms pass the advantageous allele onto their offspring
4) the process repeats over generations so over time the proportion of individuals with the advantageous adaptation increases. the frequency of the allele increases in the gene pool
5) over long periods of time, a new species could evolve

72
Q

Give an example of a bacteria that has gained antibiotic resistance and why bacteria are able to gain resistance quicker than other organisms

A

MRSA
Bacteria reproduce very rapidly so evolve in a short time
As they reproduce more there is a higher chance a mutation can occur.

73
Q

how have peppered moth recently evolved

A

before the industrial revolution most peppered moths were pale as they were best camouflaged
over the revolution, trees became covered in soot so the pale moths stood out to predators. this meant the black ones survived and reproduced.
this meant the majority of the population of peppered moths were now black
since the clean air act of 1956, pollution has reduced, so trees are once again becoming lighter so the frequency of the pale allele in the moth gene pool has increased.

74
Q

how have sheep blowflies recently evolved

A

a pesticide was developed to kill the blowflies which are fatal to sheep
within 6 years they had developed a high level of resistance to the pesticides
this was because the flies had a pre-adaptation which meant some were already resistant
the ones with the gene survived and passed it onto their offspring

75
Q

how has flavobacterium recently evolved

A

live in waste water produced from factories
the bacteria have evolved to digest nylon which is beneficial to humans because they can clear factory waste
also it’s beneficial to the bacterium because they have another source of nutrients

ABHAYS A-LEVEL BIO FLASHCARDS (24 decks)

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