1
Q
how many different organisms do scientists believe currently exist on earth?
A
8.7 billion
2
Q
what are classification systems?
A
the process by which living things are sorted into groups
3
Q
what does it mean when organisms are in the same group in the classification system?
A
they share similar characteristics
4
Q
what is phylogeny?
A
this is the study of how closely related species are, look at evolutionary relationships
5
Q
what is taxonomy?
A
the study of the principles behind classification (this uses differences and similarities and put them into groups)
6
Q
why do we classify things?
A
-to identify species
-to predict characteristics
-to find evolutionary links
7
Q
how is this single classification system utilised world wide?
A
by using a single classification system worldwide, scientists can identify links between different organisms even if they live on different continents
8
Q
what are the seven taxonomic groups in the Linnean classification system?
A
Kingdom
Phylum
Class
Order
Family
Genus
Species
9
Q
what happens as you move down the hierarchy of the taxonomic groups in the Linnean classification system?
A
as you move down the hierarchy there are more groups but fewer organisms in each group- the organisms in each group become more similar and share more of the same characteristics
10
Q
describe the species taxon
A
-smallest unit of classification
-same physiology, anatomy, morphology and behaviour
11
Q
define species
A
a species is a group of organisms that are able to reproduce fertile offspring
12
Q
what is binomial nomenclature?
A
all species are given a name consisting of two parts
13
Q
what is the first word of binomial nomenclature?
A
-the organisms genus
-must start with a capital letter
14
Q
what is the second word of binomial nomenclature?
A
-the organisms species
-must start with a small letter
15
Q
what form must the words in binomial nomenclature be in?
A
they should all be in italics and if handwritten then underlined
16
Q
which taxon includes the most specific characteristics?
A
species
17
Q
which taxon includes the broadest characteristics?
A
kingdom
18
Q
which taxon includes more species, an order or a family?
A
order
19
Q
which taxon includes only organisms that can successfully interbreed?
A
species
20
Q
if two organisms belong to the same family, what other taxonomic groups do the organisms have in common?
A
order, class, phylum, kingdom
21
Q
how many kingdoms are there?
A
5
22
Q
how many kingdoms did there used to be?
A
two (plants and animals)
23
Q
why did two kingdoms become five?
A
- as technology improved so did scientific knowledge
-this allowed plants to be separated into more kingdoms
24
Q
what are the different feeding systems?
A
-autotrophic
-heterotrophic
-saprotrophic
25
define autotrophic
an organism that transforms inorganic molecules into organic molecules (photosynthesis)
26
define heterotrophic
an organisms that has to eat and digest other organisms to gain organic molecules
27
define saprotrophic
organisms that release extra-cellular enzymes and absorb nutrients
28
what are some examples of fungi?
-mushrooms
-yeast
-mould
29
what are some examples of prokaryotes?
-bacteria
-blue green algae
30
what are some examples of protoctists?
-paramecium
31
what are the kingdoms?
-animals
-plants
-fungi
-prokaryotes
-protoctists
32
what are the characteristics of animals?
-are eukaryotes
-are multicellular
-have heterotrophic nutrition
-have fertilised eggs that develop into a ball of cells called a blastula
-are usually able to move around
33
what are the characteristics of plants?
-are eukaryotes
-are multicellular
-have cells surrounded by a cellulose cell wall
-produce multicellular embryos from fertilised eggs
-have autotrophic nutrition
34
what are the characteristics of fungi?
-reproduce by spores
-are eukaryotes
-have a mycelium which consists of hyphae (made up of long threads)
-have walls made of chitin
-have cytoplasm that is multinucleate
-are mostly free living and saprophytic, they cause the decay or organic matter
-never have cilia or flagella
35
what are the characteristics of prokaryotes?
-have no nucleus
-have a loop of naked DNA (DNA that is not associated with histone proteins) that is not arranged in linear chromosomes
-have no membrane bound organelles
-have smaller ribosomes than in other groups
-carry out respiration not in mitochondria, but on special membrane systems (mesosomes)
-have cells smaller than those of eukaryotes
-exist as single cells or small groups of cells
-cell wall contains peptidoglycon
-no visible feeding mechanisms, nutrients are absorbed through cell wall
36
what were prokaryotes called before?
Monera
37
what are the types of prokaryotes?
-archea
-bacteria
38
why was the kingdom protoctists made?
they can't be categorised into the other kingdoms
39
what are the characteristics of protoctists?
-are eukaryotes
-are mostly single celled
-show a wide variety of forms]-show various plant like and animal like features
-are mostly free living
-have autotrophic or heterotrophic nutrition, some photosynthesise, some ingest prey, some feed using extracellular enzymes and some are parasites
40
what are the ways monerans can get their food energy?
-saprotrophic
-parasitism
-mutualism
41
what was early classification like?
-based on observable characteristics (morphology and anatomy)
-similarities in behaviour (live or move in water/air)
42
what are some advances in technology that have helped improve classification systems?
-light microscope
-electron microscope
-physiology
-biochemistry
43
what is used now to classify organisms?
-DNA
-physiology and morphology
-biochemistry
44
how is DNA used in classification?
-the % similar DNA shows how close the evolutionary relationship is
-the higher the percentage the more closely related in evolution the organisms are and the lower the percentage the less closely related they are
45
how is biochemistry used in classification?
the more similar the protein amino acid sequence, the more closely related the organisms are in evolution and vice versa
46
what is the name of the common protein used in comparing amino acid sequences for classification?
cytochrome C
47
what is cytochrome C?
a protein used in respiration, therefore, in all living organisms
48
why is cytochrome C used in classification?
amino acid sequence is different in different organisms
49
how is cytochrome C used in classification?
-more similar = more closely related
-less similar = less closely related
50
what did Carl Woese suggest a new classification system based on?
-rRNA nucleotide sequences in eukaryotes and prokaryotes
-lipid structure and antibody sensitivity
51
what did Carl Woese suggest about prokaryotes due to his new classification system?
decided prokaryotes had 2 distinct groups based on molecular structure and metabolic pathway
52
what are the different domains?
-eukaryotes
-archaeae
-bacteria (eubacteria)
53
how many ribosomes do eukaryotes have?
80S ribosomes
54
how many ribosomes do archaeae have?
70S ribosomes
55
how many ribosomes do bacteria have?
70S ribosomes
56
how many proteins does eukaryotes RNA polymerase have?
has 12 proteins
57
how many proteins does archaeae RNA polymerase have?
has 8-10 proteins
58
how many proteins does bacteria RNA polymerase have?
has 5 proteins
59
what is phylogeny?
means the evolutionary history of a species
60
.
61
what happens as groups of organisms evolve from common ancestors?
they keep some of the same traits
62
what does a cladogram gram show?
shows how those traits diverge between species
63
what does it mean the closer 2 organisms are in a cladogram?
the more probable that they are closely related by evolution
64
draw an evolutionary tree to demonstrate the domains
*see paper flashcard*
65
describe continuous variation
a graduation in values from one extreme to another
66
describe continuous variation
a graduation in values from one extreme to another
67
what does continuous variation produce?
a bell curve = normal distribution
68
describe normal distribution curves
-same mean, mode and median
-bell shaped (symmetrical around mean)
-50% of values > mean
-50% of values < mean
- most values are close to the mean
69
what is standard deviation?
a measure of how spread out the data is around the mean
70
what does it mean the greater the standard deviation?
the greater the spread of values therefore a more diverse population
71
what does it mean the lower the standard deviation?
the less the spread of values and therefore less variation
72
what is the percentage of 1 standard deviation either side of the mean?
68% of the values
73
what is the percentage of 2 standard deviations of the mean?
95% of the values
74
75
define adaptations
a feature of living organisms that increases its chances of survival and reproductive success
76
in order to survive a well adapted organism must be able to what?
-find enough food/photosynthesise
-find enough water
-gather enough nutrients
-defend itself from predators/disease
-survive the physical conditions of the environment
-respond to changes
-still have enough energy to reproduce
77
what are the types of adaptation?
anatomical, behavioural and physiological
78
what is convergent evolution?
when organisms evolve similarities because they adapt to similar environments or other selection pressures- they are unrelated species but live in a similar way
79
what is an example of convergent evolution?
-marsupials in Australia and placental mammals in the rest of the world, strongly resemble one another because of the niches they fulfil
-these two subclasses separated in the Jurassic, over 100 million years ago
-despite this time and geographical distance, species from each sub class look and behave in exceptionally similar ways
80
what is anatomical adaptation?
these are physical features that have adapted both internally and externally
81
what are some examples of anatomical adaptation?
-body covering
-camouflage
-teeth
-mimicry
-plants= xerophytes
82
describe body covering
these are things such as hair, scales, spines and feathers- these can help organisms to fly, help it to stay warm etc.
83
what is a specific example of animal with a body covering adaptation?
snail shells provide protection
84
describe camouflage
the outer colour of an animal allows it to blend into its environment, making it harder for predators to spot it
85
what is a specific example of an animal with a camouflage adaptation?
snowshoe hare is white in winter to match the snow and brown in summer to match the soil
86
describe the adaptation of teeth
the shape and type of teeth present in an animals jaw are related to its diet
87
what is a specific example of an animal with a teeth adaptation?
herbivores such as sheep have continuously growing molars for chewing soft grass
88
describe mimicry
copy another animals appearance or sounds allows a harmless organism to fool predators into thinking it is poisonous
89
what is a specific example of an animal with a mimicry adaptation?
the harmless hoverfly mimics the marking of a wasp
90
describe plants with anatomical adaptations
xerophytes have:
-curled leaves to minimise surface area
-hairs on inside of leaves to trap moist air
-stomata sunk into pits
-thick waxy cuticle
91
what is behavioural adaptation?
these are responses to stimuli that increase the chances of survival
92
what are some examples of behavioural adaptations?
-survival
-courtship
-seasonal migration
-season hibernation
-innate behaviour
-learned behaviour
93
what is a specific example of an animal with a survival adaptation?
an opossum plays dead when threatened
94
describe courtship
many animals exhibit elaborate courtship behaviours to attract a mate
95
what is a specific example of an animal with a courtship adaptation?
scorpions perform a dance to attract a partner
96
describe seasonal migration
animals move from one region to another and then back again when environmental conditions are more favourable
97
what is a specific example of an animal that migrates seasonall?
humpback whale
98
describe seasonal hibernation
a period of inactivity in which an animals body temperature, heart rate and breathing rate slow down to conserve energy reducing the animals requirement for food
99
what is a specific example of an animal that hibernates?
hedgehog
100
describe innate behaviour
the ability to do this is inherited through genes which allows the organisms to survive in the habitat in which it lives
101
what is a specific example of an animal with an innate behaviour adaptation?
the behaviour of spiders to build webs
102
describe learned behaviour
these adaptations are learnt from experience or from observing other animasl
103
what is a specific example of an animal with a learned behaviour adaptation?
sea otters use stones to hammer shells off rocks
104
what are physiological adaptations?
body processes that help an organism to survive
105
what are some examples of physiological adaptations?
-poison production
-water holding
106
describe poison production
many reptiles produce venom to kill their prey and many plants produce poisons in their leaves
107
what is a specific example of an animal with a poison production adaptation?
king cobra
108
describe the adaptation water holding
storing water in its body which allows it to survive without water for a long period of time
109
what is a specific example of an animal with a water holding adaptation?
cacti
110
what is a marsupial mole?
a mole where life starts in the uterus, but then leave and enter the marsupium (pouch) while they are still embryos- they complete their development here by suckling milk
111
what is a placental mole?
a mole that reproduces by a placenta that connects the embryo to its mothers circulatory system in the uterus- this nourishes the embryo allowing it to reach a high level of maturity before birth
112
what are the adaptations that marsupial moles and placental moles share?
-both burrow through soft soil to find worms
-streamlined body shape and modified forelimbs for digging
-velvety fur which allows smooth movement through soil
113
marsupials are found in Australia and placental mammals in America, why do species on different continents resemble each other?
they have adapted to similar climates and food supplies
114
there are several species that have evolve separately in Australia and America, how long ago would they have shared a common ancestor?
more then 100 million years ago
115
what are the general areas in which these species that demonstrate convergent evolution show a resemblance?
overall shape, type of locomotion and feeding techniques
116
what is the one feature that accurately reflects the species who demonstrate convergent evolutions distinctive evolutionary relationships?
methods of reproduction
117
what is a t-test?
-a statistical test that can be used to compare the means of 2 populations
-to see if there is a significant difference between the two values
118
what can a t-test be used to?
-compare variation within a population
-compare the affects of biotic and abiotic factors
119
how do you calculate a t-test?
-there must be enough data collected
-data should be normally distributed
-a null hypothesis is needed
120
what is a null hypothesis in a t-test?
there is no significant difference between the mean of... and the mean of...
121
what do you do once you have found a value for t in a t-test?
-to know what that number means you have to compare it to a critical value using a table
-to do this you must find the degrees of freedom
122
how do you find the degrees of freedom in a t-test?
(N1 + N2) - 2
123
what column do we always use in statistical tests?
0.05 probability
124
what are the rules for every stats test in biology?
-above critical value= reject null hypothesis as there's a significant difference
-below critical value= accept null hypothesis as any difference is just due to chance and is not significant
125
what is the sentence you use for every conclusion when doing a t-test?
As the t value of ___ is higher/lower that the critical value of ___ at the 0.05 probability, then we can reject/accept the null hypothesis. As there is/is not a significant difference between the means of population 1 and 2.
126
describe spearman's rank
-need 2 sets of data
-can be used if the variables do not have a linear relationship
-data does not have to be in a normal distribution
127
in spearman's rank what number demonstrates a perfect positive correlation?
+1
128
in spearman's rank what number demonstrates a perfect negative correlation?
-1
129
in spearman's rank what number demonstrates no correlation?
0
130
what is the null hypothesis used in spearman's rank?
there is no statistically significant correlation between... and...
131
when ranking values in spearman's rank what value do you always start with?
1 which is the lowest values
132
what do you do once you have found the spearman's rank value?
-to know what that number means you have to compare it to a critical value using a table
-the degrees of freedom is the number of pairs you are using (n)
133
what is the sentence you use for every conclusion when doing a spearman's rank?
As the spearman's rank value of ___ is higher/lower than the critical value of ___ at the 0.05 probability, then we can reject/accept the null hypothesis. As there is/is not a statistically significant correlation.
134
when calculating spearman's rank how do you calculate the rank of variables that are the same?
add the ranks that they should be together e.g. (1+2+3+4) and then divide it by the number of values (4) so each value would be ranked 2.5 and then the next rank would continue as 5
135
what are some examples of modern evolution?
-bacteria becoming resistant to antibiotics
-rat resistance to warfarin
-plant tolerance to toxic metals
-hedgehogs that run away instead of roll up
136
explain why evolution occurs in a shorter time in populations of microorganisms, than in populations of mammals
-microorganisms have a shorter life cycle and in every generation, mutations can occur
-mammals have a longer life cycle, so mutations occur less frequently
-even selection pressures still require a few generations to cause change
137
explain why evolution tends to happen in short bursts
-when the environment changes, this places a new selection pressure on the species
-if there are advantageous variations, these are selected for and the species changes
-once the population is well adapted to the new environment, the changes will slow down or stop
138
how could you tell if the species living in one area developed into a new species living in a different area?
Interbreed the two species, one from each area; if they breed and produce offspring which when grown can also produce offspring then they are still one species; if they do not breed or breed to produce offspring which are sterile then they have evolved into different species
139
define evolution
theory that describes the way that organisms change over many years due to natural selection
140
define natural selection
the process by which organisms best suited to their environment survive and reproduce, passing on their alleles to their offspring
141
outline the relevance of Darwin
-in 1809 creationism was an overriding belief
-Darwin was a naturalist
-he rode in a ship named Beagle in 1931 for a round the world trip
-in Galapagos he studied finches
-he started to see that those best suited survived and passed on characteristics
-experimented on pigeon variation
142
what theory did Darwin propose?
proposed theory of natural selection
143
what theory did Lyell propose?
suggested fossils were evidence of animals from millions of years ago and the principle of uniformitarianism (earth was shaped by forces like erosion)
144
what theory did Wallace propose?
sent his theories of natural selection to Darwin for peer review- they were the same!
145
what happened when both Wallace and Darwin came up with the same theory?
their theory of evolution was proposed in a joint presentation to the Linnaean society
146
what was the name of the book that Darwin released?
The origin of species
147
why was 'The origin of species' controversial?
-went against creationism
-suggested man descended from apes
148
what are the stages of the process of natural selection?
1. mutation
2. variation
3. selection pressure
4. reproduction to pass on allele
5. repeated over many generations
6. allele increases in population
149
describe the mutation stage of natural selection
provides alleles (variation)
150
describe the variation in population stage in natural selection
variation within a species increases the species chance of survival if conditions change
151
what is a selection pressure?
factors that affect an organisms chance for survival
152
what are some examples of a selection pressure?
when one of these changes, this is a selection pressure:
-find food
-avoid predation
-survive harsh environments
-defend a territory
-find a mate
-raise young
153
describe the reproduction to pass an allele stage of natural selection
-all living things reproduce at a rate that is unsustainable to ensure that some survive to pass on genes
-those who have the advantageous characteristics are most likely to survive and reproduce and pass on the advantageous characteristic
154
what are some objections to the theory of natural selection?
-gaps in the fossil record
-surely natural selection would eliminate all exaggerated characteristics, but this can be explained by "sexual selection"
-went against creationism
-didn't think the world was old enough
155
what are the evidence for evolution?
-palaeontology
-anatomy
-biochemistry
156
how is palaeontology evidence for evolution?
-shows evolutionary links
-found in different aged rocks
-shows similarities and differences in anatomy
157
how is anatomy evidence for evolution?
comparative, so the more similar the more closely related
158
how is biochemistry evidence for evolution?
-looks at DNA, protein structure and others
-the more similar the structure, the more closely related they are
159
how is a fossil produced?
when animal and plant remains are preserved in rocks
160
what is the fossil record?
a sequence of fossils from oldest to youngest, which shows that organisms have gradually changed overtime
161
what is the proof that life forms evolved over an extremely long period of time?
fossils of the simplest organisms are found in the oldest rocks, whilst fossils of more complex organisms are found in more recent rocks
162
how old are the oldest cyanobacteria fossils?
3.5 billion years old
163
how can fossils prove there are ecological links between species?
the sequence in which the organisms are found matches their ecological links to each other
164
how can scientists use fossils to show how closely related organisms have evolved from the same ancestors?
by studying the similarities in the anatomy of fossil organisms
165
are the oldest fossils in the lowest or highest rock layers?
lowest
166
what are strata?
layers of rock
167
why is the fossil record incomplete?
-many organisms are soft bodied and decompose quickly before they can fossilise
-the conditions needed for fossils to form are not always present
-many fossils have been destroyed
168
why has the function of these pentadactyl limbs altered over time?
as a result of evolution from a common ancestor
169
what is comparative anatomy?
the study of similarities and differences in the anatomy of different living species
170
what is a homologous structure?
a structure that appears superficially different in different organisms, but has the same underlying structure
171
why would you expect the limbs in vertebrates to be different?
the limbs are used for a wide variety of functions so the bone structure is different for different functions
172
what is thought to be the explanation behind the common bone structure in vertebrates?
all vertebrates have evolved from a common ancestor, therefore vertebrate limbs have all evolved from the same structure
173
what is divergent evolution?
this describes how, from a common ancestor, different species have evolved, each with a different set of adaptive features
174
when might divergent evolution occur?
when a closely related species diversify to adapt to new habitats as a result of migration or loss of habitat
175
how do homologous features provide evidence for divergent evolution?
shows superficial structures that are different
176
what is comparative biochemistry
the study of similarities and differences in the proteins and other molecules that control life processes
177
what are the important molecules that are highly conserved within most species and what do they do?
-cytochrome C (protein involved in respiration)
-ribosomal RNA
178
what is neutral evolution in terms of biochemistry?
states that most of the variability in the structure of a molecule does not affect its function
179
where does the variability occur to allow it to be neutral?
outside of the molecules functional regions
180
why is neutral evolution not affected by natural selection?
due to the fact that they have no effect on function, their accumulation is not affected by natural selection
181
what is the evidence that chimps are a humans closest living relative?
they have very similar DNA sequences, they have been found to share at least 985 of their DNA
182
why is ribosomal RNA commonly used to determine relationships between species?
it has a very slow rate of substitution
183
how do scientists discover how closely related two species are?
the molecular sequence of a particular molecule is compared by look at:
-the order of DNA bases
-the order of amino acids in protein
184
what do scientists then estimate after the molecular sequence has been compared?
the point at which two species last shared a common ancestor
185
species that are more closely related...
have more similar DNA and proteins
186
what is variation?
the differences between individuals within or between a species
187
describe discontinuous variation
-individuals fall into a number of distinct categories
-based on features that cannot be measured across a range
-there are no inbetween values
-environment has no effect
188
how many genes is discontinuous variation controlled by?
one
189
how is discontinuous variation represented?
bar chart
190
describe continuous variation
-complete range of measurements from one extreme to another
-get a normal distribution curve due to the graduation from one extreme to another
-significantly affected by environment
191
how many genes is continuous variation controlled by?
many genes
192
how is continuous variation represented?
histogram
193
what is interspecific variation?
variation between members of different species
194
what is intraspecific variation?
variation between members of the same species
195
what are the causes of variation?
-genes
-environment
196
give some examples of genetic variation
-eye colour
-blood group
-ear lobes
197
give some examples of both genetic and environemental variation
-height
-weight
-hair colour
198
give some examples of environmental variation
-language (accent)
-scars
199
what are the different genetic causes of variation?
-alleles
-mutations
-crossing over
-independent assortment
-sexual reproduction
-chances
200
how does alleles cause genetic variation?
individuals in the same population may inherit different versions of the same gene
201
how does mutations cause genetic variation?
Changes to the DNA nucleotide sequence can cause changes to the tertiary structure of a protein. If this occurs in a somatic cell then just the individual is affected, if it occurs in the gametes it can be passed on to offspring. Both cause variation.
202
how does crossing over cause variation?
Non sister chromatids will form chiasmata during prophase 1 of meiosis. This allows for the shuffling of alleles between the chromatids and increases variation.
203
how does independent assortment cause variation?
Homologous chromosomes line up randomly in the equator of the cell during metaphase 1. This is then repeated when chromatids line up randomly in the equator in metaphase 2.
204
how does sexual reproduction cause variation?
This can often be called random fertilisation as there are so many genetically different gametes produced by meiosis. Individuals will contain a unique genetic code.
205
how does chance cause variation?
individuals produced different from their parents. This is because they inherit different genes from each of the parents.
206
why are twins used in variation studies?
they have the same genetic makeup so any differences in characteristics can be said to be caused by the environment
207
why do differences in twins increase as they age?
they have an increased amount of different environmental influences
A level OCR Biology Module 4
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