4.1 CLASSIFICATION AND EVOLUTION Flashcards
1
Q
What is classification?
A
Classification is the process by which living things are sorted into groups. The organisms within groups share similar features.
2
Q
What is phylogeny?
A
Phylogeny is the study of how closely related species are, looking at evolutionary relationships.
3
Q
What is taxonomy?
A
Taxonomy is the study of the principles behind classification. Uses similarities and differences to put them into groups.
4
Q
Why classify?
A
Why classify:
- to identify species
- to predict characteristics
- to find evolutionary links
5
Q
What is the Linnaean Classification System?
A
Linneaean Classification:
domain
kingdom
phylum
class
order
family
genus
species
6
Q
What are the 5 kingdoms?
A
The 5 kingdoms are fungi, protoctista, animalia, plantae, prokaryota
7
Q
What is a species?
A
Species are the smallest unit of classification and are a group of organisms that are able to produce fertile offspring.
8
Q
What is viable offspring?
A
Viable offspring means that the organism produced survives, but it is not capable of producing its own offspring.
Sometimes closely related species such as donkeys and horses can breed and produce offspring together. However, their offspring (a mule or hinny) is infertile. Therefore horses and donkeys are classified as a different species.
9
Q
Mules and Hinnies.
A
Mules and Hinnies:
- infertile as their cells contain an odd number of chromosomes (63)
- meiosis and gamete production cannot occur correctly as each chromosome must pair up
- they have 63 chromosomes because horses have 32 pairs while donkeys have 31 pairs
10
Q
What is the Binomial Nomenclature?
A
Binomial Nomenclature:
- all species have a name consisting of two parts
= first word = organisms genus (generic name)
= second word = organisms species (specific name)
- number of species have the same generic and specific name
11
Q
What is autotrophic?
A
Autotrophic is an organism that does not require organic nutrients.
12
Q
What is heterotrophic?
A
Heterotrophic is an organism that requires organic nutrients.
13
Q
What is saprotrophic?
A
Saprotrophic are organisms that release extra-cellular enzymes and absorb nutrients.
14
Q
What are the features of the prokaryota kingdom?
A
Prokaryota:
- unicellular = single cell or small groups of cells (prokaryotic)
- no membrane bound organelles
- no nucleus = ring/loop of DNA
- smaller ribosomes than eukaryotes
- peptidoglycan cell wall
- split into bacteria and amoeba
15
Q
What are the features of the protoctista kingdom?
A
Protoctista:
- all eukaryotic, all differ (defined by exclusion) = some have cellulose cell wall, some have chloroplasts
- protozoa, algae
16
Q
What are the features of the fungi kingdom?
A
Fungi:
- feed heterotrophically from dead things
- chitin cell wall
- unicellular or multicellular
- hyphae from mycellium
- most store food as glycogen
17
Q
What are the features of the plantae kingdom?
A
Plantae:
- multicellular, eukaryotic
- cellulose cell wall
- feed autotrophically = feed via photosynthesis, store food as starch
18
Q
What are features of the animalia kingdom?
A
Animalia:
- multicellular, eukaryotic
- feed heterotrophically = food stored as glycogen
- millions of species
- evolved, some disappear
- no cell wall
- membrane bound organelles
19
Q
How were things classified (early)?
A
Early classification:
- observable characteristics = morphology, anatomy
- similarities in behaviour = e.g living or moving in water/air
20
Q
What is morphology?
A
Morphology is the study of relationships of organisms’ structure.
21
Q
What is anatomy?
A
Anatomy is the study of the structures and organisms themselves.
22
Q
What advances in technology have happened to improve the way things are classified?
A
Advances in technology:
- light microscope
- electron microscope
- physiology
- biochemistry
23
Q
What is physiology?
A
Physiology is the way in which a living organism or body part functions.
24
Q
How are things classified (modern)?
A
Modern classification:
1. DNA
2. physiology
3. morphology
4. biochemistry
5. cytochrome C
= protein used in respiration (all organisms must have)
= amino acid sequence for the protein is different in all organisms
= the more similar it is, the more closely related the organisms
must be
25
What are Woese's findings?
Woese's findings:
- eukarya (80S ribosomes and RNA polymerase made up of 12 proteins)
- archea (80S ribosomes and RNA polymerase made up of 8-10 proteins)
- bacteria (70S ribosomes and RNA polymerase made up of 5 proteins)
- conducted these were 3 main domains
- as Woese divided prokaryotae into 2 domains (Eubacteria & Archea) this means that there would be 6 kingdoms = eubacteria, archaebacteria, protoctista, fungi, plantae, animalia).
26
What are the advantages of phylogenic classification?
Advantages of pylogenic classification:
- phylogeny can be done without reference to Linaean classification
- phylogeny influences classification
- phylogeny produces a continuous tree rather than discrete taxonomical groupings
- hierarchal style of classification can be misleading in evolutionary comparison, whereas phylogeny accounts for time
27
What is evolution?
Evolution is the theory that describes the way organisms change/evolve over many years as a result of natural selection.
28
What is natural selection?
Natural selection is the process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes.
29
What is the process of natural selection?
Process of natural selection:
1. mutation
2. variation within population
3. selection pressure
4. some survive, some die
5. reproduction to pass on allele/mutated gene
6. repeated over many generations
7. allele increases in population
30
What is uniformatarialism?
Uniformalarialism are natural processes that have shaped the land and have always done so (e.g sedimentation, wind erosion and deposition).
31
What were Darwin's observations?
Darwin's observations:
1. individuals within a species differ from each other- there is variation
2. offspring resemble their parents- characteristics are inherited
3. far more offspring are generally produced than survive to maturity- they suffer from predation, disease and competition
4. populations are usually fairly consistent in size
32
What were Darwin's conclusions?
Darwin's conclusions:
1. there is a struggle to survive
2. individuals better adapted to their environment have an advantage over others
3. they survive longer and reproduce more, passing on their successful characteristics to the next generation
33
What did Darwin and Wallace do as they had similar ideas?
As Darwin and Wallace has similar ideas, they proposed the theory of evolution through natural selection through a joint presentation of their 2 papers to the Linnaean society of London.
34
How is a fossil produced?
A fossil is produced when animal and plant remains are preserved in rocks.
35
What is the fossil record?
The fossil record suggest that organisms in different layers from oldest to youngest gradually change over time.
36
How old are the oldest cyanobacteria fossils?
The oldest cyanobacteria fossils are 3.5 billion years old.
37
What is the proof that life forms evolved over an extremely long period of time?
The proof that life forms evolved over an extremely long period of time is that simplest organisms are found in the oldest rocks and fossils of more complex organisms are found in the most recent rocks.
38
How can fossils prove there are ecological links between species?
Fossils can prove there are ecological links between species by the sequence in which organisms are found. E.g plant fossils found before animal fossils.
39
How can scientists use fossils to show how closely related organisms have evolved from the same ancestors?
Scientists can use fossils to show how closely related organisms have evolved from the same ancestors by studying the anatomy. E.g skull and skeleton.
40
What are strata?
Strata are a layer/series of layers of rock in the ground.
41
Why is the fossil record incomplete?
The fossil record is incomplete because many organisms are soft-bodied and decompose before they can fossilise. Conditions for fossils to from are not always present and some fossils have been removed by the Earth's movement.
42
Why has the function of pentadactyl limbs altered over time?
The function of pentadactyl limbs has altered over time as a result of evolution from a common ancestor.
43
What is comparative anatomy?
Comparative anatomy is the study of similarities and differences between an organisms anatomy.
44
What is a homologous structure?
A homologous structure is a structure that appears superficially different (and may perform different functions) in different organisms.
45
Why would you expect the limbs in vertebrates to be different?
You would expect the limbs in vertebrates to be different as they are used for a wide variety of functions such as running, jumping and flying.
46
What is thought to be the explanation behind the common bone structure in vertebrates?
The explanation behind the common bone structure in vertebrates is that all vertebrates have evolved from a common ancestor.
47
How are Darwin's finches and example of divergent evolution?
Darwin's finches are example of divergent evolution as in different environments, the finches beaks are shaped differently.
48
What is divergent evolution?
Divergent evolution shows how different species have evolved with a different set of adaptive features each.
49
When might divergent evolution occur?
Divergent evolution might occur when closely related species adapt to new habitats.
50
How homologous features provide evidence for divergent evolution?
Homologous features provide evidence for divergent evolution as although structures are similar, they can function differently.
51
What is comparative biochemistry?
Comparative biochemistry is the study of similarities and differences between the chemical make up of organisms.
52
What are the most important molecules that are highly conserved within most species and what do they do?
The most important molecules that are highly conserved within most species are cytochrome c, which is involved in respiration, and ribosomal RNA, which is involved in protein synthesis.
53
What is neutral evolution in terms of biochemistry?
Neutral evolution in terms of biochemistry suggests most of the viability in the structure of a molecule does not effect its function.
54
Where does the variability occur to allow it to be neutral?
To allow it to be neutral, the variability occurs outside of the molecules functional regions.
55
Why neutral evolution not affected by natural selection?
Neutral evolution is not affected by natural selections because it doesn't effect the function, so their accumulation is unaffected.
56
What can be said about evolutionary links between species and their sequence of amino acid in haemoglobin?
Species have similar proteins and may share a common ancestor they have evolved from.
57
What is the evidence that chimps are a humans closest living relative?
The evidence that chimps are a humans closest living relative as they have similar DNA and amino-acid bases.
58
Why is rRNA commonly used to determine relationships between species?
rRNA is commonly used to determine relationships between species as it has a very slow rate of substitution.
59
How do scientists discover how closely related two species are?
Scientists discover how closely related two species are by comparing the molecular sequence of the molecule and looking at the number of differences plotted against the rate the molecule undergoes substitution to estimate the point at which the two species last shared a common ancestor.
60
Species that are more closely related...
Species that are more closely related have more similar DNA and proteins.
61
What is variation?
Variation is the differences between individuals within or between species.
62
How does meiosis cause genetic variation?
Meiosis causes genetic variation by:
- different alleles
- crossing over
- independent assortment
- independent segregation
63
What are the other causes of genetic variation (no meiosis)?
Other causes of genetic variation:
- mutation
- random fusion of gametes
- chance
64
What is continuous variation?
Continuous variation is a characteristic that can take any value within a range.
- usually caused by genes and the environment
- polygenic
- e.g animal mass, leaf surface area
65
What is polygenic?
Polygenic is a trait whereby phenotype is influenced by more than one gene.
66
What is normal distribution?
Normal distribution is a function that represents the distribution of many random variables as a symmetrical bell-shaped graph.
67
What are the characteristics of a normal distribution curve?
Characteristics of a normal distribution curve:
- mean, mode and median are the same
- bell-shaped
- 50% of values less than mean, 50% greater than mean
- most values lie close to the mean value
68
What is discontinuous variation?
Discontinuous variation is a characteristic that can only appear in specific (discrete) values.
- mostly caused by genes
- usually caused by one (monogenic) or two genes
- examples include albinism, blood groups
69
What is interspecific variation?
Interspecific variation is variation that occurs between members of different species.
70
What is intraspecific variation?
Intraspecific variation is variation that occurs between members of the same species.
71
What are the causes of variation?
Causes of variation:
- organisms genetic material = e.g if genes have different alleles = eye colour
- environment in which organism lives = e.g presence of scars, tattoos
- genetic and environmental = e.g skin colour, height
72
What is standard deviation?
Standard deviation is the measure of how spread out the data is.
- the greater the standard deviation the greater the values
- therefore a more diverse population
- lower = less spread of values = less diverse
73
What is the equation for standard deviation?
Standard deviation= square root of the sum of the number of values minus the mean squared over the number of samples minus 1
74
What are error bars?
Error bars:
- if standard deviation has been calculated for data which has been graphed, SD can be represented as an error bar
- helps to assess the reliability of the data as it shows the spread of data at that point
- most reliable data = smallest error bar
- least reliable data = biggest error bar
75
What is a t-test?
A t-test is 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
- can be used to
= compare variation within a population
= compare the effects of biotic or abiotic factors
76
What do you need to calculate a t-test?
Calculate t-test:
- must be a big enough sample
- data should be normally distributed
- a null hypothesis is needed
77
What is a null hypothesis of a t-test?
A null hypothesis of a t-test states there is no significant difference between the mean of x and the mean of y.
78
What are the types of correlation?
Types of correlation:
- positive
- negative
- no correlation
79
What is Spearman's rank?
Spearman's rank (p) is a test used to discover the strength of a link (correlation) between two sets of data.
80
What do you need to calculate Spearman's rank?
Calculate Spearman's rank:
- must have 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
81
What is the null hypothesis of Spearman's rank?
The null hypothesis of Spearman's rank states that there is no statistically significant correlation between x and y.
82
What is adaptation?
Adaptation is a feature of a living organism that increases its chances of survival and reproductive success.
83
What does a well adapted organism need to survive?
In order to survive, a well adapted organism needs to:
- find enough nutrients/photosynthesize
- find enough water
- defend itself from predators/disease
- survive the physical conditions of the environment
- respond to changes
- still have enough energy to reproduce
84
What are the 3 different types of adaptation?
3 types of adaptation:
- anatomical - physical features, adapted internally/externally
- behavioural - responses to stimuli
- physiological - body processes
84
What are the 3 different types of adaptation?
3 types of adaptation:
- anatomical - physical features, adapted internally/externally
- behavioural - responses to stimuli
- physiological - body processes
85
What are the examples of anatomical adaptation?
Examples anatomical adaptation:
- body covering (protection, hair/scales/spikes/feathers/shells)
- camouflage (blend into habitat)
- teeth (easily eat food, molars/canines)
- mimicry (copying appearance and sound)
- plants (xerophytes)
86
What are the examples of behavioural adaptation?
Examples behavioural adaptation:
- survival (freezing, playing dead)
- courtship (attract a mate, dancing)
- seasonal migration (move from one region to another)
- seasonal hibernation (period of inactivity to reduce requirement for food)
- innate behaviour (inherited through genes, survive in habitat)
- learned behaviour (from experience of watching others)
87
What are examples of physiological adaptation?
Examples physiological adaptation:
- poison production (produce venom to kill)
- water holding (store water in body)
- antibiotic production (produce antibodies to kill bacteria)
88
What is convergent evolution?
Convergent evolution takes place when unrelated species begin to share similar traits, happens because organisms adapt to similar environments
89
What is a marsupial mole?
A marsupial mole is a type of mole that starts its life in the uterus then leaves and enters the marsupium when they are still an embryo.
White to orange colour range.
Found in Australia.
90
What is a placental mole?
A placental mole is a type of mole where the placenta connects the embryo to the mothers circulatory system in the womb where the embryo is nourished and allows it to reach a higher level of maturity before birth.
Grey in colour.
Found in America and Europe.
91
What adaptations to placental and marsupial moles share?
Marsupial and placental moles share a streamlined body shape, modified forelimbs for digging, velvety fur. These adaptations are used for digging, burrowing and moving through soil.
92
Why do species on different continents resemble each other?
Species on different continents resemble each other as they are both adapted to survive in different environments.
93
How long ago will species living in Australia and America shared a common ancestor?
Species living in Australia and America will have shared a common ancestor 100 million years ago.
94
What one feature accurately reflects the distinct evolutionary relationships between species in Australia and America?
One feature that accurately represents distinct evolutionary relationships is the way they reproduce.
95
What is another example of convergent evolution in animals?
Examples of convergent evolution in animals:
- marsupial and placental moles
- sugar gliders and flying squirrels
96
What is an example of convergent evolution in plants?
Example of convergent evolution in plants:
- aloe vera and agavae = both adapted to live in desert
97
What are the steps in natural selection?
Steps in natural selection:
1. genetic variation exists between individuals in a population
< selection pressures act on population (e.g disease, predators) >
2. individuals with alleles that allow them to cope best with selection pressures survive and breed
3. alleles encoding advantageous characteristics are more likely to be passed on to the next generation
4. over many generations, the frequency of advantageous alleles increases within the population. can eventually lead to evolution of a new species.
98
Why does evolution occur in a shorter time in populations of microorganisms than mammals?
Evolution occurs faster in microorganisms than mammals as they can reproduce via binary fission which is faster than sexual reproduction and when microorganisms split their offspring is 'cloned' and the alleles will be passed on, whereas in sexual reproduction the alleles are not always guaranteed to pass on to offspring.
99
Why does evolution happen in short bursts?
Evolution happens in short bursts as selection pressures are not always constant and do not always occur, and happen in periods of time that do not last forever.
100
What is happening in modern evolution?
Modern evolution:
- bacteria becoming resistant to antibiotics
- bedbugs/headlice/sheep blowflies becoming resistant to insecticides
- flavobacterium can digest nylon waste
- rat resistance to warfarin (rat poison)
- new virus strains emerging
- plant tolerance to toxic metals
- hedgehogs now run away instead of roll up
- rabbits resistance to myxomatosis
