Module 4- Biodiversity, evolution and disease Flashcards
(95 cards)
1
Q
What is classification?
A
The name given to the process by which living organisms are sorted into groups.
2
Q
What are the groups used for classification referred to as?
A
Taxonomic groups
3
Q
What are the seven groups of classification?
A
Kingdom, phylum, class, order, family, genus and species.
4
Q
What is the mnemonic used to remember the taxonomic groups?
A
King Phillip came over for great sex.
5
Q
Which is the biggest and broadest taxonomic group?
A
Kingdoms
6
Q
What is the smallest and most specific classification?
A
Species
7
Q
Why do scientists classify organisms? (3 reasons)
A
- To identify species as using a clear defined system helps that.
- To predict characteristics- if several members in a group have a specific characteristic, it is likely that another species in the same group will have the same characteristic.
- To find evolutionary links- species in the same group probably share characteristics because they have evolved from a common ancestor.
8
Q
How does the classification system begin?
A
The classification system begins with the three domains.
9
Q
What are the three domains?
A
Archaea, bacteria, and eukarya.
10
Q
Define species
A
A group of organisms that are able to reproduce to produce fertile offspring.
11
Q
What is the binomial naming system?
A
The naming system used to identify the same organism.
The first word of the name is the genus, e.g Homo and the second word of the name is the species, e.g Sapiens, therefore the name of the organism is homo sapiens and can be recognised worldwide and easily compared to other organisms.
12
Q
Give an example of the binomial naming system being used…
A
E.coli
Scientific name: Escherichia coli
Genus: Escherichia
Species: coli
13
Q
State two reasons why classification important
A
- Enables scientists to share information / makes communication easy.
- Provides information about an organism, based on members of the same group.
- Allows accurate identification of an organism.
14
Q
What are the five kingdoms?
A
Prokaryotae(bacteria) Protocista(the unicellular eukaryotes) Fungi(e.g mould) Plantae(the plants) Animalia(the animals)
15
Q
Why were the five kingdoms initially categorised into ppfpa?
A
Because of their similarities in their observable features.
16
Q
Give the general features of prokaryotae
A
- Unicellular
- No nucleus or other membrane-bound organelle- a ring of naked DNA- small ribosomes.
- No visible feeding mechanism- nutrients are absorbed through the cell wall or produced internally by photosynthesis.
17
Q
Give the general features of protocista
A
- (mainly) unicellular
- A nucleus and other membrane-bound organelles.
- Some have chloroplasts.
- Some are immobile but some move by flagella.
- Nutrients are acquired through photosynthesis(autotrophic feeder) and ingestion of other organisms(heterotrophic feeders).
18
Q
Give the general features of fungi
A
- Unicelular or multicellular
- A nucleus and other membrane-bound organelles and a cell wall mainly composed of chitin.
- No chloroplasts or chlorophyll
- No mechanisms for locomotion
- Most have a body made of hyphae or threads.
- Nutrients are acquired by absorption- mainly from decaying material- they are saprophytic feeders- some are parasitic.
- Most store their food as glycogen.
19
Q
Give the general features of plantae
A
- Multicellular
- A nucleus and other membrane-bound organelles including chloroplasts, and a cell wall mainly composed of cellulose.
- All contain chlorophyll
- Most do not move
- Nutrients are acquired by photosynthesis- they are autotrophic feeders(organisms that make their own food).
- Store food as starch.
20
Q
Give the general features for animalia
A
- Multicellular
- A nucleus ansd other membrane bound organelles (no cell walls).
- No chloroplasts
- Move with the aid of cilia, flagella or contractile proteins, someties in the form of muscular organs.
- Nutrients are acquired by ingestion- they are heterophobic feeders.
- Food stored as glycogen.
20
Q
Give the general features for Animalia
A
- Multicellular
- A nucleus ansd other membrane bound organelles (no cell walls).
- No chloroplasts
- Move with the aid of cilia, flagella or contractile proteins, someties in the form of muscular organs.
- Nutrients are acquired by ingestion- they are heterophobic feeders.
- Food stored as glycogen.
21
Q
Why do scientists compare the DNA and proteins of different species?
A
Scientists compare similarities of DNA and proteins of different species to siscover the evolutionary relationships between the species- when an organism evolves their DNA changes which determines the proteins that are made which determines the characteristics.
22
Q
Who proposed the “Three Domain System”? and when?
A
Carl Woese in 1977.
23
Q
How did Woese group his organisms?
A
Woese system groups organisms using differences in the sequences of nucleuotides in the cells’ ribosomal RNA(rRNA), as well as the cells’ membrane lipid structure and their sensitivity to antibiotics. Observation of these was made possible by scientific advancement.
24
What are the three domains proposed by Carl Woese? And what are their features?
Eukarya: 80s ribosomes, RNA polymerase contains 12 proteins.
Archaea: 70s ribosomes, RNA polymerase contains between 8 and 10 proteins and is very similar to eukaryotic ribosome.
Bacteria: 70s ribosomes, RNA polymerase contain 5 proteins.
25
What are the six kingdoms proposed by Carl Woese?
Archaebacteria, Eubacteria, Proticista, Fungi, Plantae and Animalia.
26
Why are Archaebacteria and Eubacteria not in the same kingdom despite them both being single-celled prokaryotes?
The are classified inot their own kingdom because their chemical makeup is different from eachother. For example, Eubacteria contain peptidoglycan in their cell wall whereas Archaebacteria do not.
27
What type of environments do archaebacteria live in?
Extreme environments, e.g hot thermal vents, anaerobic conditions and highly acidic environments- sewage treatment plants.
28
Define phylogeny
The evolutionary relationships between organisms. The study of evolutionary history of group of organisms is known as phylogenetics. It reveals which group a particular organism is related to, and how closley related these organisms are.
29
What are the advantages of phylogeny trees?
Phylogeny produces a continious tree whereas classfification requires discrete taxonomicall groups. Scientists are not forced to put organisms into a specific group that they do not quite fit.
The Linnean classification system can be misleading as it implies different groups within the same rank are equivalent.
30
Why was the book " On the origin of species" very controversial when released in 1859?
The theory evolution by natural selection confilcted with the religious view that God had created all of the animals and plants on Earth in their current form, and only about six thousand years ago.
31
What are the three main sources of evidence for evolution?... and describe them?
Palaeontology- The study of fossils and fossil record.
Comparative anatomy- Studying the similarities and differences between organisms anatomy.
Comparitive biochemsitry- Studying the similarities and differences between the chemical makeup of organisms.
32
When does divergent evolution occur?
When closely related species diversify to adapt to new habitats(which means that they have adaptive features) as a result of migration or loss of habitat.
33
What is a homologous structure?
A structure that appears superficially different(and may perform different functions) in different organisms but has the same underlying structure, e.g pentadactyl limb of vertebrates.
34
What did Charles Darwin do for the development of the theory of evolution?
Darwin came up with the theory of evolution by natural selection through observations in the galapagos islands.
35
How are fossils formed?
Fossils are formed when animal and plant remains are preserved in rocks. Over long periods of time, sediment is deposited on the Earth to from layers(strata) of rock. Different layers correspond to different geological eras, the most recent layer being found on the top. within different rock strata, the fossils found are quite different, forming a sequence from oldest to youngest, which shows that organisms have gradually changed over time. This is known as the fossil record.
36
How does the fossil record provide evidence for evolution?
Fossils of the simplest organisms such as bacteria and simple algae are found in the oldest rocks, whilst fossils of more complex organisms such as vertebrates are found in more recent rocks. This supports the evolutionary theory that simple life forms gradually evolved over an extremely long time period into more complex ones.
By studying similarities in the anatomy of fossil organisms, scientists can show how closely related organisms have evolved from the same ancestor. For example zebras and horses, members of the genus Equus, are closely relayed to the rhinoceros of the family Rhinocerotidae. An extensive fossil record of these organisms exists, which spans over 60 million years and links them to the common ancestor Hyracotherium. This lineage has been based on structural similarities between their skull(including teeth and skeleton, in particular the feet.
Fossils allow relationships between extinct and living(extant) organisms to be investigated.
37
How do fossils provide evidence that humans require plants to survive?
The sequence in which the organisms are found matches their ecological links to each other. For example, plant fossils appear before animal fossils. This is consistent with the fact that animals require plants to survive.
38
What are the limitations of the fossil record in providing evidence for evolution?
The fossil record is, however, not complete. For example, many organisms are soft-bodied and decompose quickly before they have a chance to fossilise. The conditions neded for fossils to form are not often present. Many other fossils have been destroyed by the Earth's movement, such as volcanoes, or still lie undiscovered.
39
What provides evidence for divergent evolution?
The presence of homologous structures.
40
How does the comparison of biochemistry with the species similarities and differences provide evidence for evolution?
Slight changes that occur in the molecules of the species can help identify evolutionary links. To study how closely two species are related, the molecular sequence of a particular molecule is compared( Scientists do this by looking at the order of thr DNA bases, or at the order of amino acids in a protein.) The number of differences that exist are plotted against the rate the molecule undergoes neutral base pair substitutions(which has been determined through studies). From this information scientists can estimate the point at which the two species last shared a common ancestor. Species that are closely related have the more similar DNA and proteins, whereas those that are distantly related have far fewer similarities. Ribosomal RNA has a very slow rate of substitution, so it is commonly used together with fossil information to determine relationships between ancient species.
41
What is the wildest type of variation between?... and what is this known as?
The wildest type of variation is between members of different species- these differences are known as interspecific variation. For example, a mouse has four legs, teeth, and fur whereas a bird has two legs, two wings, a beak and feathers.
42
What are differences between organisms within a species called? Give an example.
Intraspecific variation.
For example, people vary in height, build, hair colour, and intelligence.
43
What are the two factors that cause variation?
An organisms genetic material- differences in the genetic material an organism inherits from its parents leads to genetic variation.
The environment in which the organism lives- this casuses environmental variation.
44
What is genetic variation because of?
Genetic variation is due to the genes(and alleles) an individual possesses.
45
What are the 5 main reasons for gentic variation?
1. Alleles
2. Mutations
3. Meiosis
4. Sexual reproduction
5. Chance
46
How does variaton in alleles cause genetic variation?
Genes have different alleles. With a gene for a particular characteristic, different alleles produce different effects. For example, the gene for human blood groups can be produced(A,B,AB and O). Individuals in a species population may inherit different alleles of a gene.
47
How do mutations cause genetic variation?
Changes to the DNA sequence and therefore to genes can lead to change in the proteins that are coded for. These protein changes can affect physical and metabolic charateristics. If a mutation occurs in somatic(body) cells, just the individual is affected. However, if a mutation occurs in the gametes it may be passed on to the organisms offspring. Both can result in variation.
48
How does meisosis cause variation?
Gametes(sex cells-ovum and sperm) are produced by the process of meiosis in organisms that reproduce sexually. Each gemetes receives half of the genetic content of a parent cell. Before the nucleus divides and chromatids of a chromosome separate, the genetic material inherited from the two parents is 'mixed up' by independent assortment and crossing over. This leads to the gametes of an individual showing variation.
49
How does sexual reproduction lead to genetic variation?
The offspring produced from two individuals inherits geens(alleles) from each of the parents. Each individual produced therefore differs from the parents.
50
How does chance lead to genetic variation?
Many different gametes are produced from the parental genome. During sexual reproduction it is a result of chance as to which two combine(often referred to as random fertilisation).
The individuals produced therefore also differ from their siblings as each contains a unique combination of genetic material.
51
Is there greater variation in organisms that reproduce sexually or asexually?
There is greater genetic variation from organisms that reproduce sexually as asexual reproduction can only be increased in the organisms as a result of mutation. Also in asexual reproduction the result is clones that have identical genetic variation to their parents so they rely on mutation for genetic variation.
52
Give an example of a charaterisitics that is purely determined by genetic variation?
Your blood group.
| The genes passed onto you from your parents determine if your blood group will be type A, B, AB or O.
53
Why are plants more affected than animals by their environment?
This is due to the lack of mobility for the plants in the enviornment in comaprison to the animals that are free to move in their environment(but can vary depending on species, e.g snail=very slow cheetah=very fast).
54
Give an example as to how a plant is affected by a lack of mobility.
Two rose bushes are planted in different positions in a garden. The one that has greater access to the sun will generally grow larger than one in a shadier position. As the plant cannot move to gain sunlight, it is more affected by the environment than an animal, which could move to another area to look for food or shelter.
55
Give an example of a characteristic that is determined purely by environmental variation?
The presence of absence of any scars on your body. They will have occured as a result of an accident or disease and have no genetic origin. Scars cannot be inherited from a parent.
56
Why can it be difficult to investigate and draw conclusions about the causes of variation in any particular case?
It can be difficult to investigate the sole reason for variation because many characteristics are caused by a combination of both genetic and environmental causes. This is known as the 'nature vs nurture' argument.
57
Why is variation represented graphically?
This allows any patterns within the variation data to be seen clearly.
58
Based on the data shown from variation, characteristics can be sorted into what categories?
Discontinuous variation and continuous variation.
59
What is discontuous variation?... give an example.
Discontinuous variation is determined purely by genetic factors. An animal's sex is an example of discontinious variation as there are only two possible functional values- male or female. An example of discontinuous variation in microorganiams is the shape of bacteria. They can be spherial(cocci), rods(bacilli), spiral(spirilla), comma(vibrios) or corkscrew shaped(spirochaetes).
60
What are the main methods of displaying data on discontinuous variation?
It is almsot always displayed using a bar chart but sometimes a pie chart is used.
61
What is continuous variation?... give an example.
A characteristic that is controlled by a number of genes(polygenes). They are also often influenced by environmental factors.
A characteristic that can take any vlaue within a range issaid to show continuous variation. There is a graduation in vlaues from one extreme to the other of a characteristic- this is known as continuum. The height and mass of plants and animals are examples of such characteristics.
62
What are the main methods of displaying data on continuous variation?
Data on characterisitcs that show continuus variation are collecteed in a frequency table. These data are then plotted onto a histogram. Normally a curve is then drawn onto the graph to show the trend.
63
What are the four characteristics of normal distribution for continuous and discontinuous variation?
1. The mean, mode and median are the same.
2. The distribution has a characteristic 'bell shape', which is symmetrical about the mean.
3. 50% of values arre less than the mean and 50% are greater than the mean.
4. Most values lie close to the mean value- the number of individuals at the extremes are low.
64
What is standard deviation?
Standard deviation is a measure of how spread out the data is. The greater the standard deviation is, the greater the spread of the data. In terms of variation, a characteristic which has a high standard deviation has a large amount of variation.
65
What is the formula for standard deviation?
σ= √∑x-x̄)^2 / n-1
Standard deviation= Square root of the sum of the (value measured-mean value) squared divided by the total number of values in the sample-1.
```
Σ= the sum(total) of
x= value measured
x̄= mean value
n= total number of values in the sample
```
66
What are the main steps involved in calculating standard deviation?
1. Calculate the mean value(x̄)
2. Subtract the mean value from each measured value(x-x̄)
3. Square each of these values (x-x̄)^2
4. Sum each of these values ∑(x-x̄)^2
5. Divide this value by the sample size minus one ∑(x-x̄)^2 / n-1
6. Find the square root of this value √∑(x-x̄)^2 / n-1.
67
What is the student's t-test used for?
The students t- test is used to compare the mean values of two sets of data. To use this test the data collected must be normally distributed and enough data shoul be collected to calculate a reliable mean.
Different sample sizes may be used.
68
What is the students t-test formula?
t=(x̄1-x̄2) / √(σ1^2 /n1) +(σ2^2 / n2)
x̄1, x̄2= mean of populations 1 and 2.
σ1,σ2= standard deviation of populations 1 and 2.
n1,n2= total number of values in samples 1 and 2.
69
What is the method to use the students t-test?
1. State the null hypothesis
2. Subtract the mean petiole length of sample 2 from sample one (x̄1-x̄2).
3. For both populations, square the standard deviation and divide by the number in the sample (Population 1:σ1^2 / n1) (Population 2:σ2^2 / n2)
4. Sum these values of the populations.
5. Square root this value
6. Calculate students t-test
70
How do you understand what the students t test signifies?
Using a significance table.
First calculate a quantity known as the 'degrees of freedom' (df) using the formula: df=(n1+n2)-2 where n1= population 1 and n2= population 2. Then look at the corresponding probability values. For the data to be considered significantly different from chance alone, the probability(p) must be 5%(0.05) or less.
AT df=??, the value of ??? falls between ?% and?%.
The null hypothesis should be accepted, as we cannot be more than 95% percent confident that the results are not down to chance. We therefore cannot conclude that there is a significant difference between the ??? and ??? in the ??? and the ???.
71
What is the spearman's rank correlation?
The spearman's rank correlation means that two sets of data are related they are said to be correlated.
72
What are the three correlations that a spearman's rank correlation coefficient test can show?
No correlation- no relationship between the data.
A positive correlation(y=x)- As one set of data increases in value, the other set of data also increases in value.
A negative correlation(y=-x)- As one set of data increases in value, the other set of data decreases in value.
73
What is the formula for spearman's rank?
```
rs=1- 6∑d^2 / n(n^2-1)
rs= correlation coefficent
d= difference in ranks
∑= the sum (total) of
n= number of pairs of data.
```
74
In data sets of the spearman's ranks, what does a value of +1 show?
A perfect positive correlation
75
In data sets of the spearman's ranks, what does a value of -1 show?
A perfect negative correlation.
76
In data sets of the spearman's ranks, what does the value of 0 show?
No correlation
77
What are adaptations?
Adaptations are charateristics that increase an organisms chance of survival and reproduction in its environment. Adaptations can be divided into three groups.
78
What are the three groups of adaptations?
Anatomical adaptations- physical features (internal and external)
Behavioural adaptations- the way an organism acts. These can be inherited or learnt from their parents.
Physiological adaptations- processes that take place inside an organism.
79
Give some example of anatomical adaptations.
Body covering- animals have a number of different body coverings such as hair, scales, spines, feathers, and shells. These can: help the organism to fly, such as feathers on birds- help it to stay warm, such as the thick hair omn polar bears- provide protection, such as snail's shell. Thick waxy layers on plants prevent water loss and spikes can deter herbivores and protect the tissues from sun damage.
Camouflage- the outeer clour of an animal allows it to blend ito its environmnet, making it harder for predators to spot it. For example, the snowshoe hare is white in winter to match the snow, and turns brown in summer to blend in with the soil and rock environment in which it lives in.
Teeth- the shape and type of teeth present in an animals's jaw are related to its diet. Herbivores, such as sheep, have continuously growing molars for chewing tough grass and plants. Carnivores, such as tigers, have sharp canines to kill prey and tear meat.
Mimicry- copying another animal's appearance or osunds allows a harmless organism to fool predators into thinking it is poisonous or dangerous. For example, the harmless hoverfly mimics marking of a wasp to deter predators.
80
Give some examples of behavioural adaptations.
Survival behaviours- for example, an opossum plays dead and a rabbit freezes when they think they have been seen.
Courship- many animals exhibit elaborate courthship behaviours to attract a mate. For example, scorpions perfrom a dance to attract a partner. This increases the organisms chance of reproducing.
Seasonal behaviours(migration and hibernation)- these adaptations enable organisms to cope with changes in their environment.
81
What is migration?
Animals move from one region to another, and then back again when environmental conditions are more favourable. This may be for a better climate or a source of food.
82
What is hibernation?
A period of inactivity in which an animal's body temperature, heart rate and breathing rate slow down to conserve energy, reducing the animal's requirement for food. For example, brown bears hibernate during the winter.
83
What is marram grass?
Marram grass is commonly found on sand dunes around the UK. It is a xerophyte, a plant that has adapted to live in an envionment with little water.
84
What are marram grass' adaptations?
Its adaptations reduce the rate of transpiration and include:
1. Curled leaves to minimise the surface area of moist tissue exposed to the air, and protect the leaves from the wind.
2. Hairs on the inside surface of the leaves to trap moist air close to the leaf, reducing the diffusion gradient.
3. Stomata sunk into pits, which make them less likely to open and lose water.
4. A thick waxy cuticle on the leaves and stems, reducing water loss through evaporation.
85
What are the two main categories of behavioural adaptations?
Innate(or instinctive) behaviour and learned behaviour.
86
What does the behavioural adaptation of innate behaviour mean?
The behavioural adaptation of innate behaviour is the ability to do something inhertied through genes. For example, the behaviour of spiders to build webs and woodlice to avoid light is innate. This allows the organism to survive in the habitat in which it lives.
87
What does the behavioural adaptation of learned behaviour mean?
These adaptations are learnt from experience or from observing other animals. An example of learned behaviour is the use of tools. For example, sea otters use
87
What does the behavioural adaptation of learned behaviour mean?
These adaptations are learnt from experience or from observing other animals. An example of learned behaviour is the use of tools. For example, sea otters use stones to hammer shells off rocks, and then to crack the hard shells open.
88
Give some examples of physiological adaptations.
Poison production- many reptiles produce venom to kill their prey and many plants produce poisons in their leaves to protect themselves from being eaten.
Antibiotic production- some bacteria produce antibiotics to kill other species of bacteria in the surrounding area.
Water holding- the water-holding frog can store water in its body. This allows it to survive in the desert for more than a year without access to water. Many cacti and other desert plants can hold large amounts of water in their tissues.
Other examples include reflexes, blinking, and temperature regulation.
89
What adaptations provide evidence for convergent evolution?
Anatomical adaptations
90
What is an analogous structure?
Structures that have adapted to perform the same function but have a different genetic origin.
91
When does convergent occur?
It takes place when unrelated species begin to share similar traits. These similarities evolve because the organisms adapt to similar environments or other selection pressures. The organisms, I've in a similar way to each other. Using our examples of whales and fish, their similar characteristics have evolved over time to allow the organisms to move efficiently through water.
92
Give an example of convergent evolution
Marsupials in Australia and placental mammals in the Americas are an example of convergent evolution. Species in each continent resemble each other because they have adapted to fill similar niches.
92
Give an example of convergent evolution
Marsupials in Australia and placental mammals in the Americas are an example of convergent evolution. Species in each continent resemble each other because they have adapted to fill similar niches.
