Chapter 11 - Biodiversity Flashcards
Past Paper Question - June 2018 AS2 Q4 a)i)+ii)
Q4 Biodiversity can be measured using Simpson’s Index. An investigation was carried out to assess the biodiversity of plant species in three fields. Five 1m2 quadrats were used in each field and the mean numbers of plants of five species were calculated. The results of the investigation and the calculated Simpson’s Index for two of the fields are shown in the table below.
Plant species Mean number of plants
Field A Field B Field C
common daisy 2 8 2
dandelion 1 13 1
meadow buttercup 2 9 5
white clover 8 11 15
rye grass 21 12 5
Simpson’s Index 0.43 0.19
The formula for calculating Simpson’s Index is:
ni(ni –1) N(N –1)
where N = the total number of all organisms
ni = the number of organisms of each individual species
a) (i) Using the values given and the formula above, calculate the Simpson’s Index for Field C.
(Show your working.)
Q4 a)i)
- Measuring species diversity
Sampling is often used to …
Provide information concerning biodiversity in a habitat
- Measuring species diversity
How can information concerning biodiversity in a habitat be obtained?
Sampling
- Measuring species diversity
What does biodiversity give an indication of?
Both the range of species in a habitat and also how evenly balanced the numbers of individuals are across the different species.
- Measuring species diversity
Biodiversity is not the same as …
Species richness
What is species richness?
The number of different species present in an area
What is biodiversity?
Biodiversity is a measurement of the variety of living organisms within a particular area, and has three components:
- species diversity
- ecosystem (or habitat) diversity
- genetic diversity
- Measuring species diversity
Biodiversity is not the same as species richness. A particular habitat can be …
Species-rich but not show much biodiversity.
- Measuring species diversity
Biodiversity is not the same as species richness. A particular habitat can be species-rich but not show much biodiversity, for example …
A habitat may be species-rich but has very small numbers of most species, with only one or two species dominating the community.
- Measuring species diversity
Biodiversity can be calculated by using …
Simpson’s index (D)
- Measuring species diversity
What is Simpson’s index (D)?
A measure of biodiversity that takes into account both the number of species and the number of individuals of each species.
- Measuring species diversity
Give the formula for Simpson’s index (D) and state what each variable represents
Textbook page 193
- Measuring species diversity
Biodiversity can be calculated by using Simpson’s index (D). The value of D ranges from …
1 to 0
- Measuring species diversity
Biodiversity can be calculated by using Simpson’s index (D). The value of D ranges from 1 to 0. A value of 0 represents …
Infinite biodiversity
- Measuring species diversity
Biodiversity can be calculated by using Simpson’s index (D). The value of D ranges from 1 to 0. A value of 1 represents …
No biodiversity
- Measuring species diversity
Biodiversity can be calculated by using Simpson’s index (D). The value of D ranges from 1 to 0. The lower the value of D (ie the closer to 0), the greater the …
Diversity
- Measuring species diversity
To calculate Simpson’s index, it is necessary to …
Sample the habitat to identify the number of different species present and then measure the abundance of each species.
- Measuring species diversity
To calculate Simpson’s index, it is necessary to sample the habitat to identify the number of different species present and then measure the abundance of each species. What sampling technique is typically used for animals?
Density (number)
- Measuring species diversity
To calculate Simpson’s index, it is necessary to sample the habitat to identify the number of different species present and then measure the abundance of each species. What sampling technique is typically used for plants?
Percentage cover or frequency
- Measuring species diversity
To calculate Simpson’s index, it is necessary to sample the habitat to identify the number of different species present and then measure the abundance of each species. The sampling techniques typically used for plants are percentage cover and frequency due to …
The difficulty in identifying individual plants.
- Types of diversity
Simpson’s index typically calculates …
Species diversity
- Types of diversity
Simpson’s index typically calculates species diversity, but there are other types of diversity including …
Ecosystem diversity and genetic diversity.
What are the three types of diversity?
Species diversity
Ecosystem diversity
Genetic diversity
What does the term ecosystem diversity mean?
This represents the diversity of ecosystems within the biosphere (the part of the Earth and its atmosphere that is inhabited by living organisms.
What does the term habitat mean?
- This term refers to the places where organisms live, for example, a pond or rocky shore.
- Habitats can be relatively small scale, for example, an individual leaf on a tree. These very small habitats are referred to as microhabitats.
What does the term environment mean?
- The environment describes the conditions that affect organisms in a habitat.
- The environment determines the type of habitat that can develop and also the species that can live there.
- The environment can be separated into the physical and non-living (abiotic) and the living (biotic).
- Examples of the abiotic environment include light intensity, temperature, soil conditions and wave action.
- The biotic environment includes food supply or potential predators and also organisms that can compete for resources.
- Sometimes there is overlap, for example, a tree can affect the light that is available to a seedling.
What does the term ecosystem mean?
- An ecosystem is a community of organisms, interacting with one another and the associated environment.
- An ecosystem forms a balanced self-sufficient ecological unit, with its own characteristic pattern of energy flow and nutrient cycling.
- An ecosystem can be of any size.
- Examples include forests, ponds, lakes and oceans.
What does the term population mean?
- A population is made up of all the members of the same species that occur in a particular area at a particular time.
- Examples include the world human population and the population of bluebells in a wood.
What does the term community mean?
- A community is a group of species which occur in the same place at the same time.
- A woodland community includes all the living organisms within the wood.
Give some examples of ecological terms that are interchangeable
Habitat and ecosystem
E.g. Woodland ecosystem or woodland habitat
On a worldwide scale, many major ecosystems are at risk due to …
The action of man
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of …
The melting of ice due to global warming
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by …
Land clearance
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape …
The harmful effects of the activity of man.
Name two major ecosystems that are at risk due to the action of man
North and south polar regions
Amazon rainforest
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape the harmful effects of the activity of man.
Ecosystem diversity is also an important issue on …
A more local scale
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape the harmful effects of the activity of man.
Ecosystem diversity is also an important issue on a more local scale, for example, in …
Northern Ireland
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape the harmful effects of the activity of man.
Ecosystem diversity is also an important issue on a more local scale, for example, in Northern Ireland. Much of our former ecosystem diversity has been …
Lost
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape the harmful effects of the activity of man.
Ecosystem diversity is also an important issue on a more local scale, for example, in Northern Ireland. Much of our former ecosystem diversity has been lost due to …
The intensification of agricultural practices and for other reasons
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape the harmful effects of the activity of man.
Ecosystem diversity is also an important issue on a more local scale, for example, in Northern Ireland. Much of our former ecosystem diversity has been lost due to the intensification of agricultural practices and for other reasons. Most of our …
Damp meadows and much of our hedgerow and woodland have been removed
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape the harmful effects of the activity of man.
Ecosystem diversity is also an important issue on a more local scale, for example, in Northern Ireland. Much of our former ecosystem diversity has been lost due to the intensification of agricultural practices and for other reasons. Most of our damp meadows and much of our hedgerow and woodland have been removed to …
Increase the land available for agriculture
On a worldwide scale, many major ecosystems are at risk due to the action of man. The north and south polar regions, and their communities, are at risk as a result of the melting of ice due to global warming. The Amazon rainforest ecosystem is significantly affected by land clearance. Relatively few major ecosystems escape the harmful effects of the activity of man.
Ecosystem diversity is also an important issue on a more local scale, for example, in Northern Ireland. Much of our former ecosystem diversity has been lost due to the intensification of agricultural practices and for other reasons. Most of our damp meadows and much of our hedgerow and woodland have been removed to increase the land available for agriculture. Intensively managed agricultural land does not really …
Provide a diversity of ecosystems
What is genetic diversity?
This refers to the genetic variability (diversity of genes) of the species.
Genetic variability = variation of DNA and genes
What are some of the factors that influence genetic variability?
- How long a particular species has been in existence since it has evolved.
- The degree of directional selection that has taken place in different populations.
- Species that are subject to higher rates of mutation in their DNA than other species will be more genetically variable.
Genetic variability (variation of DNA and genes) tends to be greater in species that …
Have become adapted to a wide range of environments
It is desirable that species are …
Genetically diverse
Why is it desirable that species are genetically diverse?
Genetically diverse species are more subject to directional selection and therefore are more likely to remain adapted if the environment changes.
What is classification?
Classification involves placing living organisms into groups.
The classification of organisms into groups is not …
A random process
The classification of organisms into groups is not a random process. Most classification systems take account of …
The ancestral relationships among living organisms.
What is the basic unit of biological classification?
The species
- The concept of the species
The definition of a species has changed through time. Many decades ago, organisms were categorised as being a particular species almost entirely on …
Their physical features
- The concept of the species
The definition of a species has changed through time. Many decades ago, organisms were categorised as being a particular species almost entirely on their physical features. Now, a much greater range of information is available including …
These and other features are now taken into account when determining the defining characteristics of a particular species.
Anatomy Biochemistry Physiology Immunology Genetic Ancestral development Ecology Cell structure Behaviour Life cycles
What is taxonomy?
The study of biological classification
The study of biological classification is called …
Taxonomy
Species definition
A group of individuals of common ancestry that closely resemble each other, and are normally capable of interbreeding to produce fertile offspring.
A species can be defined as:
‘A group of individuals of common ancestry that closely resemble each other, and are normally capable of interbreeding to produce fertile offspring’.
This seems straightforward but it is often very difficult to determine if a particular organism belongs to a particular species. For example, a number of large cat species have been able to interbreed in captivity (such as male tiger and lioness) and a number of the hybrid offspring (tiglon) have proved to be fertile. However, tigers and lions are still classified as separate species as …
The hybrids tend not to occur in natural conditions.
Carl Linnaeus (1707-1778), a Swedish naturalist, was the first person to make a serious attempt at classification. He devised the …
Binomial system
The binomial system gives each species …
Two names
The binomial system gives each species two names. The first name is the …
Generic name, which indicates the genus (plural genera) to which the species belongs.
The binomial system gives each species two names. The second name is the …
Specific or species names, which identifies the species to which the organism belongs.
There are a number of conventions concerning binomial names. The system is used …
Worldwide
There are a number of conventions concerning binomial names. The system is used worldwide and the names are usually derived from …
Latin or Greek.
There are a number of conventions concerning binomial names. The system is used worldwide and the names are usually derived from Latin or Greek. They are always printed in …
Italics
There are a number of conventions concerning binomial names. The system is used worldwide and the names are usually derived from Latin or Greek. They are always printed in italics with the genus name starting with a …
Capital.
There are a number of conventions concerning binomial names. The system is used worldwide and the names are usually derived from Latin or Greek. They are always printed in italics with the genus name starting with a capital. When used more than once in a sentence …
The generic name can be shortened to the first letter, followed by a full stop.
The arrangement of organisms into groups is known as …
Classification
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve …
The organisation of species into hierarchical groups of increasing size.
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a …
Taxon
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a taxon (plural …).
Taxa
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a taxon (plural taxa). The groups (in increasing size) are …
Species Genus Family Order Class Phylum Kingdom
Keep Pond Clean Or Frogs Get Sick
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a taxon (plural taxa). The groups (in increasing size) are species, genus, family, order, class, phylum and kingdom. Consequently, the number of species in each classification group …
Increases as the sub-sets become larger.
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a taxon (plural taxa). The groups (in increasing size) are species, genus, family, order, class, phylum and kingdom. Consequently, the number of species in each classification group increases as the sub-sets become larger.
The taxonomic system can be …
Sub-divided into sub-categories
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a taxon (plural taxa). The groups (in increasing size) are species, genus, family, order, class, phylum and kingdom. Consequently, the number of species in each classification group increases as the sub-sets become larger.
The taxonomic system can be sub-divided into sub-categories. Many species have …
Sub-species
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a taxon (plural taxa). The groups (in increasing size) are species, genus, family, order, class, phylum and kingdom. Consequently, the number of species in each classification group increases as the sub-sets become larger.
The taxonomic system can be sub-divided into sub-categories. Many species have sub-species where, …
Although all the member of the species fit the species definition, two or more populations may be distinct enough to form distinct groupings or sub-species.
- Taxonomy
The arrangement of organisms into groups is known as classification and the science or study of classification is called taxonomy. There are many systems of classification but they all involve the organisation of species into hierarchical groups of increasing size. Each group is called a taxon (plural taxa). The groups (in increasing size) are species, genus, family, order, class, phylum and kingdom. Consequently, the number of species in each classification group increases as the sub-sets become larger.
The taxonomic system can be sub-divided into sub-categories. Many species have sub-species where, although all the member of the species fit the species definition, two or more populations may be distinct enough to form distinct groupings or sub-species.
Give an example of this.
The ‘grizzly’ bear is a sub-species of the brown bear
The sub-species name is usually added …
To the end of the species name
Name all seven taxon
Kingdom Phylum Class Order Family Genus Species
Give a definition of the taxon ‘genus’
A group of similar and closely related species.
Give a definition of the taxon ‘family’
A group of related genera.
Give a definition of the taxon ‘order’
A group of related families
Give a definition of the taxon ‘class’
A group of related orders
Give a definition of the taxon ‘phylum’
A group of related classes (a group of organisms constructed on a similar plan).
Give a definition of the taxon ‘kingdom’
A group of related phyla
Taxonomy involves both …
Nomenclature and systematics
What is nomenclature?
The scientific naming of organisms using the binomial system
What is systematics?
The placing of organisms into groups based on their similarities and differences
Taxonomy involves both nomenclature (the scientific naming of organisms using the binomial system) and systematics (the placing of organisms into groups based on their similarities and differences). Recent taxonomic systems attempt to classify species and the larger organisms based on …
Their ancestral relationships
Taxonomy involves both nomenclature (the scientific naming of organisms using the binomial system) and systematics (the placing of organisms into groups based on their similarities and differences). Recent taxonomic systems attempt to classify species and the larger organisms based on their ancestral relationships, rather than …
Just a superficial accumulation of similarities.
Phylogenetic taxonomy is also referred to as …
Phylogeny
Phylogeny is also referred to as …
Phylogenetic taxonomy
What is phylogenetic taxonomy (phylogeny)?
The process of classification of species and larger groups according to their ancestral relationships
Phylogenetic taxonomy (phylogeny) is the process of the classification of species and larger groups according to their ancestral relationships. In effect, the different species in a genus do not just have …
A large number of similarities
Phylogenetic taxonomy (phylogeny) is the process of the classification of species and larger groups according to their ancestral relationships. In effect, the different species in a genus do not just have a large number of similarities, they also share …
Common ancestry, i.e. they have evolved from a common ancestor.
Phylogenetic taxonomy (phylogeny) is the process of the classification of species and larger groups according to their ancestral relationships. In effect, the different species in a genus do not just have a large number of similarities, they also share common ancestry, ie they have evolved from a common ancestor. Groups of species that have shared a common ancestor more recently than other species will consequently be …
More closely related
Why is phylogenetic taxonomy now a much more scientific process?
Due to a greater understanding of the evolutionary development of life on Earth.
Additionally, there is exponential progress in the techniques available to elucidate relationships among organisms at the microscopic and biochemical level, as well as more obvious physical and behavioural characteristics of organisms.
What are the techniques that are used to establish phylogeny?
Morphology and anatomy (external and internal features)
Cell structure
Biochemistry
What is morphology?
Morphology refers to the external features of an organism (for example, the presence of four limbs)
What is anatomy?
Anatomy refers to the internal features of an organism (for example, the presence of a backbone).
Morphology and anatomy - Morphology refers to the external features of an organism (for example, the presence of four limbs) and anatomy the internal features (for example, the presence of a backbone). Historically, these have been very important in …
The early classification systems.
Morphology and anatomy - Morphology refers to the external features of an organism (for example, the presence of four limbs) and anatomy the internal features (for example, the presence of a backbone). Historically, these have been very important in the early classification systems. They are still important and can often be readily and easily used to …
Classify organisms and show relationships.
Morphology and anatomy - Morphology refers to the external features of an organism (for example, the presence of four limbs) and anatomy the internal features (for example, the presence of a backbone). Historically, these have been very important in the early classification systems. They are still important and can often be readily and easily used to classify organisms and shows relationships. A good example is the …
Vertebrate ‘pentadactyl’ limb
What is the vertebrate pentadactyl limb?
The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers.
The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers. This similarity shows that …
All vertebrates are related and have common ancestry, even though the limbs have evolved into a wide range of structures that look very different and have very different functions.
The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers. This similarity shows that all vertebrates are related and have common ancestry, even though the limbs have evolved into a wide range of structures that look very different and have very different functions.
Nonetheless, the presence of a modified form of ‘pentadactyl’ limb clearly identifies the different species as a member of …
The Phylum Chordata (vertebrates)
The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers. This similarity shows that all vertebrates are related and have common ancestry, even though the limbs have evolved into a wide range of structures that look very different and have very different functions.
Nonetheless, the presence of a modified form of ‘pentadactyl’ limb clearly identifies the different species as a member of the Phylum Chordata (vertebrates).
However, appearances can be …
Misleading
The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers. This similarity shows that all vertebrates are related and have common ancestry, even though the limbs have evolved into a wide range of structures that look very different and have very different functions.
Nonetheless, the presence of a modified form of ‘pentadactyl’ limb clearly identifies the different species as a member of the Phylum Chordata (vertebrates).
However, appearances can be misleading. Bats and birds have wings that can look very similar in some species. While the two groups belong to the Phylum …
Chordata
The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers. This similarity shows that all vertebrates are related and have common ancestry, even though the limbs have evolved into a wide range of structures that look very different and have very different functions.
Nonetheless, the presence of a modified form of ‘pentadactyl’ limb clearly identifies the different species as a member of the Phylum Chordata (vertebrates).
However, appearances can be misleading. Bats and birds have wings that can look very similar in some species. While the two groups belong to the Phylum Chordata (they have the characteristic features of the vertebrates, including the pentadactyl limb), they are …
Not as closely related as their morphology suggests.
The pentadactyl limb is the basic unit upon which the many forms of vertebrate limb have evolved, including legs, arms, wings and flippers. This similarity shows that all vertebrates are related and have common ancestry, even though the limbs have evolved into a wide range of structures that look very different and have very different functions.
Nonetheless, the presence of a modified form of ‘pentadactyl’ limb clearly identifies the different species as a member of the Phylum Chordata (vertebrates).
However, appearances can be misleading. Bats and birds have wings that can look very similar in some species. While the two groups belong to the Phylum Chordata (they have the characteristic features of the vertebrates, including the pentadactyl limb), they are not as closely related as their morphology suggests. Why is this?
As birds have wings with feathers whereas the bat wing is an extension of the skin. They have superficially similar morphologies but very different ancestries, as birds belong to the Class Aves and bats to the Class Mammalia.
Phylogenetic taxonomy (phylogeny) The techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Cell structure
The key difference in cell structure is whether the organism in question is …
Prokaryotic or eukaryotic
Phylogenetic taxonomy (phylogeny) The techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Cell structure
The key difference in cell structure is whether the organism in question is prokaryotic or eukaryotic. The first cells were …
Prokaryotic
Phylogenetic taxonomy (phylogeny) The techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Cell structure
The key difference in cell structure is whether the organism in question is prokaryotic or eukaryotic. The first cells were prokaryotic and for many millions of years life on Earth was entirely …
Prokaryotic
Phylogenetic taxonomy (phylogeny) The techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Cell structure
The key difference in cell structure is whether the organism in question is prokaryotic or eukaryotic. The first cells were prokaryotic and for many millions of years life on Earth was entirely prokaryotic. Eventually, …
Eukaryotic cells evolved and four out of five kingdoms in the most common classification system used today are eukaryotic.
With the split between prokaryotic and eukaryotic organisms taking place very early in the development of life on Earth, this means that the organisms in the four eukaryotic kingdoms (Protoctista, Plantae, Fungi and Animalia) are …
More closely related to each other than they are to organisms in the kingdom Prokaryotae
Phylogenetic taxonomy (phylogeny) The techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Cell structure
The key difference in cell structure is whether the organism in question is prokaryotic or eukaryotic. The first cells were prokaryotic and for many millions of years life on Earth was entirely prokaryotic. Eventually, eukaryotic cells evolved and four out of five kingdoms in the most common classification system used today are eukaryotic.
With the split between prokaryotic and eukaryotic organisms taking place very early in the development of life on Earth, this means that the organisms in the four eukaryotic kingdoms (Protoctista, Plantae, Fungi and Animalia) are more closely related to each other than they are to the organisms in the kingdoms Prokaryotae.
Cell structure is also important in …
Classifying other groups. Cell structural differences are important in classifying organisms as plants, fungi or animals.
Phylogenetic taxonomy (phylogeny)
Techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Biochemistry
In recent years, biochemistry has has become …
Increasingly important in classification.
Phylogenetic taxonomy (phylogeny)
Techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Biochemistry
In recent years, biochemistry has has become increasingly important in classification. In the last decade or so, it has been possible to …
Analyse the genomes (complete DNA map) of species.
Phylogenetic taxonomy (phylogeny)
Techniques used to establish phylogeny include morphology and anatomy, cell structure and biochemistry.
- Biochemistry
In recent years, biochemistry has has become increasingly important in classification. In the last decade or so, it has been possible to analyse the genomes (complete DNA map) of species. Almost always, genome analysis and other biochemical techniques have …
Confirmed the phylogenetic relationships already established by more traditional methods, but occasionally they have resulted in species taking up a new position in classification systems.
The biochemical basis of life is …
Similar in all organisms
The biochemical basis of life is similar in all organisms. They all contain …
Carbohydrates
Lipids
Nucleic acids
Proteins
The biochemical basis of life is similar in all organisms. They all contain carbohydrates, lipids, nucleic acids and proteins. The more closely related species are, …
The more similar their DNA will be.
The biochemical basis of life is similar in all organisms. They all contain carbohydrates, lipids, nucleic acids and proteins. The more closely related species are, the more similar their DNA will be. DNA codes for …
The amino acid sequence in a protein through the medium of mRNA
The biochemical basis of life is similar in all organisms. They all contain carbohydrates, lipids, nucleic acids and proteins. The more closely related species are, the more similar their DNA will be. As DNA codes for the amino acid sequence in a protein brought the medium of mRNA, it follows that …
The more closely related species are, the more similarities their RNA and protein sequences will be.
Once two or more species (or groups) evolve from …
An ancestral species
Once two or more species (or groups) evolve from an ancestral species, …
Certain mutations will spontaneously take place in the DNA of one of the species but not necessarily in the other(s).
Once two or more species (or groups) evolve from an ancestral species, certain mutations will spontaneously take place in the DNA of one of the species but not necessarily in the other(s). Over time the species will …
Increasingly differ in their DNA (and RNA and amino acid sequence in proteins
Once two or more species (or groups) evolve from an ancestral species, certain mutations will spontaneously take place in the DNA of one of the species but not necessarily in the other(s). Over time the species will increasingly differ in their DNA (and RNA and amino acid sequences in proteins). The relationships among species and the length of time since they shared a common ancestor, can be evaluated through …
Analysing similarities in DNA, RNA or protein, using the degree of change at gene or biochemical level as a type of molecular clock.
What is the current classification system recognised by many scientists?
The five kingdom classification system
How many kingdoms does the current model recognise?
5
What are the five kingdoms recognised by the current model of classification?
Prokaryotae Protoctista Fungi Plantae Animalia
What does the five kingdom system suggest?
The five kingdom system suggests that there are three overarching levels of organisation.
The five kingdom system suggests that there are three overarching levels of organisation. What are the three levels of organisation?
(In increasing level)
• Prokaryotic
- Kingdom Prokaryotae
• Eukaroyotic unicellular
- Kingdom Protoctista
- Mainly unicellular or multicellular showing limited differentiation
• Eukaryotic multicellular
- Kingdom Fungi, Plantae and Animalia
- Multicellular eukaryotes (with the exception of some unicellular fungi)
(Bottom of textbook page 200)
Describe kingdom Prokaryotae
- Prokaryotae occur as single cells, clusters or ‘strings’ of cells stuck together.
- Organisms in the kingdom Prokaryotae have prokaryotic cells.
- Prokaryotic cells are:
- Without a nucleus or membrane-bound organelles.
- DNA lies free in the cytoplasm and is not organised into chromosomes.
- Ribosomes are smaller than in eukaryotic cells (20 nm (70S)).
- Cell walls are present but are made of peptidoglycans.
- No microtubules.
- Cell division occurs by binary fission (splitting into two without meiosis).
Give two examples of prokarotae
Bacteria
Blue-green algae
Typical ‘rod shaped’ bacteria are …
Prokaryotes
Describe kingdom Protoctista
- Protoctistans are eukaryotic unicellular or multicellular. If multicellular, they have limited differentiation into different tissues.
- This is a very diverse group and to some extent it operates as a ‘bin’ including those organisms that do not fit into the other kingdoms.
- Many species are unicellular but many others are organised into filaments with cells joined end to end in a long thread like structure or are multicellular.
- If multicellular, they have limited differentiation. - Some are autotrophic and photosynthesise.
- Protoctistans in this phylum have typical ‘plant’ cells with cellulose cell walls and chlorophyll but are not classified in the kingdom Plantae as they are often unicellular (or filamentous or cell aggregates) and not true multicellular forms. - Some unicellular protoctista are heterotrophic, ingesting and digesting their food.
- They are not classified as animals as they are unicellular.
Give an example of a protoctistan that feeds heterotrophically
Paramecium
Describe the structure of a paramecium cell, a protoctistan that feeds heterotrophically
- Cilia for locomotion
- Digestive vacuoles containing ingested bacteria
- Contractile vacuoles for water regulation
- Nucleus
Textbook page 201
Draw a diagram of Fucus vesiculosus (bladderwrack), a brown seaweed
Textbook page 201
Describe kingdom Fungi
- Fungi are eukaryotic but can be unicellular (for example, yeast) or multicellular (most fungi).
- Although multicellular, fungi are often organised as hyphae (long filaments which together form the mycelium, the hyphal network).
- The elongated hyphal strands, characteristic of fungi, are frequently multinucleate and not clearly divided into separate cells.
- They have a cell wall made of chitin (not cellulose as in plants).
- Fungi have a lysotrophic or saprophytic mode of nutrition. They feed by decomposing organic matter.
- They secrete hydrolytic enzymes into the soil by exocytosis and after the enzymes have digested the organic material in the soil (for example, dead roots), they absorb the products of digestion.
- As their enzymes work outside the cell this is called extracellular digestion.
- Fungi store carbohydrates as glycogen.
- Fungi are important decomposers, crucial in the breakdown and recycling of organic matter.
- They are very common in woodland where they are particularly important in decomposing plant material, including wood.
- Examples include moulds (such as blue mould), mushrooms and toadstools.
Draw a diagram showing the process of extracellular digestion in fungi
Textbook page 202
What are toadstools and mushrooms?
The toadstool and mushroom are specialised fungal reproductive structures. These structures are raised above ground to facilitate the release and dispersal of spores.
Describe kingdom Plantae
- Plants are multicellular eukaryotes that exhibit autotrophic nutrition (photosynthesise and make complex organic materials from simple inorganic raw materials).
- They possess chlorophyll in chloroplasts and have a cellulose cell wall.
- They store carbohydrates as starch and lipids as oils.
- Examples include mosses, ferns, conifers and flowering plants.
Describe kingdom Animalia
- Animals are multicellular eukaryotes that feed heterotrophically (by consuming organic food).
- A key difference between animals and fungi is that an animal takes in its food then digests it, whereas fungi digest their food before taking it in.
- Animal cells do not possess a cell wall.
- Animals store carbohydrates as glycogen and lipids as fats.
- Most are capable of locomotion.
- Examples include flatworms, insects and chordates (fish, amphibians, reptiles, birds and mammals).
- Alternative classification systems
As knowledge of the relationships among organisms increases due to …
Better knowledge of biochemistry and cell biology
- Alternative classification systems
As knowledge of the relationships among organisms increases due to better knowledge of biochemistry and cell biology, scientists continue to …
Evaluate how organisms should be classified.
- Alternative classification systems
As knowledge of the relationships among organisms increases due to better knowledge of biochemistry and cell biology, scientists continue to evaluate how organisms should be classified. Many scientists now think that …
All living organisms can be grouped into three super-kingdoms or domains
- Alternative classification systems
As knowledge of the relationships among organisms increases due to better knowledge of biochemistry and cell biology, scientists continue to evaluate how organisms should be classified. Many scientists now think that all living organisms can be grouped into three super-kingdoms or domains, these being …
The archaea, bacteria and eukarya
Both the archaea and bacteria are …
Prokaryotes
Describe the similarities and differences between archaea and bacteria
Similarities
- Both are prokaryotic (ie lack membrane-bound organelles and have a circular DNA molecule).
- Similar in appearance
Differences
- Archaea are similar to bacteria in appearance but very different biochemically.
- DNA replication, genetics and metabolic pathways are very different in the two groups.
- For example, some species of archaea can produce methane but bacteria cannot.
- The archaea includes species that are highly adapted for living in ‘extreme’ environments such as in very high temperatures or in very salty water.
- In reality, in terms of biochemistry if not appearance, there is as much difference between the bacteria and the archaea as there is between either and the eukaryotes.
- Archaea and Eukarya lack a peptidoglycan cell wall (though many Eukarya have no cell wall) and have histones (proteins) bound to the DNA. (ie bacterial DNA is ‘naked’).
- Archaea membranes contain phospholipids that differ from those of Bacteria and Eukarya.
Draw a diagram showing the hierarchal order of living organisms in the alternative classification system known as the three domain system
Textbook page 204
The alternative classification system is often referred to as …
The three domain system
How do scientists think the first eukaryotic cell arose?
Some scientists think that the first eukaryotic cell arose as a result of a chance fusion between an archaeon host cell and a smaller bacterial cell.
Knowledge check 42
A biologist wished to determine whether the members of two populations belonged to the same species. How could this be achieved?
Test whether they can interbreed successfully and produce fertile offspring.
Knowledge check 43
Why is it important for scientists to use Latin names, rather than common names, for organisms mentioned in research papers?
The Latin names are used internationally and are understood by scientists worldwide, whereas common names can differ locally let alone internationally.
Knowledge check 44
Describe the differences between plants and fungi.
Plants are autotrophic (photosynthetic), containing chloroplasts with chlorophyll, while fungi are heterotrophic (lysotrophic).
Plants are multicellular, while fungi may be unicellular, though most are multicellular.
Plants store carbohydrates as starch, while fungi store carbohydrates as glycogen.
Plant cells have a cellulose cell wall, while fungi have cell walls made of chitin.
Knowledge check 45
Name one characteristic in each of the following kingdoms:
a) fungi
b) animals
a) Chitin cell wall/cells are organised into hyphae.
b) Animal cells never have a cell wall; they store lipids as fats.
Knowledge check 46
Apart from being eukaryotic, identify two features that fungi and animals have in common.
Both are heterotrophic and store carbohydrates as glycogen.
Knowledge check 47
DNA from two species was hybridised. The two strands separated at very low temperature. Explain what this tells us about the two species.
The two species are not closely related.
Separation at low temperature indicates that there are few hydrogen bonds holding the two strands together.
This means that there are many bases in the hybrid DNA that are not complementary - for example if the bases C and A come together during hybridisation, they will not form a hydrogen bond.
Knowledge check 48
Seed banks contain seeds of the ancestors of modern crop plants. Suggest why these seeds are kept.
Seed banks maintain a source of genetic diversity for crop plants. They contain genes that could confer subtle variations, such as resistance to drought, frost or pests (which modern plants may lack, having been selected for increased yield).
Autotrophic definition
Producing its own food (carbohydrates, fats and proteins) from simple inorganic substances, general using light energy in photosynthesise.
Heterotrophic definition
Obtaining food by digestion of complex organic compounds (polysaccharides, fats and proteins); lysotrophic is one type of heterotrophic nutrition.
What is species diversity?
The diversity among species in an ecosystem
Species diversity is measured using …
Simpson’s index
Give some examples of organisms belonging to kingdom Prokaryotae
Bacteria
Blue-green algae (cyanobacteria)
Hot-spring bacteria (belonging to the Archaea domain)
Give some features of kingdom Prokaryotae
- Cells are microscopic and prokaryotic: they lack a nucleus and membrane-bound organelles.
- The DNA is circular (and not histone-bound in bacteria
- Ribosomes are smaller than those in eukaryotes
- Cell walls are made of peptidoglycan in bacteria (but not in archaebacteria).
- Since nuclei are lacking, cell division occurs by simple binary fission.
- Different methods of nutrition are exhibited by the prokaryotes.
Give some features of kingdom Protoctista
- This is a diverse group and membership is often by exclusion from all other groups.
- Some are unicellular, some are filamentous while others are multicellular, though show limited differentiation.
- All protoctistans have eukaryotic cells.
- Some possess cell walls (cellulose or non-cellulose) and chlorophyll (enabling photosynthesis), while others have no cell walls and are motile.
- They can be autotrophic or heterotrophic.
Give some features of kingdom Fungi
- Fungi are most often unicellular, though a few are unicellular (e.g. yeast).
- Cells are eukaryotic (most often organised into filaments, or hyphae, and frequently multinucleate and not divided into separate cells).
- Cells have a cell wall, often made of chitin.
- Fungi have a lysotrophic method of nutrition: they secrete enzymes to digest organic materials (usually dead) outside their cells (extracellular digestion) and absorb the products of digestion.
- They are important decomposers, breaking down and recycling organic matter.
- They store carbohydrates as glycogen, and lipids as oil.
Give some features of kingdom Plantae
- Multicellular.
- Cells are eukaryotic.
- Cells possess a cellulose cell wall.
- All plants are photosynthetic, containing chlorophyll in chloroplasts, and are autotrophic.
- They store carbohydrates as starch, and lipids oils.
Give some features of kingdom Animalia
- Multicellular.
- Cells are eukaryotic.
- Cells lack a cell wall.
- All animals are heterotrophic; most ingest food into a digestive system.
- They store carbohydrates as glycogen, and usually store lipids as fats.
- Most are capable of locomotion.
The basic unit of biological classification is …
The species
Species are named using their genus and species. This is called the binomial system.
If the species is not certain but the genus is known, it is possible to refer to an organism …
By the name of the genus followed by ‘sp.’ (plural ‘spp.’)
The basis for the three-domain system is, in the main, due to …
Unique differences in the RNA molecules in ribosomes
