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Advanced Higher Unit 2Organisms and Evolution Field techniques for biologists Field techniques introduction • This section of the course and your Project will be based around environmental biology. • To begin- Why would biologists study an ecosystem? THINK, PAIR AND SHARE • Think and discuss a partner for 1 minute. • Share your ideas with the rest of the class. Ideas? • To monitor susceptible or endangered species. • To assess the effects of pollution, intensive farming, habitat destruction and other human influences on populations. • To assess the effects of hunting and fishing on wild populations. • To monitor levels of food species (eg fish) and species used as raw materials for humans. • To monitor abundance and biodiversity. • Find new species. Field techniques • Many factors can be measured within an ecosystem, so; • What do we need to measure? • Living organisms-plants, animals (biotic) • pH, temperature, wind speed, moisture, light intensity, pollution (abiotic) • How are they measured? • Sampling! Field techniques • So why sample? • How many pink flowers are in the field? • Without counting them all you’ll never know. Field techniques • Sampling will allow you to know what kind of plants and animals are in a particular habitat without having to count every single one. • Your sampling strategy therefore has to be efficient and cover enough area to give a good representation of your habitat. • Include both abiotic and biotic factors so you can determine any relationships, differences in areas or changes over time. Sampling techniques • How do we sample? • Biotic (living) factors• • • • • • • Quadrats- grasslands/lichens, Capture techniques eg pitfall traps, Sweep nets, Camera traps, Scat sampling, Kick sampling, Tree beating. Quadrats Pitfall traps Tree beating Scat sampling Sweep netting Kick sampling Sampling techniques • Abiotic (non-living) factors• soil samples, pH meters, moisture meters, thermometers, anemometers, oxygen probes, humidity, water velocity. • All samples that are taken have to be appropriate to the aim of your investigation. Examples of equipment used to measure light intensity, wind speed, oxygen concentration, humidity and temperature Sampling techniques- example Sampling plants: • Numbers (abundance) of plants per unit area • % cover of plants • Height of plants • Leaf size / stem height / internode length • Yield of seeds/fruits over time • Species diversity What equipment is needed for this? • Quadrat (what size?) • Ruler / metre stick • Plant ID key Sampling techniques-example Sampling animals • Numbers (abundance) of animals (how easy is this?) • Species diversity • What equipment is needed for this? • Animal ID key • Method to collect / trap animals? • Techniques include pitfall traps, tree beating, sweep nets, leaf litter scraping Getting your samples A) Health and Safety (a) Health and Safety what you need to know • Fieldwork may involve a wider range of hazards compared with working in the laboratory. • Hazards and risks associated with terrain, weather conditions and isolation must be assessed. Hazards and ethics • Fieldwork, unlike lab work, means that you are observing not controlling the environment so there may be a wider range of hazards compared with working in the laboratory. • There are some essential considerations regarding hazards and risks. Health and safety • What are some of the risks associate with fieldwork? • • • • Terrain Weather conditions Exposure Isolation • How can we minimise these risks? • Risk assessment • Take precautions • Work in a safe, sensible manner Risk assessment • Risk assessments should be carried out before any fieldwork so you are aware of the hazards and how to minimise them. • You have to consider the likelihood of the hazard occurring (low, medium, high), how you can control it and the likelihood of it occurring after your control mechanism. • All hazards should be low after control mechanism, otherwise it is not safe to work. Risk assessment • Activity- work with your partner and try to complete the risk assessment sheet for the following scenario. • You are looking to investigate pollution in the White Cart. You’ll be working in the river, around a sewage outflow pipe. You’ll be taking water samples and doing kick sampling. • What are the risks and how do you minimise them? Risk assessment Activity:________________________ Hazard Likelihood of occurrence Severity Location:_____________________________ Control mechanism Likelihood of occurrence after control Risk assessment Activity:________________________ Hazard Drowning Exposure to cold Infections from pollution Location:_____________________________ Likelihood of occurrence Medium Severity Control mechanism High Low Medium Medium Medium Always work within view of others. Wear suitable footwear to avoid slipping. Never work in water deeper than half a wellington boot Wear suitable warm clothes. Change clothes if wet. Wear rubber gloves at all times. Wash hands thoroughly once finished. Do not consume food and drink while working in river. Likelihood of occurrence after control Low Low Low (a) Health and Safety what you need to know • Fieldwork may involve a wider range of hazards compared with working in the laboratory. • Hazards and risks associated with terrain, weather conditions and isolation must be assessed. b) Sampling of wild organisms what you need to know • Sampling should be carried out in a manner that minimises impact on wild species and habitats. • Consideration must be given to rare and vulnerable species and habitats, which are protected by legislation. • The chosen technique such as point count, transect or remote detection must be appropriate to the species being sampled. • Quadrats of suitable size and shape are used for sessile and slow-moving organisms; capture techniques for mobile species. • Elusive species can be sampled directly using camera traps or an indirect method such as scat sampling. • Sampling should be carried out in a manner that minimises impact on wild species hand habitats. • Consideration must be given to rare and vulnerable species and habitats, which are protected by legislation. Quadrats • Quadrats of suitable size and shape are used for sessile and slow-moving organisms. Transects • Capture techniques are used for mobile species. • These include– Pitfall traps – Nets – Remote detection-Camera traps and Scat sampling (for elusive species) Activity • Write your own notes on the following sampling techniques using your pupil notes: – – – – – Point count Transect Quadrats Camera traps Scat sampling b) Sampling of wild organisms what you need to know • Sampling should be carried out in a manner that minimises impact on wild species and habitats. • Consideration must be given to rare and vulnerable species and habitats, which are protected by legislation. • The chosen technique such as point count, transect or remote detection must be appropriate to the species being sampled. • Quadrats of suitable size and shape are used for sessile and slow-moving organisms; capture techniques for mobile species. • Elusive species can be sampled directly using camera traps or an indirect method such as scat sampling. c) Identifying your samples • • • • • • c) Identifying your samples what you need to know Identification of a sample can be made using classification guides, biological keys or analysis of DNA or protein. Familiarity with taxonomic groupings allows predictions and inferences to be made between the biology of an organism and better-known (model) organisms. Genetic evidence reveals relatedness obscured by divergent or convergent evolution. Life is classified into three domains, the archaea, bacteria and eukaryota. The plant kingdom has major divisions such as mosses, liverworts, ferns, conifers and flowering plants. The animal kingdom is divided into phyla, which include the Chordata Arthropoda, Nematoda, Platyhelminthes and Mollusca. c) Identifying your samples what you need to know • Model organisms from within all taxonomic groups are used to obtain information that can be applied to species that are more difficult to study directly. • Model organisms that have been very important in the advancement of modern biology include the bacterium E. coli; the flowering plant Arabidopsis thaliana; the nematode C. elegans; the arthropod Drosophila melanogaster and mice, rats and zebrafish which are chordates. • The classification of life according to relatedness is central to biological understanding. Identification and Taxonomy • During your investigation you’ll be sampling areas and identifying various organisms. • Identification can be done using classification guides, biological keys or DNA/protein analysis. • How we classify organisms comes from Taxonomy- the branch of science concerned with the classification of organisms. • How do we classify organisms? • What are taxonomic groups? Classification of life Identification • In the field, identification of a sample can be made using classification guides and biological keys, or observations and data that can be used with these and later recorded. • Lab techniques can also be used in identification. Analysis of DNA or protein can be used. This can be particularly useful where visual identification is not clear and differences are at a cellular level. Model organisms • Familiarity with taxonomic groupings allows predictions and inferences to be made between the biology of an organism and better-known (model) organisms. • Model organisms are those that scientists already know a lot about and have been studying for many years. • Organisms such as E. Coli, drosophila, yeast, maize, mice and zebrafish are all good examples of model organisms from different taxonomic groups. • Sometimes, organisms may appear more or less related than they actually are due to convergent and divergent evolution respectively. • Genetic evidence is often used to dispel myths regarding relatedness. • It was recently used to show that red pandas are more closely related to racoons rather than the former theory, which suggested greater relatedness to the giant panda. The closest living relative to the elephant- the hyrax Divergent evolution • Organisms evolve and share a common ancestor. Convergent evolution • Convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. Taxonomy • Taxonomy means classification. • In Biology this means the name we give to a species. • Taking the tiger as an example: Taxonomy • Life can be classified into 3 domains- archaea, bacteria and eukaryota •Archaea- prokaryotic, often thought of as bacteria but distinct evolution from bacteria. •Bacteria- prokaryotic contains many common examples- e.coli •Eukaryota- eukaryotes, plant and animal kingdom under this domain The three domains of life Taxonomy • The plant kingdom has major divisions including mosses, liverworts, ferns, conifers and flowering plants. •The animal kingdom has phyla including •Chordata (sea squirts /vertebrates) •Arthropoda (jointed invertebrates) •Nematoda (round worms) •Platyhelminths (flat worms) •Mollusca Taxonomy- example •Some classifications contain sub-orders or sub- families depending on the organism and detail of classification. •Human taxonomy•Eukaryota •Animalia •Chordata •Mammalia •Primates •(Haplorhini) •Hominidae •Homo •H. sapiens Taxonomy-example •E.coli•Domain: Bacteria •Phylum: Proteobacteria •Class: Gammaproteobacteria •Family: Enterobacteriaceae •Genus: Escherichia •Species: E. coli Taxonomy-example • White Daffodil •Kingdom: Plantae •Phylum: Angiosperms •Class: Monocots •Order: Asparagales •Family: Amaryllidaceae •Subfamily: Amaryllidoideae •Genus: Narcissus •Species: N. poeticus Taxonomy •The related nature shown by taxonomic groups, allows scientists to study model organisms. •It’s easier to test drugs/diets/genetic diseases in mice than humans! Activity 1 Use your notes and the Scholar Study Guides to describe all of the divisions of the plant and animal kingdom. Activity 2 Activity 2 • • • • • • c) Identifying your samples what you need to know Identification of a sample can be made using classification guides, biological keys or analysis of DNA or protein. Familiarity with taxonomic groupings allows predictions and inferences to be made between the biology of an organism and better-known (model) organisms. Genetic evidence reveals relatedness obscured by divergent or convergent evolution. Life is classified into three domains, the archaea, bacteria and eukaryota. The plant kingdom has major divisions such as mosses, liverworts, ferns, conifers and flowering plants. The animal kingdom is divided into phyla, which include the Chordata Arthropoda, Nematoda, Platyhelminthes and Mollusca. c) Identifying your samples what you need to know • Model organisms from within all taxonomic groups are used to obtain information that can be applied to species that are more difficult to study directly. • Model organisms that have been very important in the advancement of modern biology include the bacterium E. coli; the flowering plant Arabidopsis thaliana; the nematode C. elegans; the arthropod Drosophila melanogaster and mice, rats and zebrafish which are chordates. • The classification of life according to relatedness is central to biological understanding. d) Monitoring Populations d) Monitoring Populations what you need to know • Presence, absence or abundance of indicator species can give information of environmental qualities, such as presence of pollutant. • Mark and recapture is a method for estimating population size. A sample of the population is captured and marked (M) and released. After an interval of time, a second sample is captured (C). If some of the individuals in this second sample are recaptures (R) then the total population N = (MC)/R, assuming that all individuals have an equal chance of capture and that there is no immigration or emigration. • Methods of marking include banding, tagging, surgical implantation, painting and hair clipping. • The method of marking and subsequent observation must minimise the impact on the study species. • Classification of vegetation types is based on indicator species within the community structure. • Monitoring populations; their presence, absence or abundance can be used to give information of environmental qualities, such as presence of pollutant. • Understanding the tolerances of a particular species means you can use them as indicators for the environment and for the community. • e.g. Lichens and air quality (in particular SO2 pollution). Mark and capture activity • • • • ‘Capture’ a sample from the box. Mark them using a felt-tip pen. Return the sample and ‘capture’ another sample. Record the number of recaptures and use the equation to get a total population size. • N= (MC)/R • How accurate is it? • Does the sample size need to be the same each time? Monitoring Populations • Mark and recapture is a method for estimating population size. • A sample of the population is captured and marked (M) and released. A second sample is captured (C). If some of the individuals in this second sample are recaptures (R) then the total population N = (MC)/R. • The method of marking and subsequent observation must minimise the impact on the study species. • Methods of marking include banding, tagging, surgical implantation, painting and hair clipping. Banding • Often metal, bands with an individual identifier are attached to the animal where it will not impede their movement. • If it will not be possible or appropriate to physically recapture different colours of bands or sequences of colour bands can be used for remote identification (e.g. through binoculars) • Often used on birds, attached to the leg. • e.g. penguin chicks are tagged early to track their colony. Tagging • Tags will vary according to the species you are tracking. The tag is used for remote tracking e.g. radio transmitters. • The tag has to be securely attached, but also not interfere with the animals normal behaviour. • e.g. transmitters attached to turtle shells. Surgical Implantation • Tags can be implanted to prevent them interfering with the animal. For example, external tags on fish make a large difference to their streamlining • Since the animal undergoes a surgical procedure there are implications for their welfare and for the expertise required. • e.g. tracking striped bass. Painting • Non-toxic, biodegradable paints must be used. Care must also be taken that the paint does not blog skin surfaces for heat regulation, secretion or respiration. • It is also important to consider the impact of scent and colour marking on animals. • e.g. hedgehogs in Guernsey. Hair Clipping • A clearly identifiable section of hair removed can be used as very effective method of identification. • Care has to be taken regarding; size of clipping, distress to animal, social signals with animals. • e.g. tracking mice in field studies • (HINT: COMMON EXAM QUESTION) Some assumptions in this method include; -all individuals have an equal chance of capture - no immigration or emigration in time interval between 1st and 2nd sample • In a survey to estimate a monarch butterfly population in Strathclyde Park, the following data were obtained. • Number of monarch butterflies first captured, marked and released = 540 • Number of marked monarch butterflies in second capture = 60 • Number of unmarked monarch butterflies in second capture = 180 • Calculate the estimated population of monarch butterflies in Strathclyde Park. d) Monitoring Populations what you need to know • Presence, absence or abundance of indicator species can give information of environmental qualities, such as presence of pollutant. • Mark and recapture is a method for estimating population size. A sample of the population is captured and marked (M) and released. After an interval of time, a second sample is captured (C). If some of the individuals in this second sample are recaptures (R) then the total population N = (MC)/R, assuming that all individuals have an equal chance of capture and that there is no immigration or emigration. • Methods of marking include banding, tagging, surgical implantation, painting and hair clipping. • The method of marking and subsequent observation must minimise the impact on the study species. • Classification of vegetation types is based on indicator species within the community structure. e) Measuring and recording animal behaviour e) Measuring and recording animal behaviour what you need to know • An ethogram of the behaviours shown by a species in a wild context allows the construction of time budgets. • Measurements such as latency, frequency and duration. • The importance of avoiding anthropomorphism. Measuring and Recording Animal Behaviour • When sampling a populations size, abundance or diversity within an ecosystem, the behaviours of animals may also be recorded. • Ethograms are a catalogue or inventory of behaviours or actions exhibited by an animal. • These are particularly important when dealing with the welfare of animals eg in captivity or while being observed in their territory. • A detailed list with clear defined descriptions can be produced (qualitative vs quantitative!) • e.g. a hamster in a cage Avoiding anthropomorphism • Anthropomorphism is a particular problem when studying animal behaviour. It is important to treat information in a scientific manner and not attribute human characteristics to nonhuman species. • Remaining objective in behaviour studies is helped by using measurable, clearly defined definitions. • Latency – the time between a stimulus and response • Frequency – how often a particular behaviour occurs • Duration – the length of time a particular instance of a behaviour lasts. Time budgets • All of these can be used to produce a clear picture of how a particular species behaves. • The time budget is the time allocated to particular behaviours in a given time frame. • Comparisons of animals in the wild and animals in other contexts e.g. zoos can highlight changes from the normal time budget. e) Measuring and recording animal behaviour what you need to know • An ethogram of the behaviours shown by a species in a wild context allows the construction of time budgets. • Measurements such as latency, frequency and duration. • The importance of avoiding anthropomorphism. Past Paper Questions CfE AH Specimen Paper • Section 1: Q25 • Section 2: Q10 Think, pair, share • In pairs:-think back and answer the following:1. 2. 3. 4. 5. 6. 7. 8. Why do we monitor populations of plants/animals? How do we monitor these populations? Name two ways we can sample plant and animal species. What is the abundance and diversity of an organism. Explain the process of random, systematic and stratified sampling. What do we use to identify organisms? What are dependent, independent and confounding variables? Describe how you completed one of the practicals; including equipment, variables and techniques used.