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Module 3: Biodiversity and Evolution. Biodiversity and evolution. Evolution has generated a very wide variety of organisms. The fact that all organisms share a common ancestry allows them to be classified. There is increasing recognition of the need to maintain biodiversity. Biodiversity.

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Module 3: Biodiversity and Evolution


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    1. Module 3:Biodiversity and Evolution

    2. Biodiversity and evolution • Evolution has generated a very wide variety of organisms. • The fact that all organisms share a common ancestry allows them to be classified. • There is increasing recognition of the need to maintain biodiversity.

    3. Biodiversity • Biodiversity is an important indicator in the study of habitats.

    4. Classification • Classification is an attempt to impose a hierarchy on the complex and dynamic variety of life on Earth. • Classification systems have changed and will continue to change as our knowledge of the biology of organisms develops.

    5. Evolution • “Nothing in biology makes sense except in the light of evolution” • Theodosius Dobzhansky, 1973.

    6. Maintaining Biodiversity • Maintaining biodiversity is important for many reasons. • Actions to maintain biodiversity must be taken at local, national and global levels.

    7. 2.3.1. Biodiversity Module 3: Biodiversity and Evolution

    8. Learning Outcomes • define the terms ‘species’, ‘habitat’ and ‘biodiversity’ • explain how biodiversity may be considered at different levels; • habitat, • species • genetic

    9. Biodiversity • The biodiversity of an area is a measure of: • Different ecosystems • Number of species • Number of individuals of each species

    10. Biodiversity • “structural and functional variety in the living world” • Levels of biodiversity • Range of habitats in which different species live • The differences between species • Genetic variation between individuals of the same species

    11. Species - definition • Species “a group of organisms, with similar morphological, physiological, biochemical and behavioural features, which can interbreed to produce fertile offspring, and are reproductively isolated from other species” • This often leads to disagreements and uncertainties when classifying or identifying species

    12. Group of organisms Capable of interbreeding Capable of producing fertile offspring Reproductively isolated from other groups “biospecies” Group of organisms showing similarities in characteristics Morphological Physiological biochemical Ecological behavioural Species – the two groups of criteria

    13. Habitat – definition • A habitat is the place where individuals in a species live. • Organisms show adaptations to their habitat • A full description of the habitat includes the physical and biological factors that characterise that environment

    14. Examples of habitats • Name of the place • A description of dominant vegetation • Coniferous forest • Oak woodland • Tropical rainforest • Grassland • A type of environment • Freshwater pond • Rock pool on a rocky shore

    15. The State of the planet • David Attenborough presents a series of three programmes looking at the “state of the planet” to address the concern below. • One species (humans) can so alter its environment that it can destroy whole species, and indeed whole environments. • How great is the damaged that is being caused? • Why is it that what we do is so destructive? • What can we do to change?

    16. The state of the planetProgramme No. 1 • The Biodiversity on Earth • In order to understand the impact that humans are having on the environment we first need to understand the variety of life on the planet, the biodiversity. • Why conserve ecosystems?

    17. Measuring Biodiversity

    18. explain the importance of sampling in measuring the biodiversity of a habitat describe how random samples can be taken when measuring biodiversity Measuring Biodiversitylearning Outcomes

    19. Measuring biodiversity • To measure biodiversity you need to find out • What species are present • The abundance of each species • The distribution of each species across the area • Compile a species list • Identification keys • Observation • Trapping of mobile animals

    20. Measuring biodiversity • Distribution • Where the species is found • Abundance • How many of each species are present • Estimating abundance • Take a representative sample • Multiply up

    21. Random sampling • Study a small part of the habitat • Sample sites must be selected at random • Take samples at regular intervals • Use random number tables • Select co-ordinates from a map

    22. Number of samples • The number of samples taken will depend on • The size of the habitat • The time of year • The diversity of the habitat being studied

    23. Recording results • Prepare a table • Space for all species • Space to record the data for each sample site

    24. Sampling techniques • Quadrats • Choose a suitable quadrat size • Place quadrat at random • Identify plants • Measure their abundance • Transects • Put a tape measure across the habitat • Record all species touching the line • Can record at intervals

    25. Belt transect Interrupted belt transect Continuous belt transect Used to survey rocky shores or sand dunes Interrupted belt transect continuous belt transect Sampling techniques

    26. Percentage Cover Proportion of quadrat’s area occupied by the species Grids can help with estimates Use a point frame within a quadrat Include bare ground Abundance scale – subjective ACFOR scales Abundant Common Frequent Occasional Rare Species frequency Proportion of quadrats with the species present Measuring abundance

    27. Sampling in School Grounds • Suggested activities • Transect in grass outside chapel • Random quadrat sampling of two sites • Optimum quadrat size for pinkie fields • Optimum quadrat number • Species frequency on pinkie fields • Comparison of percentage cover and ACFOR • All students quantify the same 10 quadrats and allow for comparison

    28. If the animals are mobile Observation Observation of signs left behind Owl pellets, droppings, burrows etc Catch or trap animals and estimate numbers from the trapped sample Catching animals Sweep netting Kick sampling Tree sampling Pitfall trap Tulgren funnel Light trap Sampling Animals

    29. Surveying school grounds • Suitable methods that could be used in school include • Sweep netting in the long grass • Tree sampling • Pitfall trap • Tulgren funnel • To allow for a comparison, each sample should be done at two sites, and some abiotic readings should be taken.

    30. Summary of the impact of sampling • Sampling may cause damage to a habitat • Temporary disturbance • Long term disturbance • Example • Trampling • Digging for pitfall traps etc

    31. Why do we need to study habitats? • Assess human impact • EIA – Planning process • To highlight the importance of maintaining habitats and reducing the damage

    32. Learning Outcomes • describe how to measure species richness and species evenness in a habitat • Use Simpson's Index of diversity (D) to calculate the biodiversity of a habitat using the formula D = 1 – (∑(n/N)2) • Outline the significance of both high and low values of Simpson’s Index of Diversity (D)

    33. Measuring Biodiversity • Species richness • Number of species present in the study area • Species evenness • Measure the abundance of individuals in each species • Increasing species richness and species evenness will increase biodiversity

    34. Simpson’s diversity Index • Measure of biodiversity taking into account species richness and species evenness • Formula • D = 1 – [∑(n/N)2] • n = number of individuals of a particular species • N = total number of all individuals of all species

    35. Progress Question • Use Simpson’s index to calculate the diversity of a habitat that contains the following organisms • 20 woodlice • 5 mice • 1 shrew • 32 earthworms • 15 grasshoppers • 1 owl • Comment on the diversity of this habitat

    36. Calculating simpson’s

    37. Answers to progress questions • D = 1 – 0.306 • D = 0.694

    38. 2.3.2 Classification Module 3: Biodiversity and evolution

    39. Classification • Classification is an attempt to impose a hierarchy on the complex and dynamic variety of life on Earth. • Classification systems have changed and will continue to change as our knowledge of the biology of organisms develops.

    40. Learning Outcomes • Define the terms classification, phylogeny and taxonomy. • Explain the relationship between classification and phylogeny. • Describe the classification of species into the taxonomic hierarchy of domain, kingdom, phylum, class, order, family, genus and species.

    41. Definitions • Classification • The grouping of organisms into categories based on various features • Phylogeny • Study of evolutionary relationships between organisms • Taxonomy • The study of the principles of classification • Taxon • Classificatory group

    42. Natural Classification • Concept of the species • Capable of breeding to produce fertile offspring • Have common ancestry • Have very similar genes • Hierarchy of classification • Closely related species are placed together in groups • Closely related groups are placed together in a larger group • Modern classification reflects the evolutionary distance between species

    43. Evolutionary tree • Any two species alive today will share a common ancestor from the past • The time when the two species started to evolve separately is a branch point on the tree

    44. Progress Questions • What is meant by the term classification? • What is meant by the term phylogeny? • What is the relationship between natural classification and phylogeny?

    45. Answers to progress questions • What is meant by the term classification? • Classification is the sorting of living things into groups • Natural classification does this by grouping things by how closely related they are • What is meant by the term phylogeny? • The study of evolutionary relationships between organisms • What is the relationship between natural classification and phylogeny? • Natural classification groups things according to how closely related they are • This should match the evolutionary tree produced by considering how recently organisms shared a common ancestor.

    46. Classifying living things • Carl Linnaeus – 18th Century • Devised a scheme of classification • Organisms were put into a series of ranked categories • Categories are taxonomic groups (TAXON) • 5 kingdom classification

    47. Hierarchy of classification • Domain • Kingdom • Phylum • Class • Order • Family • Genus • Species • This is the basic unit of classification

    48. Hierarchy of classification

    49. Examples of Classification