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National 4 Biology Key Area 5: Adaptations for survival National 5 Biology Key Area 4: Adaptation, natural selection and the evolution of species Quick Question 1. Name one biotic factor that can affect biodiversity. Food Availability or Predation or Grazing or Disease or competition 2. Name the piece of sampling equipment used to measure light intensity Use a light meter 3. Describe one precaution to be taken when using this piece of equipment All group members should stand well clear of the meter to prevent shadows National 5 outcomes By the end of the lesson you will be able to ….. • Define the word Mutation. • Give examples of different mutations • Give examples of mutagenic agents Do you know what this is? Malignant Melanoma (Skin cancer) Not all mutations are inherited. Exposure to certain factors (e.g. UV light in sunlight) can cause spontaneous mutations that lead to cancer. Factors that can lead to mutations • We now know that exposure to most radiation (UV, gamma and even X-rays) can be carcinogenic. • X-ray technicians will either leave the room during an Xray or wear a lead lined vest Mutations A mutation is a random and spontaneous change to genetic material (DNA). A mutagenic agent is a factor that can increase the rate of mutations E.g. • Radiation (X-rays), • High temperatures • some chemicals (e.g. mustard gas). Quick Question 1. Describe what is meant by a mutation. A mutation is a random and spontaneous change to genetic material (DNA). 2. Match up the mutagenic and its possible effect on living tissue: A. UV radiation 1. Lung Cancer B. Chemicals in cigarette smoke 2. Mouth Cancer C. Mustard Gas 3. Skin Cancer Some mutations are ‘neutral’ • Evidence of the mutations may be visible • Makes no difference to the overall health of the organism Mutations can be…. Advantageous: e.g. bacterial resistance to antibiotics. Neutral: e.g. Free Ear lobes or attached ear lobes. Disadvantageous: Malignant Melanoma (skin cancer) Why are mutations important? • Mutations are the only source of brand NEW GENES (alleles) in a population. • Mutations are important because they increase variation within a species. • This allows species to adapt to be better suited their environment. Mutations – The Science of Survival (45 minutes) (Up to 21 minutes) Can you now …. • Define the word Mutation. • Give examples of different mutations • Give examples of mutagenic agents Quick Question 1. Give two examples of mutagenic agents. UV light or X rays or the chemicals in cigarette smoke 2. Match up the mutation and its effect on survival: A. Advantage 1. Widow’s peak hairline B. Disadvantage 2. Cystic Fibrosis C. Neutral 3. Antibiotic Resistance in Bacteria National 4 outcomes By the end of the lesson you will be able to ….. • Define the word ‘adaptations’ • Give examples of behavioural, physiological and structural adaptations Variation in a species • All populations show variation in appearance and in genetics. What type of variation is show in the beetle population? • Variation in a population is caused by a random spontaneous mutation • It may or may not give that organism an advantage Adaptations in Action! Watch this clip and write down any adaptations that you see…. BBC Hunting & Escaping : Camouflage (6:39) Amazing Animal Adaptations and Evolutionary Problem Solving (1 hour) Adaptations • An adaptation is an inherited characteristic that makes an organism well suited to its environment. • This increases their chances of survival and being able to reproduce. • Adaptations can be: – structural – physiological – behavioural Predator, e.g. a lionGood eyesight for hunting prey Strong jaws and sharp teeth for ripping flesh Sharp claws for gripping prey Hunting Lesson - Wildlife Specials: Lions - Spy in the Den - BBC Prey, e.g. rabbit Ability to move quickly Good hearing for detecting predators Bat Uses sound to detect prey Skin between its fingers to form a wing Bats hunting their prey - Top Bat - BBC Eagle Strong and hooked beak to kill and tear flesh off of their prey Large talons to grip onto prey Pelican Large ‘pouch-like’ beak for scooping up fish from the water Webbed feet for swimming Finding Nemo Pelicans & Seagulls Scene Quick Question 1. Which bird would eat the rabbit and why? Can you now …. • Define the word adaptations • Give examples of behavioural, physiological and structural adaptations Key Area Assessment • You are now ready for your next National 4 Key Area Assessment • This will be one question on Key Area 5 “Adaptations for survival” • This will be done during your next lesson Quick Question 1. What food are the animals adapted to eat and why? Lion Fish Pelican Seeds Finch Meat National 5 outcomes By the end of the lesson you will be able to ….. • Describe how animals become adapted to their niche • Give an example of animal that has done this Natural Selection Charles Darwin (1809 – 1882) Theologist and self-taught naturalist. Believed living things evolved. Suggested evolution happed by natural selection or “survival of the fittest”. Gathered detailed evidence from voyages (e.g. The Galapagos Islands) to support his theory. Darwin did not provide an explanation of how features were passed on. Darwin explored the Galapagos Islands from April through October 1835. Inspired by the nature of the island chain When and where he started thinking about what was to become his theory of evolution by natural selection. Animals live there that are found nowhere else on earth. This makes them endemic 30 Endemics Unique adaptations of Galapagos endemics inspired Darwin – 13 species of finches – 1 penguin species – 1 giant tortoise species – 1 marine iguana species – 7 species of lava lizard – 14 species of sea cucumber – 1 species of sea lion – 1 species of hawk – several species each of mockingbirds, doves, owls, flycatchers, and yellow warblers 31 Darwin’s Finches •Darwin was most inspired by the birds in the islands •He observed that finches had adapted to have different types of beak. •He proposed that they all evolved from a common ancestor Darwin’s Finches • Darwin proposed that the Finches had all evolved from a common ancestor but had developed a different shape and size of beak. • This allows the finches to eat different types of food. This reduces competition. • This gave them a “selective advantage”. 1. 2. 3. 4. 5. Different beaks for different niches Copy the table below Using chopsticks, transfer as many of the grains of the rice into a plastic beaker as you can in 60 seconds Calculate the total number of grains transferred by your group Enter the number in the table in you jotter Repeat 2-4 using a teaspoon and then a spatula Chopsticks Beak Group 1 Group 2 Group 3 Group 4 Total Average Teaspoon Beak Tweezers Beak Different beaks for different niches 1. Which “beaks” were best and least adapted for picking up the grains of rice? Best – teaspoon, Least - chopstick 2. Which group had an advantage over the others? Teaspoon beaks 3. How could results have been more reliable? Repeat for Reliable Results 4. As an 18 year old, you transfer populations of each type of finch to an island where the only food source is rice. You return to the island as a 98 year old. Using the term “natural selection”, predict the numbers of each type of finch on your return to the island. Teaspoon – high, tweezers – moderate, chopsticks – extinct. Quick Question 1. Decide if each statement is true or false. If it is false then correct the underlined word. Statement T or F Correction A mutation is a random and spontaneous change to protein. F Genetic material OR DNA Adaptations can be structural, physiological or behavioural. Darwin’s Finches evolved different shapes and sizes of beaks to increase competition T F Decrease OR reduce National 4&5 outcomes By the end of the lesson you will be able to ….. • Explain what the phrase “survival of the fittest” means. • Describe the process of natural selection Survival of the Fittest •Darwin proposed that organisms better adapted to their environment survive. •He called this ‘survival of the fittest’ Natural Selection Is a process in which individuals that are better adapted to their environment survive and breed, whilst those less well adapted die before reproducing. Charles Darwin (1809 – 1882) Theologist and self-taught naturalist. Believed living things evolved. Suggested evolution happed by natural selection or “survival of the fittest”. Gathered detailed evidence from voyages (e.g. The Galapagos Islands) to support his theory. Darwin did not provide an explanation of how features were passed on. genotype Word Selective pressure phenotype Selective advantage Meaning The type of genes an organism has, e.g. a gene for blue eyes. The physical appearance of an organism. An aspect of the environment that selects one characteristic over another, e.g. climate, predators or disease. The characteristic of an organism that enables it to survive and reproduce better than other organisms in a population in a given environment Natural Selection Sexual reproduction results in more offspring than environment can support Offspring show inherited variation. They have different genotypes and phenotypes. Struggle for Survival: Exposure to different selection pressures Some rabbits die of disease Struggle for Survival: Exposure to different selection pressures Some rabbits with thinner coats die of exposure Some rabbits die of starvation Some slower rabbits are caught by Those rabbits poorly adapted to their environment die before predators reproducing. Rabbits with the selective advantage (best adapted to their environment) survive and reproduce. The alleles (genes) that give the selective advantage are passed on. Eventually, the species changes over time. Quick Question 1. Darwin used the term “survival of the fittest”. Explain what this means. Organisms better adapted to their environment survive! 2. Pet shops sell white and brown rabbits. White rabbits are easily seen by foxes. Use Darwin’s theory of evolution to explain why white rabbits are rare in the wild. White rabbits easily seen and eaten by foxes Die before reproducing Brown rabbits are best adapted to avoid predation – have selective advantage Brown rabbits survive and reproduce, passing on genes to give selective advantage National 5 outcomes By the end of the lesson you will be able to ….. • Give an example of ‘high speed’ natural selection Natural Selection in Action • He was wrong! • Two ‘modern’ day, high speed examples are: – The evolution of antibiotic resistance bacteria – The Peppered moth Natural selection occurs far too slowly to be witnessed in a man’s lifetime. The Story of The Peppered Moth Once upon a time in pre-industrial England…… Birch tree with pale bark Moths with light wings were camouflaged on trees Can you spot the pale moth???? Moths with dark wings were easy to spot by predators What would you expect to happen to the ratio of each type? Along came the industrial revolution – and lots of pollution Tree trunks were discoloured by pollution Can you spot the dark moth???? Now the black moths had the selective advantage What would you expect to happen to the ratio of each type? As coal burning stopped the trees returned to their natural colour Moths with light wings were camouflaged on trees again Paragraph 1…. • Before the industrial revolution in Britain, most peppered moths were pale. • Pale moths were well camouflaged against the pale trees that they rest on. • Moths with a mutant dark colouring were easily spotted and eaten by birds. • This meant the pale moths were better adapted to their environment, giving them the selective advantage over the darker variety. • Therefore the pale variety survived to reproduce and their numbers increased. Paragraph 2…. • Pollution in industrial areas blackened the birch trees with soot. • This meant that the mutant dark moths were now camouflaged, while the pale variety became more vulnerable to predators. • This meant the dark moths were now better adapted to their environment, giving them the selective advantage over the paler variety. • Therefore the dark variety survived to reproduce and their numbers increased. Quick Question 1. Use these 6 bullet points to write a brief paragraph about Natural Selection – variation exists – struggle for survival – best adapted organisms survive – reproduce – inherited characteristics are passed on – species change over time • Variation exists in natural populations. All organisms struggle for survival. The best adapted organisms survive and reproduce. This means their inherited characteristics are passed on. As this process is repeated the species change over time to become as well adapted to their environment as they can be. Quick Question 1. Decide if each statement is true or false. If it is false then correct the underlined word. Statement T or F Correction Evolution a process in which individuals that are better adapted to their environment survive and breed F Natural Selection A characteristic of an organism that enables it to survive and reproduce better than other organisms is a selection pressure. F Selective advantage A species is a group of interbreeding organisms whose offspring are fertile. T National 5 outcomes By the end of the lesson you will be able to ….. • Define the word species • Describe the process of speciation Species Think back to biodiversity! • 8.7 million named species at last count (2011) • Estimates between 13 - 100 million in total • A group of interbreeding organisms whose offspring are fertile Different Species STERILE OFFSPRING X ZEBRORSE Young that are unable to produce more of their own kind on reaching maturity • Some species are closely related meaning that they can interbreed. Species • 8.7 million named species at last count (2011) • Estimates between 13 - 100 million in total • A group of interbreeding organisms whose offspring are fertile Where have all these species come from????? National 5 outcomes By the end of the lesson you will be able to ….. • Define the word species • Describe the process of speciation Speciation • A species is “a group of interbreeding organisms whose offspring are fertile” • Speciation is the process by which a new species is formed. Speciation – Step by Step 1. 1. A large population of interbreeding organisms of the same species live together in the same habitat. 1. 2. The population is divided into 2 smaller groups by an isolation barrier. 2. The sea acted as a geographical barrier for the endemics on the Galapagos Islands. 72 Geographical Barrier Geographic isolation occurs when two populations are separated by geographic barriers such as rivers, mountains or the grand canyon. Kaibab Abert Copyright Pearson Prentice Hall Ecological barrier • Ecological barriers cause a change in the environment. • This change is caused by an abiotic factor, e.g. temperature, O2 concentration and pH. E.g. fish living in different positions in the water column. Reproductive Barriers Reproductive barriers may occur when: • two or more species reproduce at different times. Reproductive Barriers Reproductive barriers may occur when: • Changes in courtship behaviours make them ‘unattractive’ to the opposite Copyright Pearson Prentice Hall This can be: Geographical rivers, mountains, sea. Ecological extreme changes in temperature, pH or humidity. Reproductive a lack of attraction between the populations 1. 2. 2. The population is divided into 2 smaller groups by an isolation barrier. Speciation – Step by Step 3. 3. Different random and spontaneous genetic mutations take place in each population. This may or may not give the organism a selective advantage. Speciation – Step by Step 4. 4. Different conditions exist on either side of the barrier. This creates different selection pressures on each population. Individuals with a selective advantage survive and reproduce. Speciation – Step by Step 5. 5. Following more natural selection the two populations become genetically different to each other. The isolation barrier is removed. Population A cannot produce fertile young with population B. A new species has been formed. • Look at how ONE species change changes over time! Great Speciation Video • http://www.youtube.com/watch?v=Q2vs G77PZ80