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What was the principle behind Darwin's theory of evolution? Explain Lamarck’s theory of evolution. What sort of time period does evolution normally happen over? What can cause it to happen more quickly when there is a change in the environment? Give three reasons why Darwin's theory of evolution was only gradually accepted: Outline the key principles of natural selection, Use the evolutionary tree diagram on the right to answer the following questions: Which group of organisms are most closely related to Birds? Fill in the gaps in the table below. Are fish or mammals more closely related to dinosaurs? Explain how a mutant gene that allows a group of people who live in the Philippines to develop gills could result in all humans being able to breathe under water in 100 years time. Fish Body covering Where it lives Reptiles Birds Mammals Moist skin Lays eggs with leathery shell How offspring are produced How it breathes Warm or cold blooded Amphibians Lungs cold cold Land Land What was the principle behind Darwin's theory of evolution? All species evolved from simpler life forms that first developed more than 3 billion years ago Give three reasons why Darwin's theory of evolution was only gradually accepted: •Challenged religion – idea that god made all living organisms •Insufficient evidence at time •Mechanism of inheritance not discovered until 50 years later Outline the key principles of natural selection, • Organisms within a species show variation due to mutation causing differences in their genes • Some of these genes will give characteristics that increase changes of survival • These organisms are then more likely to breed and pass these genes on Use the evolutionary tree diagram on the right to answer the following questions: Which group of organisms are most closely related to Birds? Dinosaurs Fill in the gaps in the table below. Are fish or mammals more closely related to dinosaurs? Mammals Explain how a mutant gene that allows a group of people who live in the Philippines to develop gills could result in all humans being able to breathe under water in 100 years time. •Global warming causes flooding so less land •Mutant gene = can live in water so more like to survive •More likely to pass genes on •Offspring more likely to survive •Eventually everyone has gills Explain Lamarck’s theory of evolution. • Variation between organisms within a species is due to changes acquired during their lifetime • These acquired characteristics (not genes) are passed on. What sort of time period does evolution normally happen over? Millions of years What can cause it to happen more quickly when there is a change in the environment? Advantageous mutation Fish Amphibians Reptiles Birds Mammals Body covering Scales Moist skin Scales Feathers Fur How offspring are produced Lays soft eggs Lays eggs in jelly Lays eggs with leathery shell Lays eggs with hard shells Gives birth to live young Gills Lungs, gills, skin Lungs Lungs Lungs cold cold cold warm Warm Water Lives part of its life in water Land Land Land How it breathes Warm or cold blooded Where it lives