3 Topics you need to know: Species and adaptationsExtinctionEnergy Transfer in food chains/websThe Carbon CycleThe Nitrogen CycleIndicators of environmental changeLife on Earth and when it originatedVariation and EvolutionNatural SelectionEvidence for EvolutionBiodiversitySustainabilityLets go through each of these topics in more detail!
4 Species and Adaptations Can you answer the following:What is the definition of a species? (1 mark)What is an adaptation? (1 mark)How is a cactus adapted to survive in hot and dry climates? (3 marks)List 4 things animals/plants can compete for? (4 marks)What does a food web show? (2 marks)What is interdependence? (1 mark)
5 ExtinctionA species can become extinct if it is unable to adapt to a change in the environment, what could these changes be? (think of 4)
6 Energy transfer in food chains Almost all organisms are dependent on energy from the sun.Plants absorb a small percentage of the energy from the sun to produce their own food via photosynthesis – the energy is then stored in the plant tissue.Other organisms get energy from eating the plants and almost EVERY food chain starts with a plant.Not all of the energy is passed on to the next organism in food chain, list 3 ways that this energy can be lost? (3 marks)Why is their rarely a 4th level in a food chain?Remember:Percentage efficiency = energy in tissuesEnergy in food eaten x 100
7 The carbon cycleCarbon is a key element in all living things and is continually recycled as follows:Carbon enters the cycle as carbon dioxide from the airPlants fix the carbon into their tissues by photosynthesis and these plants are eaten by animals or die and decomposeCarbon is returned to the air by respiration from plants and animals, decomposition by MO’s and by combustion of organic materials (fossil fuels)
8 Describe what is happening at points A-F The Nitrogen CycleNitrogen is essential to all living things.Nitrogen in airABEProteins in plantsProteins in animalsDFCNitrates in soilDescribe what is happening at points A-F
9 Indicators of environmental change Non living and living indicators existScientists monitor change locally and globallyLiving indicators provide accurate information about levels of pollution and environment changes e.g. Mayfly larvae need high levels of oxygen in water so if they are present suggest that there is little pollutionNon – LivingLivingLevels of Carbon DioxideTemperatureNitrate levels in soilPhytoplanktonLichens (fungus and alga living together)Mayfly larvae
10 Life of EarthLife on earth began 3500 million yrs ago and the 1st life forms were very simpleOver many yrs these have formed the variety of organisms today via evolutionThe changes to organisms over time is due to variation caused by their environment and their genesWhat are the 2 pieces of evidence for evolution and which is more reliable?Why are there some gaps in the records?
11 Variation and Evolution What causes variation in species?What is a mutation?Are all mutations harmful?Evolution involves the development of new speciesIn a population of organisms the genes in the population will change due to mutations, this is known as the GENE POOL
12 Natural SelectionThis is the mechanism that Charles Darwin used to describe how evolution happens.How evolution happens (Copy and complete)Variation exists between members of the same species. This is caused by their _______ , _______ and _______. Some individuals are born with characteristics that help them _________. These individuals will be more likely to _____ and pass on the ________ __________ to the next generation. This is an example of ______ __________Natural Selection environment survive breedsurvival feature mutations genes
13 How quickly does evolution happen? Over a long period of time advantageous genes become the norm in a population.There are examples of natural selection happening much faster:Bacteria becoming resistant to antibioticsHead lice becoming immune to medicationQuestion:What would happen to a group of the same species if they became isolated from each other on separate islands, would they be able to reproduce after many years apart? (3 marks)
14 Charles Darwin Vs Lamarck Task:List the similarities and differences between their theories!Believed that species had an ‘inner urge’ to change and so acquired new characteristics during their lifetime that were passed to offspringBelieved that species evolved over time via natural selection
15 Biodiversity This is the variety of life on Earth including: The number of speciesThe range of different types of plant/animal/microorganismThe genetic diversity (Variation)The rainforest is very biodiverse and could be valuable for finding new medicinesQuestion:Species are becoming exist more rapidly than would be expected, what could be causing this? (4 marks)
16 SustainabilityThis is meeting the needs of people today without harming the resources for future generationsBIODIVERSITY must be maintained to ensure sustainability!Why is a monoculture not sustainable?What can manufacturers do to make products as sustainable as possible?