hi everyone welcome to IGCSE study buddy where you can revise biology topics from the Cambridge IGCSE syllabus if you are enjoying this video so far please don't forget to hit the like button and subscribe to our Channel in this video you are going to learn part 2 of chapter 20 human influences on ecosystems pollution is when harmful substances get into the environment and make things dirty or unsafe for living things human activities have led to the pollution of water land and air let's first talk about water pollution aquatic ecosystems can become polluted with human waste like untreated sewage pesticides and excess fertilizers used in agriculture when fertilizers and sewage enter the marine environment dead zones form where there isn't enough oxygen for life to thrive this is called eutrophication and the process is as follows when untreated sewage and excess fertilizers get into the streams and rivers IT Supplies an excess of nitrates and other ions for microscopic algae which are producers this leads to the excessive growth of producers due to the nutrient overload when these plants and algae die they are decomposed by bacteria due to the increased amount of producers there will also be increased decomposition following their death during decomposition there is increased aerobic respiration and oxygen is used up by the decomposers as a result there will be a reduction in dissolved oxygen therefore organisms that need the dissolved oxygen in water can't survive and will die overall eutrophication caused by human waste inputs can disrupt the balance of aquatic ecosystems by depleting oxygen levels and harming the organisms dependent on it Plastics are non-biodegradable this means that they don't break down naturally over time like other materials instead they persist in the environment for a very long time without fully decomposing non-biodegradable Plastics have harmful effects on aquatic ecosystems and terrestrial or land ecosystems so let's first look at the effects on aquatic ecosystems pollution plastic waste in water disrupts the Natural Balance and harms marine life habitat destruction animals get trapped or eat plastic causing injuries or death and disrupting their homes contamination Plastics release harmful chemicals polluting the water and harming aquatic organisms as Plastics break into tiny pieces they release harmful toxins that hurt sea creatures and these pieces also get into the food that animals eat now let's look at the effects on terrestrial ecosystems soil pollution plastic waste in the soil contaminates the land affecting plants and nutrient Cycles Wildlife impacts animals can be harmed by encountering plastic waste in their habitats spread of microplastics plastics break down into tiny particles that can contaminate soil and affect wildlife this is why it's crucial to reduce plastic waste and practice proper disposal and recycling to minimize these impacts next air pollution methane and carbon dioxide are gases that contribute to the enhanced Greenhouse Effect and climate change methane pollution comes from livestock gases released by animals like cows and sheep landfills trash breaking down without air produces methane carbon dioxide primarily comes from human activities such as burning fossil fuels like oil gas or coal for energy and Industrial processors these gases trap heat in the atmosphere intensifying the greenhouse effect leading to global warming and climate change the effects include altered with the patterns rising sea levels and more frequent and severe extreme weather events impacting ecosystems and human lives conservation means taking care of Natural Resources to make sure they can be properly used now and in the future a sustainable resource is one which is produced as rapidly as it is removed from the environment so that it does not run out some resources can be conserved and managed sustainably for example forests and fish stocks forests can be conserved using education that is telling people why forests are important and how to take care of them for example people may learn the importance of buying products that are sourced sustainably protected areas creating special zones where cutting down trees is limited to keep forests safe quotas deciding on how many trees can be cut so we don't take too many and replanting planting new trees to replace the ones we use so the forest stays healthy fish stocks can be conserved using education teaching people not to catch too many fish and why it's important closed Seasons deciding times when fishing is off limits so fish can grow and make babies quotas figuring out how many fish can be caught so there's always enough left and controlled net types and mesh size using fishing gear that lets small fish escape and catchers only what's needed an endangered species is a type of plant or animal that has very few of its kind left in the world and is at risk of Disappearing forever when a species is extinct it means there are none of them left anywhere in the world they have completely vanished organisms become endangered or extinct because of different reasons climate change that is changing with the patterns and temperatures can make it hard for them to survive habitat destruction when their homes are destroyed they have nowhere to live hunting people hunting them too much can make their numbers go down a lot over harvesting taking too many of them from nature can make their populations shrink pollution harmful stuff in the air water or soil can make them sick or unable to reproduce introduced species new animals or plants coming into their habitat can cause problems like eating their food or spreading diseases here's how endangered species can be conserved monitoring and protecting species and habitats keeping a close watch on endangered species and their homes to make sure they stay safe and healthy education teaching people why these species are important and how to help protect them captive breeding programs taking care of endangered animals in special places helping them have babies and releasing them back into the wild seed banks storing the seeds of endangered plants in a safe place so they can be grown again if they disappear from the wild so the reasons for having conservation programs are maintaining or increasing biodiversity conservation programs help keep many different types of plants and animals alive which is important for Nature's Balance reducing Extinction these programs work to prevent animals and plants from disappearing forever protecting vulnerable ecosystems they help keep delicate environments safe and healthy and maintaining ecosystem functions conservation keeps nature working smoothly like recycling nutrients and providing resources like food drugs Fuel and genes captive breeding programs are vital for saving endangered species they use methods like AI or artificial insemination and in vitro fertilization to help these vulnerable animals reproduce and survive artificial insemination in captive breeding scientists help animals reproduce by collecting sperm from a male and inserting it into a female's body to fertilize her eggs this way animals can have babies without needing to be together in vitro fertilization or IVF in this method eggs are taken from a female and fertilized with sperm outside her body in a lab then the fertilized eggs are put back into the female's body or into a surrogate mother helping endangered animals to have babies even when natural breeding is difficult IVF in captive breeding can also be used to make sure that endangered animals have babies with different genes which helps keep the species healthier and better able to survive finally let's learn the risks to a species if its population size decreases when a species has fewer and fewer individuals its genetic variety decreases this makes them weaker against diseases and changes in the environment which can lead to more of them getting sick or dying this puts them at a higher risk of Extinction that concludes chapter 20 human influences on ecosystems are you enjoying our videos are they helping you here's a way you can show your appreciation and support our continued efforts you may use YouTube super thanks to send us thanks thank you hope this video helped you please share your thoughts and suggestions in the comment section thank you for watching and please don't forget to subscribe to IGCSE study buddy for more biology revision videos bye