What is biodiversity A huge variety of different types of plants and animals live on Earth We use the word biodiversity a combination of the words biological and diversity to describe this variety Types of biodiversity There are three types of biodiversity Genetic Animals and plants of the same species can have slightly different genes Species A variety of species live in all the different habitats and ecosystems on Earth Ecosystem There are also many different types of ecosystems on Earth Genetic biodiversity Importance All types of biodiversity genetic species and ecosystem are important Genetic diversity helps keep species healthy and resistant to disease or climate change Species diversity is important for food chains in ecosystems If one species is lost every species will be affected Ecosystem diversity supports millions of different animal and plant species Around 1 9 million species have been recorded on Earth There are probably around 8 9 million in total 4
Humans Humans benefit from biodiversity We rely on plants and animals for food medicine and construction among many other uses Plants also help to maintain oxygen in the atmosphere Some people also believe that we should protect biodiversity because humans have a moral responsibility to look after Earth Ecosystem biodiversity Species biodiversity At risk Extinctions and habitat destruction can happen naturally Throughout Earth’s history there have been five mass extinctions These happened naturally due to volcanic eruptions ice ages and meteor impacts Some scientists believe we are entering a sixth mass extinction caused by humans Humans are the biggest threat to biodiversity today Many types of dinosaurs became extinct during a mass extinction 65 million years ago It was thought to have been caused when a giant meteor hit Earth 5
Genetic diversity All members of a species have mostly the same DNA genetic information However there is also some diversity in DNA which helps species to survive Small differences It’s easy to see small differences in DNA in humans Our physical characteristics such as skin color hair color and risk of developing certain diseases change from person to person However nearly all our DNA around 99 9 percent is the same Animal differences All living things have genetic diversity Just like humans some members of a species may look slightly different or be naturally resistant to a disease These differences can happen randomly or they can be passed down from parent to child Natural selection Genetic diversity helps animals and plants to evolve or change for the better over time This happens through a process called natural selection Some members of a species may randomly have a genetic advantage For example they may not catch a certain disease while others do The ones who do not catch the disease are more likely to survive and reproduce passing on their DNA to the next generation Over time more and more members of the species will be born with the helpful genetic difference 6
Habitat adaptations Species adapt to their habitat through natural selection If a member of a species is born with an advantage such as thick fur in a cold habitat they will be more likely to survive and pass on this advantage Animals continue to evolve as their habitats change In this way some animals will be able to survive changes in their habitat such as global warming GM crops Scientists can change the DNA of certain plants to make them more useful to humans They are called genetically modified GM crops For example the bananas that we eat have been changed so that they don’t have seeds This makes them nicer to eat This wild banana contains many seeds Cloning Some GM crops such as bananas can’t reproduce naturally because they don’t have seeds Instead they are cloned genetically identical copies of each other are made This means that there is no genetic diversity If a new disease attacked bananas none of the bananas would be naturally resistant to it This means that the entire species could die out Inbreeding If there is only a small population of a species there is less genetic diversity This means that any genetic problems are more likely to spread and affect more of the species Having closely related parents can lead to genetic and health problems for plants and animals This is why genetic diversity is important 7
