Learn the key concepts in ecology and what makes populations change over time, with Professor Lindsay Turnbull from the University of Oxford Ecology is the study of plants and animals in their environments but what kinds of questions do ecologists try to answer? We begin with a population - a group of organisms belonging to the same species that live in one place. Some populations are stable, while others boom and bust, and we find out why births and deaths are key to understanding stability. We then consider why there are so many species on Earth and in doing so discover the ecological niche that constrains organisms to a specific role. Finally, we take a quick look at humans, who have broken out of their niche and taken control of the planet. Erratum - Mammal biomass on Earth The figures given in the video are incorrect. The actual figures are: 34% humans, 62% livestock and 4% wild mammals. https://ourworldindata.org/wild-mammals-birds-biomass Timestamps: 00:00 Intro 00:20 Titles 00:29 Key ecological questions 01:18 The state of populations: births and deaths 02:58 The rabbit versus the albatross 04:32 Keystone species: the case of the sea otter 06:20 Competition: the ecological niche 08:23 Humans – the ultimate competitor? 11:26 Outro