A-Level Biology - Random Sampling - Techniques | Estimating Population Size (2026/27 Exams)

⭐️ Check out our website https://www.cognito.org/ ⭐️ *** WHAT'S COVERED *** 1. The purpose and process of random sampling * Why it is impractical to count every individual in a population * How to use grids and random coordinates to avoid sampling bias * The importance of collecting multiple samples to ensure data is reliable 2. Different sampling techniques and equipment * Using frame quadrats and point quadrats for sessile organisms * Methods for collecting motile organisms including pooters, sweep nets, pitfall traps, tree beating, and kick sampling 3. Methods for estimating population size * Calculating percentage cover for plants like grass * Determining species frequency across multiple quadrats * Calculating species density to estimate the number of individuals per unit area *** EXAM BOARD SPECIFIC INFO *** AQA - You don't need to know all the techniques for sampling animals, or about how to calculate species density OCR - Everything is relevant to your course! CIE - You don't need to know all the random sampling techniques, just pooters and frame quadrats *** CHAPTERS *** 0:00 What is random sampling? 1:51 Different sampling techniques 2:00 Frame and point quadrats 2:25 Sampling motile organisms 3:16 Calculating percentage cover 3:51 Calculating species frequency 4:14 Calculating species density *** PLAYLISTS *** https://youtube.com/playlist?list=PLidqqIGKox7VzYfPIVt8T09xOLNcolCe4&si=8JmDajxjtba6rdc3 https://youtube.com/playlist?list=PLidqqIGKox7UZ3mWhbHv2aA_1vnbsfRPq&si=q3hEKdA4v7kbfwMe https://youtube.com/playlist?list=PLidqqIGKox7UTimdJ3eFcnt6xL9GUt2a6 https://youtube.com/playlist?list=PLidqqIGKox7XPh1QacLRiKto_UlnRIEVh&si=orIUwL3o2jOoiYjT https://youtube.com/playlist?list=PLidqqIGKox7X5UFT-expKIuR-i-BN3Q1g&si=DcihOwUkd9oWbbdp https://youtube.com/playlist?list=PLidqqIGKox7WeOKVGHxcd69kKqtwrKl8W&si=Y8MsO-FK948jnxpS https://youtube.com/playlist?list=PLidqqIGKox7UVC-8WC9djoeBzwxPeXph7&si=-7i5Iq7yOeJrhtu6 https://youtube.com/playlist?list=PLidqqIGKox7VKJD2WxRhoKaI6JGLVean8&si=NH_Q1ujhVgACM2FU #alevel #Biology #study #revision #school #exam #AQA #OCR #Edexcel