Syllabus Edition

First teaching 2023

First exams 2025

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Locomotion in Organisms (HL) (HL IB Biology)

Revision Note

Cara Head

Author

Cara Head

Expertise

Biology

Reasons for Locomotion

  • Locomotion is the movement or the ability to move from one place to another
  • Locomotion is important to a range of organisms for a variety of reasons
  • This trait is particularly important in the Animal kingdom

Example of Reasons for Locomotion Table

Locomotion reason Animal Example
Foraging for food Guinea pigs These spend at least 70 percent of their time awake searching and eating plants
Escaping from danger Salticidae spiders Jumping spiders use their legs to jump out of the way of potential predators or other dangers
Searching for a mate Salmon Spawning of salmon involves male and female salmon swimming from the ocean to freshwater rivers to mate
Migration Caribou dear Caribou can travel over 3,000 miles a year between their Southern winter ranges and their Northern calving grounds

Adaptations for Swimming

  • Aquatic animals are adapted for a specific movement called swimming
  • Marine mammals in particular have many adaptations that make them excellent swimmers
    • Marine mammals might include dolphins or whales
  • These mammals have all evolved from ancestral land animals that mean they are now capable of surviving underwater  
    • Streamlining of their bodies allows marine mammals to move with ease through relatively viscous water with ease and great speeds
    • Front limbs have been adapted to form flippers which are used mainly for steering; rear legs have been lost altogether to help with streamlining
    • Tails have adapted to form a fluke which is capable of up and down movement and are used for propulsion of the marine mammal
    • Changes to airways by the evolution of a blowhole allows periodic breathing between dives; blowholes can be sealed between dives so that water does not enter the airways

Adaptations of marine mammals diagram

adaptations-for-swimming-in-marine-mammals

Marine mammals have evolved many adaptions from the previous land mammals they once were

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Cara Head

Author: Cara Head

Cara graduated from the University of Exeter in 2005 with a degree in Biological Sciences. She has fifteen years of experience teaching the Sciences at KS3 to KS5, and Psychology at A-Level. Cara has taught in a range of secondary schools across the South West of England before joining the team at SME. Cara is passionate about Biology and creating resources that bring the subject alive and deepen students' understanding