CCEA A Level Biology
CCEA A Level Biology 5.8 Kingdom Animalia Exam Questions
Free CCEA A Level Biology revision for 5.8 Kingdom Animalia: what you need to know, common mistakes and exam-style questions with answers. Covers evolutionary trends in animals, Cnidaria, Platyhelminthes, Annelida, Arthropoda and Chordata, symmetry, body layers, coelom, segmentation, gut and skeletons.
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About CCEA A Level Biology 5.8 Kingdom Animalia
Section 5.8 of Unit A2 2 is the animal counterpart of Kingdom Plantae. You need to describe five phyla, Cnidaria (for example hydra and jellyfish), Platyhelminthes (planarian and liver fluke), Annelida (earthworm and lugworm), Arthropoda (insects and spiders) and Chordata, and explain the evolutionary trends in body plan they show. Key features are symmetry, the number of body layers, the presence of a coelom, segmentation, the gut (one opening or two) and the type of skeleton or support. Questions often give a photograph or diagram and ask you to assign it to a phylum, or ask you to explain how a hydrostatic skeleton or exoskeleton works.
What you need to know
- Cnidaria Radially symmetrical, diploblastic (two body layers), with a gut cavity (enteron) with one opening. Supported by surrounding water and a hydrostatic skeleton formed by fluid in the enteron.
- Platyhelminthes Bilaterally symmetrical and flattened dorso-ventrally, triploblastic but with no coelom. Gut has a single opening; no specialised skeleton, supported by body tissue. Flat shape gives a short diffusion distance.
- Annelida Bilaterally symmetrical with a true coelom and metameric segmentation. Gut has a mouth and anus. Fluid in the coelom acts as a hydrostatic skeleton, with circular and longitudinal muscles; chaetae give grip.
- Arthropoda Bilaterally symmetrical and segmented, with a hard, jointed exoskeleton of chitin and jointed limbs. The coelom is reduced and the main body cavity is a haemocoel. The gut is complete and specialised.
- Chordata Bilaterally symmetrical with a well-developed coelom, a complete gut and an internal skeleton of bone or cartilage. Segmentation is mainly seen in muscle blocks.
- Trends From Cnidaria to Chordata there is a move from radial to bilateral symmetry, from two to three body layers, appearance of a coelom and segmentation, a gut with two openings, and a change from hydrostatic skeleton to exoskeleton to endoskeleton.
Common mistakes in 5.8 Kingdom Animalia
- Saying flatworms have a coelom. Platyhelminthes are acoelomate.
- Saying cnidarians have a mouth and an anus. They have one opening to the enteron.
- Saying an earthworm's hydrostatic skeleton is just water. It is coelomic fluid in segments, acted on by antagonistic circular and longitudinal muscles.
- Calling the arthropod exoskeleton bone. It is made of chitin.
- Putting jellyfish in a bilaterally symmetrical group. Cnidaria are radially symmetrical.
Try three 5.8 Kingdom Animalia exam-style questions
1. Explain how the hydrostatic skeleton of an earthworm allows movement. (3 marks)
Show the mark scheme answer
Coelomic fluid is incompressible and enclosed in segments; contraction of circular muscles makes a segment long and thin while longitudinal muscles make it short and fat; chaetae anchor segments so waves of contraction move the worm forward.
2. Give two features that distinguish Annelida from Platyhelminthes. (2 marks)
Show the mark scheme answer
Annelids have a coelom; annelids are segmented; annelids have a gut with mouth and anus; annelids are not dorso-ventrally flattened (any two).
3. Suggest why flatworms do not need a specialised gas exchange system. (2 marks)
Show the mark scheme answer
Flattened body gives a large surface area to volume ratio; short diffusion distance to all cells.
5.8 Kingdom Animalia FAQs
What does CCEA A Level Biology 5.8 Kingdom Animalia cover?
It covers the features of Cnidaria, Platyhelminthes, Annelida, Arthropoda and Chordata and the evolutionary trends in symmetry, body layers, coelom, segmentation, gut and skeleton.
Which unit is 5.8 Kingdom Animalia examined in?
It is examined in Unit A2 2: Biochemistry, Genetics and Evolutionary Trends, a 2 hour 15 minute written paper of structured questions and an essay. Related practical skills can also be tested in Unit A2 3.
How should I learn the five phyla?
Build a table with one row per phylum and columns for examples, symmetry, body layers, coelom, segmentation, gut and support, then test yourself using photographs.
