Kingdom Animalia 1
What is the main characteristic that makes animals different from plants?
Animals are heterotrophic (they cannot make their own food)
Which level of organization includes cells, tissues, organs, and organ systems?
Organ-system level of organization
What type of symmetry do most animals have?
Bilateral symmetry
Which germ layer forms muscles and most organs
Mesoderm
What is the difference between vertebrates and invertebrates?
Vertebrates have a backbone; invertebrates do not
Which phylum includes animals with pores all over their body?
Porifera (sponges)
What type of digestion do cnidarians have?
Incomplete digestion (one opening)
What is the body symmetry of cnidarians?
Radial symmetry
Which animals have stinging cells called cnidocytes?
Cnidarians
What is the main function of the skeleton in animals?
Support and protection
What type of body cavity do flatworms (Platyhelminthes) have?
They are acoelomates (no body cavity)
What is cephalization?
Concentration of sensory organs and nerves at the head
Which phylum shows the first appearance of bilateral symmetry?
Platyhelminthes
What is the function of flame cells in flatworms?
Excretion and osmoregulation
What is the difference between radial and bilateral symmetry in movement?
Bilateral allows directional movement; radial does not
What type of body cavity do roundworms (Nematoda) have?
Pseudocoelom
How do nematodes reproduce?
Sexually (most have separate sexes)
What is segmentation in animals?
Body divided into repeated sections
Which phylum first shows true segmentation?
Annelida
What type of circulatory system do annelids have?
Closed circulatory system
What type of symmetry do sponges (Porifera) mostly have, and why is it irregular?
Asymmetrical; because their body has no fixed shape or organized structure
What is the function of the gastrovascular cavity in cnidarians?
Digestion and distribution of nutrients
Why is cephalization not present in radially symmetrical animals like cnidarians?
Because they interact with the environment from all directions, so no head is needed
What is the main role of the pseudocoelom in nematodes?
It acts as a space for organ development and helps distribute nutrients
Why do flatworms rely on diffusion for respiration?
Because they lack specialized respiratory and circulatory systems