#10 - Kingdom animalia Flashcards
What are the main characteristics shared by all animals?
They are eukaryotic, multicellular organisms, lack cell walls, are heterotrophs, are mobile for at least one stage of life, and reproduce sexually.
What distinguishes vertebrates from invertebrates?
Vertebrates have a backbone, while invertebrates lack a backbone.
What are the three layers of cells that develop from a blastula in animals other than sponges and cnidarians?
- Ectoderm (outer layer) produces skin, nerve tissue, sense organs
- Mesoderm (middle layer) produces lungs, liver, pancreas, bladder, gut lining
- Endoderm (inner layer) produces muscles, blood, kidneys, reproductive organs
What is a blastula?
A hollow ball of cells that develops into three distinct layers giving rise to all organs and tissues.
What type of symmetry do sponges exhibit?
Asymmetrical.
What are the two types of symmetry found in most animals?
- Radial Symmetry: organized equally around a vertical axis
- Bilateral Symmetry: can be cut into two equal, mirror-image halves through one vertical plane
What is a coelom?
An internal fluid-filled body cavity that provides rigidity and support.
What are the two types of animals based on the presence of a body cavity?
- Coelomate: animals with a body cavity
- Acoelomate: animals without a body cavity (e.g., cnidarians, flatworms)
What is segmentation in animals?
The division of the body into repetitive sections.
What are the two advantages of segmentation?
- One damaged segment does not affect another
- Improved mobility since segments move independently
What does it mean for an organism to be sessile?
It means the organism is stationary as an adult.
Can sessile organisms be mobile during any stage of their life?
Yes, they can be mobile during juvenile stages.
What are the two methods of sexual reproduction in organisms?
- External fertilization
- Internal fertilization
