What is an essential feature required for the origin of multicellularity?
ANS: The origin of multicellularity requires the evolution of new ways for cells to adhere (attach) and signal (communicate) to each other
2. What are animals? List all their defining features.
ANS: There are heterotrophs that ingest food, they lack cell wall, they have collagen, unique nervous and muscle tissue. They have a different symmetry of their bodies, also they posses a body cavity called coelom
3. Differentiate protostomes and deuterostomes.
ANS: In protostomes, the first opening (blastopore) becomes the mouth, while in deuterostomes, it becomes the anus.
4. What are the five important points about living animals that are reflected in their phylogeny? Explain the terms you might use like “basal”, “true tissues”, bilateral, etc.
ANS: Radical symmetry(no front or back), Bilateral symmetry(they have a dorsal, ventral, front and back), Tissues(collection of of special isolated cells), body cavities(derived from mesoderm)
5. What is the relationship between animal size and shape? Give an example of an aquatic animal and a terrestrial animal in discussing that relationship.
ANS: Size and shape affect the way an animal interacts with its environment. In aquatic animals, Properties of water limit possible shapes for fast swimming animals,
6. What is a key problem for survival faced by multicellular organisms that single celled organisms do not have? How does this relate to exchange with the environment?
ANS: Multicellular organisms have body walls that are two cells thick, making it hard to exchange with the environment. Single celled organisms has sufficient surface area to carry out all necessary exchange
7. Why is interstitial fluid important?
ANS: allows movement in and out of the cell
8. What are the four main categories of animal tissues? Define them and give an example of each.
ANS:
Epithelial tissue: covers the outside of the body and lines the organ within the body. An example is the stomach
Connective tissue: bind and support other tissues. An example is the tendons
Muscle tissue: responsible for body movement