Question

What are Animals? 1. List and briefly describe the defining features of animals. Be sure you understand these terms: eukaryote, heterotrophic, multicellular 2. Clearly show how the set of features listed in your answer to question 1 distinguishes animals from bacteria, fungi, plants and protists. 3. Describe the characteristics of true multicellularity in animals. Your answer should include: collagen (what is it, what does it do, etc.), gap junctions vs tight junctions, cell differentiation, totipotency and more. 4. To what extent are the characteristics of multicellularity given in question 3 shown by Volvox, sponges and cnidarians? 5. Define the term "division of labor" and give examples at the cell level, at the tissue level and at the organ level. 6. What is an epithelial layer? Why is their evolution considered to be signficant? 7. Define and briefly describe each of these basic animal functions: integument osmoregulation muscles and skeleton ionic regulation food capture sensory system digestion control systems gas exchange reproduction circulation development excretion

Answer 1

1) The defining features of animals are listed below,

• They are eukaryotes and multicellular organisms
• They are heterotrophs which means they obtain their energy by consuming energy rich food substances
• Their cells are surrounded by plasma membrane and cell wall is absent
• They are capable of locomotion
• Most of the animals reproduce sexually
• Animals respond rapidly to any external stimuli

2) Animals are multicellular while bacteria are unicellular. Animals are heterotrophic while plants are autotrophic and fungi are saprophytic.

Please post other questions separately.