Lecture 10: Intro To Animals

Question 1

Animal Characteristics: Eukaryotic

Answer 1

• comes from word true nucleus

- has membrane bound organelles

Question 2

Animal Characteristics: Heterotrophic

Answer 2

• use organic molecules for energy and carbon source

- have internal digestion with internal continual gut (not sponges tho)

Question 3

Animal Characteristics: Multicellular

Answer 3

• means you can grow in size
• means you can have cells have specific functions
• multicellularity helps large cells (that have low SA t V ratio) overcome their constraint on constant growth.

Question 4

Animal Characteristics: No cell walls

Answer 4

Need support by skeletons:
A) hydrostatic skeleton: muscles contract against fluid filled cavity
B) Exoskeleton: non- living covering that doesn’t grow with the animal
C) Endoskeleton: internal support (mostly vertebrate, and some invertebrates)

Question 5

Animal Characteristics: Motile at some life stage

Answer 5

• movement reduces competition & enhances genetic diversity

Question 6

Animal Characteristics: Have somatic body cells

Answer 6

they are diploid

Question 7

Animal Characteristics: Diplontic

Answer 7

mainly diploid life form (as opposed to sponges that are haplontic)

Question 8

Animal Characteristics: Have tissues

Answer 8

• groups of similar cells organized into a functional group

- they can function together and perform more complex tasks

Question 9

What are animals closest living relative?

Answer 9

Choanoflagellate- filter feeders

Question 10

Cambrian Explosion

Answer 10

• in a blink of an eye there was rapid diversification

Question 11

Are animals monophyletic?

Answer 11

• derived from same ancestor
• have similar gene sequence (ex. hox genes)
• similar extracellular space
• have unique types of junctions

Question 12

Types of junction

Answer 12

tight junction: in between epithelial cells
desmosomes: allow connection of cytoskeleton
gap junction: allow rapid communication (in muscles and nerve cells)

Question 13

Sponges (Porifera)

Answer 13

• pore bearing
• sessile as adults
• motile as larvae
• filter feeders

Question 14

Support structures

Answer 14

• Extracellular matrix: made of collagen glycoproteins
• Spicules: provide rigidity, made of CaCO3
• Spongin: provide flexibility, made of protein fibres

Question 15

Reproduction of Sponges

Answer 15

Asexual: fragmentation or budding
Sexual: hermaphroditic (eggs produced in amoebocyte or choanocyte, broadcast the sperm, settle on suitable substrate)