Lecture 10

Question 1

Animal Characteristics (7) (EHMW

Answer 1

• Eukaryotic
• heterotrophic
• multicellular
• no cell wall
• diplontic
• somatic cells are diploid
• motile at some point
• many, not all have internal digestion (continuous tube)

Question 2

Eukaryotic

Answer 2

membrane bound organelles

true nucleus

Question 3

Heterotrophic

Answer 3

• different feeding
• use pre-formed organic materials as E and C course
• modes of feeding: herbivores, carnivores, filter feeders, parasites, detritivores, omnivores

Question 4

Multicellular (3 benefits)

Answer 4

• cells are specialized
• organisms can grow in size
• one large cell, low surface area to volume ratio, multicellularity helps overcome this constraint on growth

Question 5

No cell wall

Answer 5

• hydrostatic skeleton
• exoskeleton
• endoskeleton

Question 6

Hydrostatic skeleton

Answer 6

• muscles contract against fluid-filled cavity

- ex. worms

Question 7

exoskeleton

Answer 7

• external
• non living covering that does not grow with animal
• ecdysozoans

Question 8

ecdysozoans

Answer 8

moulting animal

Question 9

endoskeleton

Answer 9

• internal support
• vertebrates
• some inverterbrates (CaCO3)

Question 10

Motile at some life stage (benefits of that? (2))

Answer 10

• reduce competition

- enhance genetic diversity

Question 11

somatic (body cells) are diploid

Answer 11

• undergoes meiosis to produce haploid cells

- fuse to form zygote

Question 12

diplontic

Answer 12

fungi, haplontic
plant, alternating
animals, diplontic

Question 13

most animal has tissues

Answer 13

tissues = groups of similar cells organized into a functional group 
function as organs to complete complex tasks

Question 14

Origin of Animal (When? Closest living?)

Answer 14

First animal: 1.2 BYA - 700 MYA, marine

closest living relative to animal are colonial choanoflagellate protists

Question 15

Animal Diversification (What happened?)

Answer 15

• “Cambrian explosion”
• 542 - 488 MYA
• rapid diversification
• many fossils found in Burgess Shale, BC

Question 16

animals are monophyletic (one common ancestor) Evidence?

Answer 16

similar gene sequences
similar extracellular matrix molecules
unique types of junctions between cells

Question 17

Tight Junction

Answer 17

• abundant in epithelial cells
• bound tightly together
• cell-cell attachment structure that links the plasma membranes of adjacent animal cells
• forms a barrier to restrict movement of substances in the space between the cells

Question 18

Desmosomes

Answer 18

• connection btwn cytoskeletons

- attaches cytoskeleton of adjacent animal cells together

Question 19

Gap Junctions

Answer 19

• connect cells to cells
• directly connects the cytoskeleton of adjacent cells
• allows the passage of water, ions, and small molecules between the cells
• found in muscle and nerve tissues
• allows rapid communication between cells

Question 20

Sponges (Porifera) (pore bearing)

Answer 20

• 9000 (mostly marine)
• sessile as adults, motile as larvae
• spicules and a network of elastic fiber for support
• morphology is variable

Question 21

Filter Feeding

Answer 21

Choanocyte is similar to choanoflagellate
water goes through the pores and is pumped out from the osculum
cells are embedded in a jelly matrix
There is no true tissue (other than epithelial) or organs

Question 22

Support structures - Sponges

Answer 22

extracellular matrix
spicules
spongin

Question 23

extracellular matrix - Sponges (3)

Answer 23

• non cellular
• support
• collagen, glycoproteins

Question 24

spicules

Answer 24

• made of CaCO3, SiO2

- provides rigidity

Question 25

spongin

Answer 25

• flexible support

- protein fibres

Question 26

Asexual reproduction

Answer 26

Fragmentation 
- bought by waves or predators 
- not self induced 
Budding 
- clone of parent

Question 27

Sexual reproduction

Answer 27

• Hermaphroditic
• sperms and eggs produced in chanocytes or amoebycyte
• boardcast sperm
• eggs are fertilized and developed in extracellular matrix
• larvae released –> settle in suitable substrate