10.1 Introduction to animals

Question 1

Animal characteristics?

Answer 1

1. Eukaryotes (true nucleus + membrane bound organelles)
2. Heterotrophic
3. Mutlicellularity
4. No cell walls
5. Motile at some life stage
6. Somatic (body) cells are diploid (2N)
7. Life cycle is dominated by diploid phase (diplontic - haploid phase being limited to gamete)
8. Most animals have tissues

Question 2

Modes of feedigng of animals?

Answer 2

Heterotrophic: Predators, herbivores, filter feeders, parasites, detritivores, omnivores

Question 3

Most animals have …. digestion

Answer 3

Internal

• As opposed to fungi
• Internal gut that is continuous with the outside environment and permits internal digestion of food item

Question 4

Advantages of multicellularity?

Answer 4

• Can become specialized
• Organism can grow in size

(If you are one large cell, you have a problem because you have a low surface to volume ratio)

Question 5

Without cell walls, how do animal support their body?

Answer 5

1. Hydrostatic skeleton (muscles constract against fluid-filled cavity)
2. Exoskeleton (non-living covering that doesn’t grow with animals - needs to get rid of it while growing to allow the new one to harden)
3. Endoskeleton (internal support, grows with you)
   a. Vertebrate (living tissue)
   b. Some invertebrates (non-living, ex. CaCO3)

Question 6

Advantages of motility?

Answer 6

Movement reduces competition, enhances genetic diversity

Question 7

What are tissues

Answer 7

Groups of similar cells organized into a functional unit

Question 8

Examples of tissues?

Answer 8

• Muscular
• Nervous
• Connective (reticular, adipose, blood, bone)
• Epithelial

Question 9

Tissues can function together as…

Answer 9

Organs (to complete more complex tasks)

Question 10

How many species of animals classified?

Answer 10

1+ million

Question 11

% of animals are invertebrates?

Answer 11

97

Question 12

When did animals evolve?

Answer 12

Late Precambrian

Question 13

What are the closes living relatives to ancestral animals?

Answer 13

Colonial …. (check slide)

Question 14

When did animals diversify?

Answer 14

Cambrian exposion

Question 15

Animals are a …. group

Answer 15

Monophyletic

• No other group shares all of these characterisitcs
• One common ancestor

Question 16

Evidence that animals is a monophyletic group?

Answer 16

• Similar gene sequences (Hox genes - involved in development and control identity of different body carts)
• Similar extracellular matrix (check slide)
• Unique types of junctions between cells (CHECK SLIDE FOR ALL EVIDENCE)

Question 17

Evolution of eukaryote in phylogeny?

Answer 17

As to include fungi and animals