Lecture 17. A

Question 1

how many species have been identified until today and how many species are estimated to exist?

Answer 1

> 1 million species identified so far

Estimated 10-200 million species exist

Question 2

Most are __?

Answer 2

invertebrates (97%)

Question 3

Characteristics of ALL animals

Answer 3

Eukaryotic, no cell wall
Multicellular
Heterotrophic

Question 4

all animals except __ have Nervous & muscle & tissue

Answer 4

sponges

Question 5

kinds of symmetry in animals?

Answer 5

Asymmetrical

Radial (ex. phylum Cnidaria) Body can be cut into identical halves in more than 1 plane

BILATERAL only 1 cut along 1 plane results in 2 similar halves

Question 6

which symmetry do most animals have

Answer 6

bilateral (only 1 cut along 1 plane results in 2 similar halves)

Question 7

which of our organs regenerates tissues to some extent?

Answer 7

liver

Question 8

animals Challenges to living on Land/ in water: Water loss

Answer 8

In water: Not a problem
On land: Can dry out (desiccation)
(waxy cuticle in invertebrates, tough skin in vertebrates)

Question 9

animals Challenges to living on Land/ in water: Gas exchange

Answer 9

in water: Diffusion for simple animals, respiratory systems for others
On land: Reduced due to waxy cuticle. (lungs, tracheal tubes) NB wrt O2: more on land than in water

Question 10

animals Challenges to living on Land/ in water: Structural support

Answer 10

In water: not a problem

On land: Gravity may cause collapsing (skeletal system)

Question 11

animals Challenges to living on Land/ in water:Reproduction

Answer 11

in water: flagellated gametes swim to egg or internal fertilization
on land: Internal fertilization (except for amphibians)

Question 12

animals on land characteristics

Answer 12

Land
potential for drying out (desiccation), temperature change
Need support against gravity
Most animals live on land

Question 13

animals in ocean characteristics

Answer 13

In the ocean
Relatively stable temperatures, food, fluid
Disadvantages: Currents

Question 14

animals in fresh water characteristics

Answer 14

Fresh water

Less constant environment, osmoregulation (get rid of excess water) required

Question 15

how many major animal phyla

Answer 15

9

Question 16

which phyla of animals have no blood (no circulatory system)?

Answer 16

the first 4

1. porifera : sponges
2. cnidaria : jelly fish
3. flat worms
4. round worms

Question 17

which phyla of animals have a backbone?

Answer 17

chordate

Question 18

animal phylum and an example of each?

Answer 18

1. porifera : sponges
2. cnidaria : jelly fish
3. flat worms
4. round worms
5. molluscs: snails
6. segmented worms: earth worms
7. arthropods: spiders
8. echinoderms: starfish
9. chordates: birds

Question 19

75% of animals are in the phylum __?

Answer 19

Arthropoda (Exoskeletons invertebrates)

Question 20

how long did the Cambrian explosion last?

Answer 20

10 million years

Question 21

what is the cambrian explosion

Answer 21

Cambrian explosion: abrupt appearance of major animal groups
only 2 phyla present before the Cambrian explosion (fyi porifera ie sponges & Cnidaria ex jellyfish) ie only water-dwelling animals
Almost all living animal phyla appeared within a few millions of years.

Question 22

Appearance of animals?

Answer 22

LAND PLANTS, THEN LAND ANIMALS. BCUZ ANIMALS EAT PLANTS

Question 23

Physiological systems: 3 Skeletons

Answer 23

Exoskeleton: external, surface
Endoskeleton: internal (in vertebrates)
Hydrostatic skeletons: fluid under pressure in a closed body compartment

Question 24

Exoskeleton and its function?

Answer 24

external, surface (since this is the type of skeleton in invertebrates, it is the most common type of skeleton)
Support, protection

Question 25

Endoskeleton and its function?

Answer 25

internal (in vertebrates) | Support, protection of internal organs, movement, store minerals

Question 26

Hydrostatic skeletons and their function?

Answer 26

fluid under pressure in a closed body compartment | movement

Question 27

External Fertilization in vertebrates?

Answer 27

``` Most fish (cold-blooded) - Sharks have internal fertilization ``` Amphibians (cold-blooded) frogs

Question 28

Internal Fertilization

Answer 28

Reptiles (cold-blooded) Birds (warm-blooded) Mammals (warm-blooded)

Question 29

Amniotes?

Answer 29

vertebrates which have a fetal tissue known as the amnion, which surrounds and protects the fetus Reptiles, birds, mammals

Question 30

Amniotic cavity with fluid function

Answer 30

protects from injury & dehydration (no desiccation of developing offspring) Yolk sac: nutrients (like the seed)

Question 31

How do the embryos breathe inside the amniotic eggs?

Answer 31

through the pores

Question 32

5 Criteria of classification of animals?

Answer 32

Tissue organization: present or absent Body symmetry & development Body cavity * Embryonic development Segmentation

Question 33

if an organism has no true tissues, it belongs to which phyla?

Answer 33

No true tissues: Phylum Porifera (sponges)

Question 34

90% of chordates are __

Answer 34

vertebrates

Question 35

Placenta? its function?

Answer 35

Organ of exchange (food, wastes) between mom & developing embryo Allows young to stay in mom until embryonic development complete or almost complete

Question 36

oviparity?

Answer 36

expulsion of undeveloped eggs rather than live young

Question 37

viviparity?

Answer 37

Placental mammals

Question 38

The distinction between sponges and other animal phyla is based mainly on the absence versus the presence of

Answer 38

true tissues