Introduction

Question 1

Invertebrates

Answer 1

Organisms without a vertebral column (no backbone)

Question 2

Challenges faced by all animals

Answer 2

• Locomotion
• Environmental constraint (temp, humidity, staying out)
• food/nutrition
• prey and predation
• sex and love

Question 3

Natural selection=

Answer 3

Variation + differential reproduction+ heredity

Question 4

Invertebrate classification methods

Answer 4

1. Number of cells
2. General body form
3. Developmental pattern
4. Evolutionary origins
5. Genetic origins

Question 5

Based on number of cells

Answer 5

• acellular (no cells) virus
• unicellular (one called) protozoans
• multicellular (many cells)

Question 6

General body form

Answer 6

• asymmetry: lack of any form of symmetry, uncommon. Ex: marine sponge
• bilateral symmetry: spouted into 2 halves that are mirror images of each other from mid line. Ex: insects and crabs
• radial symmetry: splitting in either midline or perpendicular result in division into approximate equal halves

Question 7

Developmental pattern is based on

Answer 7

Number of germ layers in embryogenesis

Question 8

Developmental pattern types

Answer 8

Diploblastic: possess 2 germ layers (ectoderm and endoderm) ex: cnidarians

Tripoblastic: possess 3 germ layers (ectoderm, endoderm and mesoderm) ex: most metazoans

Question 9

Ectoderm
Endoderm
Mesoderm

Answer 9

Outer layer giving rise to skin

Inner layer giving rise to organs

Middle layer giving rise to muscles and circulatory systems

Question 10

Coelomates

Answer 10

Form a large and diverse group of invertebrate animals with 3 germ layers. They have an internal fluid filled cavity known as a coelom, positioned between the gut and the outer body wall musculature and lined with tissues from the embryonic mesoderm.

Question 11

3 categories of coelomates

Answer 11

Eucoelomates (true coelom)
Pssudocoelomates (false Coelom)
Acoemates(no coelom)

Question 12

True coelom cross section

Answer 12

Surrounded by tissues from the embryonic mesoderm

Question 13

Pseudocoelom cross section

Answer 13

Not surrounded by tissues from the mesoderm

Question 14

Cross section of acoelomate

Answer 14

Space between the guy and ectoderm is entirely filed with tissues from the embryonic mesoderm

Question 15

Coelom formation

Answer 15

May arise from 2 distinct mechanisms based on embryonic differences of origin of the mouth (stoma)

• protostomes
• deuterostomes

Question 16

Protostomes

Answer 16

(First mouth): mouth developed from the first opening during embryonic development. Coelom develops from gradual enlargement of a split in the mesoderm by a process called schizocoely

Question 17

Deuterostomes

Answer 17

(Second mouth): mouth formed not from first opening of the embryo but subsequent openings. Abha could be formed from first opening. Coelom develop from e vagina toon of the archenteron into the embryonic blastocoel, resulting in gut formation by a process called enterocoely

Question 18

Taxon

Answer 18

Any names group of organism which vary significantly from other members

Question 19

Monophyletic

Polyphyletic

Answer 19

Members arising from a single ancestor

Members arising from multiple ancestors

Question 20

Taxon classification

Answer 20

Kingdom 
Phylum 
Class
Order
Family
Genus 
Species (capable of interbreeding)

Question 21

Binomial nomenclature

Answer 21

Based on identifying living organisms by two names known as generic and specific

• first letter of generic must be capitalized
• specific name must be non capital
• both names must be Italicized or underlined