Lecture 4: Diversity of Life- animals, phylogeny and evolution

Question 1

Classification System

Answer 1

Domain - Eukaryota
Kingdom - Animalia
Phyla
Class
Order
Family
Genus
Species

Question 2

Define animals

Answer 2

Multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers

Question 3

Define phylogeny

Answer 3

Branching diagram showing how species are related

Question 4

What is metazoa?

Answer 4

Sponges but do not have true tissue

Question 5

What is Eumatazoa?

Answer 5

Have true tissues

Question 6

Describe Porifera

Answer 6

5,500 species
Sessile - stuck to substratum at bottom
Mostly marine
Lack true tissue
Clumps of cells held together by collagen
Suspension feeders

Question 7

Describe Radiata

Answer 7

1st group of Eumetazoa
based on symmetry - can be split multiple ways
Include: Cnidaria (sea anemones, corals, hydra and jellyfish)
-> carnivores, feed using stinging cells called nematocysts

Question 8

Describe Bilateria

Answer 8

Rest of Eumatoazoa

Can be split down middle and be mirror image

Question 9

What is included in Deuterostomia?

Answer 9

Echinodermata

Chordates

Question 10

What are Echinodermata?

Answer 10

Starfish, sea urchins, sea lilies and sea cucumbers
Marine
Move and feed by water vascular system and tube feet
Bilaterally symmetrical as larvae and radically as adults

Question 11

What are Chordates?

Answer 11

Lancelets, hagfish, tunicates, vertebrates
Possess notochord - spine
Most are vertebrates
Contains animals

Question 12

What is included in Lophotrochoza?

Answer 12

Based on molecular data
Develop lophophore feeding tentacles or trochophore larvae

Platyhelminthes
Annelida
Mollusca

Question 13

What are Platyhelminthes?

Answer 13

Flatworms
No body cavity or organs for gas exchange
Includes: tapeworms and trematodes - parasite of humans

Question 14

What are Annelida?

Answer 14

Segmented worms
Mainly aquatic
2 main groups: polychaetes (Marine) and oligochaetes

Question 15

What are Mollusca?

Answer 15

Gastropods, bivalves, cephalopods
Often have shells
Well developed eyes
Cephalopods complex brains

Question 16

What is included in Ecdyozoa?

Answer 16

Secrete hard exoskeleton - moult as they grow
Defined on basis of molecular data - not moulting

Nemotoda
Arthropoda

Question 17

What are Nemotoda?

Answer 17

Roundworms
Very abundant in soil and freshwater
Covered in tough cuticle
Many parasites to plants and animals
Ex)Caenorhabditis elegans

Question 18

What are Arthropoda?

Answer 18

Crustaceans, insects and arachnids
Majority of identified species are arthropods
Segmented skeleton with jointed limbs

Question 19

Timeline of Animals

Answer 19

Neoproterozoic (~700 mya) - 1st animal evolved
-> earliest animal fossil are embryos in China
Ediacaran biota (565 mya) - contained mainly sessile or slow moving species
-> ex) Mawsonites spriggi, Dickensonia
Cambrian (535-525 mya) - many fossils of present day animal phyla