Lecture 4: Diversity of Life- animals, phylogeny and evolution Flashcards
Classification System
Domain - Eukaryota Kingdom - Animalia Phyla Class Order Family Genus Species
Define animals
Multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers
Define phylogeny
Branching diagram showing how species are related
What is metazoa?
Sponges but do not have true tissue
What is Eumatazoa?
Have true tissues
Describe Porifera
5,500 species Sessile - stuck to substratum at bottom Mostly marine Lack true tissue Clumps of cells held together by collagen Suspension feeders
Describe Radiata
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
Describe Bilateria
Rest of Eumatoazoa
Can be split down middle and be mirror image
What is included in Deuterostomia?
Echinodermata
Chordates
What are Echinodermata?
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
What are Chordates?
Lancelets, hagfish, tunicates, vertebrates
Possess notochord - spine
Most are vertebrates
Contains animals
What is included in Lophotrochoza?
Based on molecular data
Develop lophophore feeding tentacles or trochophore larvae
Platyhelminthes
Annelida
Mollusca
What are Platyhelminthes?
Flatworms
No body cavity or organs for gas exchange
Includes: tapeworms and trematodes - parasite of humans
What are Annelida?
Segmented worms
Mainly aquatic
2 main groups: polychaetes (Marine) and oligochaetes
What are Mollusca?
Gastropods, bivalves, cephalopods
Often have shells
Well developed eyes
Cephalopods complex brains
What is included in Ecdyozoa?
Secrete hard exoskeleton - moult as they grow
Defined on basis of molecular data - not moulting
Nemotoda
Arthropoda
What are Nemotoda?
Roundworms Very abundant in soil and freshwater Covered in tough cuticle Many parasites to plants and animals Ex)Caenorhabditis elegans
What are Arthropoda?
Crustaceans, insects and arachnids
Majority of identified species are arthropods
Segmented skeleton with jointed limbs
Timeline of Animals
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
