Lecture 4. Introduction to Animal Diversity Flashcards
How is an animal classified ?
- Domain
- Kingdom
- Phyla
- Class
- Order
- Family
- Genus
- Species
What are animals ?
Multicellular, heterotrophic, eukaryotes with tissues that develop from embyronic layers
What does heterotrophic mean ?
They obtain organic compounds by ingesting or absorbing them
What are tissues ?
Groups of cells with a common structure function or both
What types of tissues are unique to animals ?
Muscles and nerve tissues
What is a phylogeny ?
A branching diagram showing how species are related
How are phylogenies constructed ?
By looking at similarities and differences among species physical and or genetic characteristics
What do nodes show ?
- The ancestor of the group
2. Evolutionary transitions
What are animals traditionally characterised by ?
A number of different body plans
What do eumetazoa have ?
True tissues
What are some examples of eumetazoa ?
- Porifera
- Ctenophore
- Cnidaria
- Acoela
- Echinodermata
- Chordata
- Platyhelminthes
- Rotifera
- Ectoprocta
- Brachiopoda
- Mollusca
- Annelida
- Nermatoda
- Arthropoda
How many species of porifera are there ?
5500
What is another name for porifera ?
Sponges
What type of movement is associated with porifera ?
Sessile
What do porifera lack ?
True tissue
How would you describe the structure of porifera ?
Clumps of tissue held together by collagen
What type of feeders are porifera ?
Suspension feeders
Which types of eumetazoa are considered radiata ?
- Porifera
- Ctenophora
- Cnidaria
- Acoela
Which eumetazoa are considered bilateria ?
- Echinodermata
- Chordata
- Platyhelminthes
- Rotifera
- Ectoprocta
- Brachiopoda
- Mollusca
- Annelida
- Nermatoda
- Arthropoda
What are cnidaria ?
Sea anemones, corals, hydra, jellyfish
How many types of cnidaria are there ?
10,000 species
What type of feeders are cnidaria ?
Carnivores
How do cnidaria feed ?
Using stinging cells called nematocysts
What are the deuterostomia ?
- Echinodermata
2. Chordata
What are some examples of echinodermata ?
Starfish, sea urchins, sea lillies, sea cucumber
How many species of echinodermata are there ?
7000 species
How do echinodermata move and feed ?
Using a water vascular system and tube feet
What is interesting about the symmetry of echinodermata ?
They are bilaterally symmetrical as larvae but radially symmetrical as adults
What are some examples of chordates ?
Lancelets, hagfish, tunicates, vertebrates
How many species of chordata are there ?
52000
What do chordates possess ?
Notochord
What are most chordata ?
Verterbrates
What are lophotrochozoa ?
- Platyhelminthes
- Rotifera
- Ectoprocta
- Brachiopoda
- Mollusca
What do many lophotrochozoa have or develop ?
Lophophore feeding tentacles or have trochophore larvae
What is an example of platyhelminthes ?
Flatworms
How many species of platyhelminthes ?
20 000
What do platyhelminthes not have ?
No body cavity or organs for gas exchange
What are annelida ?
Segmented worms
How many species of annelida are there ?
16500
What are annelida preferred environment ?
Mainly aquatic
What are the two types of annelida ?
- Polychaetes
2. oligochaetes
What are mollusca ?
Gastropods, bivalves, cephalopods
How many species of mollusca are there ?
93000
What do molluscas have ?
Shells
What is unique about mollusca’s eyes ?
They are very well developed
What do cephalopods have ?
Particularly complex brains for invertebrates
What are ecdysozoa ?
- Nematoda
2. Arthropoda
What do ecdysozoa secrete ?
A hard exoskeleton which they moult as they grow
What is the ecdysozoa clade defined by ?
On the basis of molecular data not the moulting characteristics
What are nematoda ?
Roundworms
What are arthropoda ?
Crustaceans, insects, arachnids
How many species of arthropoda are there ?
1000000
What is the structure of an arthropoda ?
Segmented skeleton with jointed limbs
When did the first animals probably evolve ?
During the neoproterozoic period
What is the time frame for the neoproterozoic period ?
700 million years ago
Where are the earliest animal fossils from ?
China
When did many fossils of present day animal phyla appear ?
The Cambrian explosion
When was the cambrian explosion ?
535 - 525 million years ago
Where does most of our knowledge about Cambrian animals come from ?
- Burgess shale in Canada
2. Chengjiang in China
What is the earliest known chordata ?
Pikaia
Why was their a sudden increase in animal diversity in the Cambrian ?
- Increased oxygen levels, increased metabolic rates and allowed species to grow larger and more complex.
- The evolution of the Hox genes, allowed different developmental pathways to be used and facilitated the evolution of new body forms
- Increases in the number and variety of predators drove selection for anti-predator defences