Animal Diversity lecture 16 -Vertebrates

Question 1

Relatively how large and diverse is the group vertebrates

Answer 1

• small group (47,000 species) less than 1% of all animals
• Arthropods are as diverse as vertebrates with same range of habitats
• Molluscs have same range in size (snail -> colossal squid) + large brains

Question 2

How many orders (groups that show very distinct differences) of vertebrates are there

Answer 2

1) mammals (26)
2) Birds (23)
3) Reptiles (4)
4) Amphibians (3)

Question 3

What is an example of vertebrate diversity

Answer 3

1) Paedocypris - Worlds smallest fish (7.9cm) -> lives in very acidic peat swamps in sumatre. (endangered due to oil plantations
- Small size is maintained due to paedomorphisis, retain juvenile traits into adulthood and mature at a v small size

Question 4

Another example of vertebrate diversity

Answer 4

1) Blue Whale (33m), 5 orders of magnitude bigger than the smallest frog, vertebrates very variable in size.

Question 5

4 facts about vertebrates

Answer 5

1) large animals are usually vertebrates
2) energetically expensive existence requires different feeding modes
3) wide range of reproductive behaviours : eggs/live birth / no parental care
4) Important ecological role - at top of most food chains

Question 6

Evolution of terrestrial vertebrates

Answer 6

• 550 Mya, seperate continents
• 300 Mya , one single continent through merging of other continents (pangea)
• 150 Mya , Pangea broke apart

Question 7

Vicariance

Answer 7

The geographical separation of a population, typically through a physical barrier such as a mountain range, resulting a pair of closely related species.

Question 8

Examples of convergent evolution

Answer 8

1) body shape in icthyosaurs (reptile) , porpoises (mammal) and sharks (fish)
2) flight in bats + birds

Question 9

Examples of classification systems

Answer 9

• all classification systems based on similarities

1) Traditional, phenetic methods - equal weight given to all characters
2) Phylogenetic classification - weights characters depending on evolutionary origin

• not easy to distinguish homology and analogy (convergent evolution)

Question 10

what type of group are reptiles

Answer 10

paraphylectic , birds can be seen as a group of dinosaurs

Question 11

what % of vertebrates are endangered

Answer 11

20% , for each living vertebrate species there are about 100 extinct ones (reached maximum about 12-14 Mya)