Lecture 16 - Rise of the invertebrates

Question 1

Invertebrate

Answer 1

They either have a soft body, like worms and jellyfish, or a hard outer casing covering their body, like spiders and crabs

Question 2

Vertebrate

Answer 2

Vertebrates are animals that have a backbone inside their body. The major groups include fish, amphibians, reptiles, birds and mammals.

Question 3

Chordata: what groups are part of this phylum and what do all Chordata have in common?

Answer 3

Vertebrates, Tunicates, Lancelets

Notochord - dorsal supporting rod
Pharyngeal slits near the throat
Dorsal hollow nerve chord
A tail extending beyond the anus

Question 4

Fishes: how many species and what is the diversity like?

Answer 4

The largest vertebrate group with about 33,000 species, ecologically and behaviourally diverse

Economically and ecologically important

Phylogenetically speaking, fish do not exist!

Question 5

Ray-finned fish morphology

Answer 5

Operculum - protects gills

Pectoral, pelvic, anal, and caudal fins - a greater degree of movement

Dorsal fins - a variety of functions, can be for movement but differentiates in many species to various functions: poison, bait, indigestible, etc

Lateral line - prey detection, spatial orientation, predator avoidance, schooling behaviour, intraspecific communication and station holding

Question 6

Challenges of life on land

Answer 6

Movement - fins useless
Support - no water to support body weight
Oxygen - gathering oxygen using the lungs
Food - finding food
Drying out - without water always prevalent, drying out is possible

Question 7

Lungfish

Answer 7

Lungs as well as gills - suggesting lungs grew before gills

Question 8

Development of fins to feet

Answer 8

From 380 mYa to 365 mYa, the fins slowly developed into feet and other such limbs in the organisms that would be the ancestors of mammals