Chordates

Question 1

What are the features of Echinoderms?

Answer 1

Loss of Pharyngeal slits. Radial symmetry as adults. Exclusively marine. Bilaterally symmetrical larvae. Calcified internal plates. No head in adults (oral and aboral surfaces). Tube feet allows locomotion and foraging.

Question 2

What are the features of Hemichordates?

Answer 2

Worm like. Marine. Two major groups and 3 main body parts. Breathing a gas exchange by pumping water through pharyngeal slits.

Question 3

What are the two major groups of hemichordates?

Answer 3

Acorn worms which live in burrows and sand. Pterobrachs which are smaller and some are colonial. They have 9 pairs of arms with behind collar used to capture prey.

Question 4

Give the three main body parts and their function

Answer 4

Proboscis is mucus covered to capture prey. The collar and the trunk.

Question 5

What are the features of the chordates?

Answer 5

Notochord, dorsal hollow nerve chord and post anal tail. The notochord is composed of large cells with thick fluid vacuole, it is rigid but flexible.

Question 6

What do urochordates and cepholochordates have in common

Answer 6

The majority are sessile. They have a bag like body enclosed in a tunic. Water pumped in through incurrent siphon to mouth. Food particles are moved by ciliary action.

Question 7

Describe the features of Cepholochordates

Answer 7

Found in sediment in shallow marine waters. An example is the lanclets. Filter prey from water suing pharyngeal baskets.

Question 8

Describe the features of urochordates

Answer 8

There are three major groups which are all marine. Ascideans, Thaliaceans, Larvaceans Many form colonies and can be up to several meters long.

Question 9

Describe the features of vertebrates

Answer 9

Vertebral column. Anterior skull. Large Brain. Ventral heart. Internal organs suspended in coelom.

Question 10

Describe the features of hagfish

Answer 10

Lack a vertebral column. Weak circulation (3 small hearts). No jaws or stomach. Produce lots of slime when feeding on rotting flesh.

Question 11

What are lampreys?

Answer 11

Class Hyperoartia . Most are either fresh water or migratory. Complete cranium and separate vertebrae. Adults are ectoparasitic on fish. The larvae filter feed.

Question 12

How did jaws evolve?

Answer 12

From skeletal arches allowing greater foraging efficiency and diversity.q

Question 13

Give the features of cartilaginous fish

Answer 13

Sharks, rays and skates, they have paired, medium and caudal fins. They have a cartilage skeleton and some are filter feeders but most are predators.

Question 14

What are the features of ray finned fishes

Answer 14

They are a very diverse group. Like cartilaginous fish they have paired, medium and caudal fins. They have a calcified bony skeleton with light weight scales. Buoyancy control. Gills open into a single chamber. Complex behaviours.

Question 15

Describe lobe-finned fishes

Answer 15

They have two pairs of muscular joined fins and a cartilage skeleton.

Question 16

Where are lung fishes predominantly found?

Answer 16

Africa and Australia. they have lungs.

Question 17

What are the different tetrapod’s

Answer 17

Amphibians which lose water rapidly and have three major groups: Caecillians, Anurans, Salamanders.
Reptiles e.g. turtles, lizards, snake and crocodilians.
Aves (birds) feathers allow them to fly.
Mammals which have sweat galnds, mammary glands, hair and a four chambered heart.

Question 18

Why adapt to use plants as a food source?

Answer 18

They are abundant, unexploited and there was a lack of competition.

Question 19

What were the problems for using plants?

Answer 19

The cellulose was difficult to chew through and could not be digested in the gut, unlike starch which is similar to glycogen.

Question 20

How have Jaws and teeth adapted for chewing plants?

Answer 20

Dental occlusion. Bone become stronger. Complex cusp pattern of molars and premolars develops for carnivores and herbivores. Herbivores have more molars and premolars which have ridges to improve grinding (crescent shaped and elongated).

Question 21

How are browsers and grazers teeth adapted?

Answer 21

Browsers have teeth have low crowns, finite growth. Grazers have high crowned teeth that are constantly growing

Question 22

What is the difference between hindgut fermentation and foregut ruminants?

Answer 22

Hindgut fermentation: enlargement of caecum

Foregut ruminants: enlargement of foregut and additional mechanical breakdown

Question 23

Describe the features of hindgut fermentation

Answer 23

Faster digestion. Cellulose not fully broken down. Suits high starch, low energy food. Used by very small and very large animals.

Question 24

Give the definition for adaptive radiation

Answer 24

The rapid evolution from a common ancestor of several species that occupy different ecological niches’. For example Darwin’s finches from Dull coloured grassquit

Question 25

What are the three main groups of mammals?

Answer 25

Marsupials for example the red kangaroo.
Monotremes are egg laying mammals.
Placental are everything else.

Question 26

What is a trophic morph?

Answer 26

A body or head shape, usually related to foraging ecology, that is unique within the group

Question 27

What did the experiment into African cichlid fish show?

Answer 27

Lake surface area was an important predictor of species diversity
But younger lakes had more species than expected
Suggests radiations explode, then slow…

Question 28

How did the two morphs in sticklebacks form?

Answer 28

Sympatric speciation through competition for limited food
or
Allopatric speciation by way of a ‘double invasion’.

Question 29

In what ways is the feeding niches reflected?

Answer 29

Body form, particularly the form of the skull, jaws & teeth