Animal biodiversity 2 - invertebrates

Question 1

what is the simplest most primitive animals?

Answer 1

phylum porifera - sponges

Question 2

what are 4 features of the parazoa?

Answer 2

1) no gastrulation
2) no true tissues
3) some specialised cells
4) lack muscles/nervous system/organs

Question 3

describe the reproductive strategy of sponges

Answer 3

reproduce sexually as hermaphrodites. fertilisation occurs in the mesohyl as sperm are carried out by current, flagellated zygotes settle on suitable substrate

Question 4

what is the next group up from the metazoan and what phylum does that include?

Answer 4

the eumetazoa (radiata) including phylum cnidaria (jellyfish)

Question 5

what are the 2 types of eumetazoa?

Answer 5

1) sessile polyp (mouth up)

2) floating medusa (mouth down)

Question 6

what symmetry and how many embryonic layers do eumetazoas have?

Answer 6

radial symmetry and diploblastic (2 layers)

Question 7

what are 3 features of cnidaria?

Answer 7

1) no brain
2) simple nervous system
3) mouth and anus are the same gastrovascular cavity

Question 8

what are they feeding habits of eumetazoas?

Answer 8

they are carnivores which catch their prey by tentacles piercing prey and releasing venom

Question 9

what are the 4 groups of eumetazoas and their forms?

Answer 9

1) hydrozoan - regenerate alternating between polyp and medusa form
2) scyphozoan - medusa stage is predominant
3) cubozoan - medusa stage
4) anthozoan - polyps

Question 10

what are the 2 groups of the protostomia?

Answer 10

• Lophotrochozoa

- Ecdysozoa

Question 11

what are 2 features of protostomes?

Answer 11

1) characteristic cell division and coelom formation, early cell determination and mouth forms first
2) ventral nerve cord

Question 12

what forms first in protostomes?

Answer 12

the mouth

Question 13

what is the phylum platyhelminthes?

Answer 13

flat worms

Question 14

do flat worms have a coelom?

Answer 14

no it is believed they used to have one but lost it in evolution

Question 15

how many tissue layers do platyhelminthes have?

Answer 15

3 triploblastic

Question 16

what are 3 features of lopotrochozoa?

Answer 16

1) mesoderm contains true organs and muscles
2) sensory/motor development
3) lack gas exchange and circulatory organs

Question 17

what are the 5 reasons the evolution of a well developed coelom is so important?

Answer 17

1) hydrostatic skeleton
2) body space for storage and organ development
3) cushion for organs
4) buffers body wall muscle actions from muscles in digestive tract
5) allows for specialisation of regions of the body

Question 18

what is the problem with the new zealand flatworm and what are its predators?

Answer 18

they were imported by accident and eat earth worms which are good for the soil, ground beetle larvae eat them

Question 19

what are trematoda and what is their lifecycle?

Answer 19

parasitic flukes which lifecycle involves intermediate hosts

Question 20

what is the lifecycle of cestoidea (parasitic tape worms)

Answer 20

they attach to primary hosts intestines and reproduces

Question 21

what is the phylum Annelidia and 3 features?

Answer 21

segmented worms

1) blood vessels in closed circulatory system
2) coelom divided by septa
3) digestive tract has specialised regions

Question 22

how do earth worms reproduce?

Answer 22

hermaphrodites which cross fertilise but can also reproduce asexually by fragmentation

Question 23

what is the body structure of leeches?

Answer 23

dorsally flattened, reduced segmentation and coelom

Question 24

define an invertebrate

Answer 24

animals that lack a backbone

Question 25

how do sponges feed?

Answer 25

suspension feeders - capture food particles suspended in water drawn through the spongocoel and flows out osculum

Question 26

what are choanocytes?

Answer 26

collar cells with flagella that generate water current and trap food which line the spongeocoel

Question 27

4 features of class turbellaria

Answer 27

1) regenerate or reproduce sexually
2) hermaphrodites
3) eyespots detect light
4) gastrovascular cavity with complex folding

Question 28

what are 3 classes of annelids?

Answer 28

1) earthworms
2) marine segmented worms
3) leeches

Question 29

which has more sub species platyhelminthes or annelids?

Answer 29

platyhelminthes