animalia

Question 1

characteristics of an animal

Answer 1

eukaryotic
- cell nucleus enclosed in membrane
- plants, algae, fungi and animals

opisthokont
- single posterior flagellum
- extracellular digestion
- fungi and animals

metazoan
- multicellular
- differentiated tissues specialised by function

consume organic matter
consume oxygen
move
reproduce sexually
develop from blastula (some exceptions)

Question 2

choanoflagellata

Answer 2

unicellular eukaryote
both free living and colonial
funnel shaped collar
sexual and asexual reproduction

*not animals

Question 3

ur metazoan

Answer 3

last common ancestor of all animals

first multicellular animals
eukaryotes
flagellate
marine
2 cell layers
no symmetry

Question 4

basal metazoans

Answer 4

asymmetrical or radially symmetrical
2 layers of cells (interior and exterior)
no organs, some differentiation of tissues

Question 5

porifera

Answer 5

basal metazoans - sponges

2 layers of cells
no tissues or organs
no symmetry

3 classes
- calcarea
- hexactinellida
- demospongiae

Question 6

class calcarea

Answer 6

calcareous sponges
rayed spicules composed of calcium carbonate
abundant in shallow water as need firm substrate

Question 7

class hexactinellida

Answer 7

glass sponges
spicules are 6 rayed and siliceous
deep water in extreme cold

Question 8

class demospongiae

Answer 8

demo sponges (95%)
spicules are siliceous but not 6 rayed
all depths

Question 9

respiration of proifera

Answer 9

aquifers system
- brings water through sponge
- pulled in though ostia
- driven across choanoderm by beating of flagella
- choanocytes pump large volumes of water through body at low pressure = water current established

water flows close to cells responsible for food gathering and gas exchange
waste expelled via osculum

Question 10

reproduction of porifera

Answer 10

sexual or asexual
hermaphodites

sexual
- produce eggs and sperm at different times
- produced by choanocytes and released via aquifers system
- oviparous and viviparous species
- larval ecology typically split by habitat - littoral or subtotal

asexual
- fragmentation
- budding
- asexual larvae

Question 11

placozoa

Answer 11

simplist structure of all animals
2 layers of cells
diploblastic, no mesoderm

reproduce via asexual budding

Question 12

coelenterates

Answer 12

paraphyletic roup
containing cnidaria and ctenophora

Question 13

ctenophora

Answer 13

coelenterates (eumetazoa)

comb jellies
radial symmetry
2 layers of cells

unique colloblast cells - sticky and used to capture prey
swim using cilia
bioluminescent

Question 14

cnidaria

Answer 14

coelenterates (eumetazoa)

anemones, clownfish, crabs, corals and green algae

sessile, sedentary or pelagic
occur at all depths

entirely aquatic and mostly marine
bioluminescent

Question 15

key characteristics of cnidaria

Answer 15

radially symmetrical
diploblastic - 2 layers of cells
single body cavity
no nervous system - nerve net

alternation of generations
- asexual polyploid and sexual medusoid stages

process cnidae

Question 16

alternation of generations of cnidaria

Answer 16

polyploid phase
- all classes
- sessile
- can reproduce asexually

medusoid phase
- medusozoa only, includes sea jellies
- free swimming
- reproduces sexually, usually dioecious (2 separate sexes)

Question 17

cnidae/nematocysts of cnidaria

Answer 17

stinging cells on sea jellies
used to trap prey for digestion
single use
used in feeding and defence

3 types:
penetrant - pierces and envenoms
glutinant - stick to prey
volvent - coils around prey