Invertebrate symmetry+segmentation
- Created by: Louis James
- Created on: 10-01-13 16:54
Fullscreen
Biological diversity - invertebrate symmetry+segmentation
- eukaryotic
- cells - organelles, nucleus containing genetic material+no chloroplasts
- lack rigid cell walls
- store carbohydrates - glycogen
- multicellular
- body cells - arranged - form tissues eg nervous system
- tissues - arranged - form organ systems eg vascular system
- diploid
- body cells - contain duplictae chromosomes
- heterotrophic
- must obtain enery+carbon - ingesting other animals/absorbing nutrients - environment
- aerobic respiration
- requires oxygen
- reproduction
- sexual+asexual
- embryonic cells
- ectoderm
- endoderm
- mesoderm
- life cycle
- motile - part lif cycle
- stages - embryonic development, mitotic division transforms cell - multicellular embryo
- growth, survival+reproduction+(disperal+sexual reproduction)
- sponges (complex multicellularity)
- Cnidarians - distinct tissues
- Platyhelmids - high levels - tissue specialisation
- roundworms - body cavity
- insects
- organisms - true comple multicellularity:
- Parazoans (sponges)
- true multicellularity - not tissue development
- lack symmetry
- larval stage = free swimming
- adults = sessile
- distinct tissues alter life cycle - organism?
- animals - sub-kingdom eumetazoa, sub-group radiata, phylum cnidaria
- 4 classes: hydroids, sea anemones, jellyfish+corals
- inner endoderm+outer ectoderm formed - embryo
- 2 body forms - Cnidarians = polyp - medusa
- class Scyphozoa = jellyfish
- class Hydrozoa = hydroids
- both medusa+hydroid stages - life cycle
- most = marine+colonial
- well known hydroid = freshwater genus hydra - no medusa stage (exception)
- class Anthozoa = corals
- secrete exoskeletons - calcium carbonate
- form coral reefs - nutrient poor water - abundant algae found there
- fertilised eggs develop - planulae - settle into polyps, no medusa formed
- Anthoza includes se anemones
- plant like body, topped - tuft hollow tentacles
- harbour symbiotic algae
- highly muscular
- retract - touched
- kingdom - Animalia
- phylum (division)
- 30+ phyla (how divide them)
- based - body plan/ genetic relationship
- invertebrates
- no back bone
- Circa 2 million species
- vertebrates
- mammals, birds, reptiles, fish+amphibians
- 50000+ species
- Animalia
- body symmetry
- cephalisation
- type - gut
- type - body cavity
- segmentation
- Parazoans - simple multicellular animals lacking body tissues
- Eumetazoans
- radial symmetry - 2 layers tissue
- bilateral symmetry - 3 layers tissue
- sponges:
- no symmetry
- no tissues
- no organs
- tubular - not symmetrical
- variable shape
- very successful
- Cnidarians:
- radial symmetry
- …
Comments
No comments have yet been made