Kingdom Animalia Flashcards
(14 cards)
Structure of Animals
Multicellular, composed of eukaryotic cells lacking cell walls and chloroplasts
Heterotrophs - feeding on other orgs and digesting in a gut cavity - enteron
most move place to place in search for food
Phylum Cnidaria
Aquatic
•Radially symmetrical body - respond to environment through 360°
•Enteron sac-like, only one entrance (mouth)
•Tentacles contain ‘ stinging cells’ used to catch food - conveyed by tentacles to mouth
•Body supported by surrounding aqueous medium and a hydrostatic skeleton formed by fluid filled enteron
•movement limited - jellyfish ocean currents, Hydra cartwheel though sedentary
Phylum Platyhelminthes
Commonly called flatworms
Planarians - fresh and salt water and most soil
Liver Fluke - in animal tissue
Radially Symmetrical
body parts arranged in a circle around an imaginary line through mouth and gut
Bilaterally Symmetrical
body parts arranged on either side of an imaginary line through their mouth and gut cavity
Body of a Planarian
-Bilaterally symmetrical body - can move forward
-movement in one direction means that a front end evolves as well as a specialised ventral surface w/ a distinct dorsal surface
-most detritivores but there are a few active carnivores
-dorso-ventrally flattened - large SA to vol ratio
-gut has only single opening though is highly branched , permeating all parts of the body
-no cell far from either gut or body surface - short diffusion path for metabolites - no circulatory system
-body supported by aqueous medium - though well packed cells in body provide supportive role - soft bodied and no specialised skeletal system
Phylum Annelida
Segmented worms including earthworm and lugworm
Inhabit aquatic and moist terrestrial ecosystems
Body of an Earthworm
•bilaterally symmetrical - round in transverse section
•through (one-way) gut - mouth and anus - detritivores
•gut allows regional specialisation
•gas exchange over moist body surface - blood circulatory system required for distribution gases and food molecules
•metamerically segmented
•supported by a hydrostatic skeleton provided by segmented fluid filled cavities
•locomotion relies on muscle acting on hydrostatic skeleton - aided by external bristles of chitin - chaetae
•long and thin for ease of movement
Regional Specialisation
Food drawn into a muscular pharynx, passed along an oesophagus to be stored in the crop
Slowly released into muscular gizzard where it is crushed - digested and absorbed in intestine
Allows ingestion of food to continue, while previously invested food is digested
Phylum Arthropoda
Arthropods live in a wide variety of habitats - both aquatic and terrestrial, incl air
3/4 all animal species are arthropods - insects alone account for more than half total
Body of an insect
•bilaterally symmetrical
•one way gut allowing regional specialisation
•metemerically segmented - diff regions with a fixed number of segments in each region
-insects: head(6) thorax(3) and abdomen(11)
•rigid exoskeleton of chitin - protection, water retention and support
•muscles governing mvmnt attached internally to exoskeleton of the jointed limbs and to wings for flight
•exoskeleton limits size - needs to be shed prior growth spurt - creates need for specialised gas exchange surfaces
•exoskeleton covered in waxy water-resistant cuticle - further reduce desiccation - crustaceans lack this
Phylum Chordata
Chordates include the vertebrates
Fish, Amphibians, Reptiles, Birds and Mammals
Body of mammal
•bilaterally symmetrical - metamerically segmented and possess one way gut
•vertebral (spinal) column
•endoskeleton consists of an internal jointed system of calcified bones - muscles for locomotion attach externally
Evolutionary Trends in Kingdom Animalia
•from radial symmetry (sedentary) to bilateral symmetry (consequence directional movement)
•from sac like gut cavity(enteron) to a through gut
•towards the dev of an internal blood transport system - inclusion of rigid skeleton and possession of an impermeable outer covering - better adapted to terrestrial existence
