### animal | worm:

Flatworm
* All flatworms are acoelomate, triploblastic and bilaterally symmetrical.
* Every Flatworm can mate with any other Flatworm if it is the same species.
* Many flatworms produce both male and female reproductive cells and can fertilize their own eggs
  - reproduce asexually as well as sexually
* Most Flatworms are hermaphroditic, meaning they are both male and female
  - have at least two eyespots close to the head end of the body
  - flatworms absorb oxygen
* Most flatworms are carnivorous and feed on slow moving animals
  - live in films of water within the compost structure
  - parasitic, including important parasites of humans
  - can reproduce sexually or asexually
  - detect movement
* Most flatworms have bilateral symmetry
  - heads
  - hosts
  - mouths
  - multiple hosts
* Most flatworms live in digestive tracks
  - produce offspring
  - search for food
  - seek prey
* Most flatworms share common ancestors
  - many similarity
  - start life
  - survive periods
* Some Flatworms scavenge on dead and dying invertebrates
  - flatworms absorb nutrients
* Some flatworms are invertebrate animals with a distinct head and tail, and a primitive brain
  - avoid light
* Some flatworms cause deformities
  - diseases
  - human diseases
  - eat snails
* Some flatworms have ability
  - astound ability
  - cavities
  - cell layers
  - cuticles
  - hooks
  - patterns
  - pigment
  - sides
  - tiny tentacles over their heads
  - inhabit sediments
  - lay only a few eggs
* Some flatworms live freely, while others are parasites that live inside the bodies of other animals
  - in oceans
  - move through slime
  - parasitize snails
  - pose threats
* Some flatworms retain ancestral conditions
  - seek out mates
* Some flatworms undergo fission
  - transverse fission
  - use diffusion
  - wrap around the thicker spines of the diadema sea urchin.
  * are one of the invertebrate groups which are studied in school biology. The main reason for this is that they may infect humans, pets and farmyard animals, and this was a problem. Some do enormous harm to humans and their livestock. Schistosomiasis, caused by one genus of trematodes, is the second most devastating of all human diseases caused by parasites, surpassed only by malaria. Effective treatments are now available for these infections. Also, in first-world countries, regulations on domestic cattle prevent infected meat from reaching the human hosts
* adapt to any new host without causing a lot of harm to their hosts.
* also obtain oxygen by diffusion
  - reproduce sexually, but even that they do in their own interesting manner
* are a step behind the roundworms
  - able to fertilize themselves, which form an asexual reproduction
  - also very successful at regeneration
  - at the tissue-organ system level of organization
  - attractive to study because their regenerative abilities are quite pronounced
* are bilaterally symmetric
  - symmetrical invertebrates typically flattened in appearance
  - carnivorous heterotrophs
  - common organisms used in the science laboratory to describe asexual reproduction
  - complex animals with elaborate reproductive systems
* are dorso-ventrally flattened to varying degrees and elongate, with soft body tissues
  - flat and soft as jelly
  - flat, roundworms are round
* are found in marine and fresh water
  - marine, freshwater, and even damp terrestrial environments
  - many places and can be free living or parasitic
  - on the soil surface
  - good study subjects because their regenerative abilities are quite pronounced
* are hermaphrodites and have both male and female sexual reproductive organs
  - that can self-fertilise
  - hermaphrodites, so each individual possesses both male and female sex organs
* are in the phylum
  - their own phylum
  - mainly detritivores and are always present to some degree in a reef aquarium
* are major predators of adult barnacles
  - barnacles, bryozoans and oyster spat
  - mostly parasites and cause many diseases
  - much more complex that sponges or jellyfish and more animal-like
* are simple animals with few specialized structures
  - invertebrates with flat bodies
  - worms that are bilaterally symmetrical in shape
* are the first organism to show bilateral symmetry
  - least complex worms
* are the simplest animals with a. a backbone
  - of the worm groups
  - triploblastic animals with organs
  - thin flat and oval
  - unsegmented worms belonging to the Phylum Platyhelminthes
  - unsegmented, whereas annelids are segmented
  - very simple organisms and lack respiratory or circulatory systems
* battle one another with their penises.
* can be parasitic or free-living
  - contain powerful toxins
  - get around
* come in many shapes and sizes.
* consume materials
  - plant materials
* crawl over damp areas in search for their food.
* divide in two, then each half regenerates into a new flatworm identical to the original.
* exhibit two forms of life styles, free-living and parasitic.
* get most of their oxygen through diffusion.
* have a head at one end with two eye spots
  - nervous, digestive and reproductive systems
  - respiratory system
* have bilateral symmetry and they are the first animal group with a head
* have both male and female reproductive body parts
  - brains
  - flat, symmetrical, leaf-shaped bodies that grow to a size smaller than a quarter
  - larvae that have cilia that they use for feeding and locomotion
  - protonephridia are blind tubes that only open to outside
  - their digestive cavity in a bilaterally symmetrical body
  - very simple nervous systems
* includes brains
  - cell membranes
  - corpi
  - cytoplasm
  - ears
  - faces
  - flame cells
  - nuclei
  - plasma membranes
  - sections
  - skulls
  - vacuoles
* is the common name for members of the scientific phylum Platyhelminthes.
* like to hang onto surfaces.
* live in a variety of marine, freshwater, and terrestrial habitats worldwide
  - water or environments with high moisture
* move about using cilia and by undulating movements of the whole body.
* occupy a broad range of habitats in salt water, fresh water and wetlands.
* range in length from less than one millimeter to several meters long.
* reproduce as hermaphrodites
  - sexually and disperse via eggs
* seem to be reported in more and more instances as a major pest of corals.
* serve an important role in the marine ecosystem.
* share ancestors
  - several features with more derived animal phyla
* spend most of their time searching for food.
* tend to be much flatter and thinner, and can move faster than nudibranchs.
* to adapt to aquatic life
* typically perform sexual reproduction and are hermaphroditic.
* usually live in water, hiding under rocks or debris.