Biology Ch. 26-28 Worms and Mollusks Quiz(AT) Flashcards
Flatworms are the simplest animals that have what five things?
- They have soft, flattened bodies.
- They have tissues and internal organ systems.
- As embryos, they have three germ layers.
- They have bilateral symmetry.
- They show cephalization. (They have a ‘head’.)
Why are flatworms called acoelomates?
They do not have a true coelom. Their only body cavity is the digestive cavity.
_______ is a fluid filled body cavity derived from the mesoderm.
Coelom
How is the digestive process different in free-living flat worms compared to parasitic flatworms?
Free-living flat worms can be carnivores or scavengers while parasitic flatworms must have a host.
Name the biological systems that take advantage of diffusion in flatworms.
Respiration, circulation, digestion, and excretion.
_______ is a specialized cell used to eliminate excess water and wastes from free-living flatworms.
Flame cell
_______ is a group of nerve cells that control the nervous system in free-living flatworms.
Ganglia
______ is a group of cells that detect light changes.
Eyespot
What are two ways flatworms move?
Cilia and muscles (twist and turn)
How does reproduction differ between free-living flatworms and parasitic flat worms?
Free-living flatworms do not need a host to reproduce.
_________ is the only group of free-living flatworms.
Turbullerians
_______ mostly infect internal organs of host organisms but they can also infect the skin, mouth, gills, etc.
Flukes
_________ are typically the longer worms found in the host’s intestine.
Tapeworms
________ contains suckers and hooks to attach to the host’s intestinal wall.
Scolex
________ are segments that make up most of the body and contain both the male and female reproductive organs.
Proglottids
Describe what a round worm looks like?
Slender and non-segmented
Where are they found?
Infected meat, water, and soil
In round worms, food passage is in _________ direction.
one
Roundworms depend on _________ to carry nutrients and wastes through their bodies.
diffusion
What does their nervous system consist of?
Ganglia
Round worms’ hydrostatic skeleton consists of _________ and fluid within the ________.
muscles, pseudocoelom
Are round worms hermaphroditic?
No
Describe any human diseases caused by roundworms that were discussed in class.
- Trichinosis - eating undercooked meat.
- Filarial worms - block the lymph vessel causing extreme swelling.
- Ascarid worms - eating vegetables and fruit that aren’t washed thoroughly and food not cooked thoroughly.
- Hookworms - get them from walking around barefoot.
Annelids are believed to be more closely related to ________ because they have similar larval stages.
snails and clams
_______ are internal walls between each of the body segments of segmented worms.
Septa
Annelids are the only worms to have a true _______.
coelom
Annelids have a ________ digestive system in which food passes in one direction.
complete
Although annelids obtain nutrients in a variety of ways, food always enter through the _________.
pharynx
________ is the hollow tube that food travel to get from the pharynx to the crop.
Esophagus
________ is the internal organ used to store food during digestion.
Crop
________ is the internal organ used to grind food during digestion.
Gizzard
_________ is the internal organ used to absorb the nutrients during digestion.
Intestine
Annelids have a ________ circulatory system.
closed
Aquatic annelids use _________ for respiration while land dwelling use __________.
gills, moist skin
_________ filter out cellular wastes.
Nephridia
Annelids are the only worms to have a definite ________ used for response.
brain
________ muscles makes the worm shorter and fatter while ________ muscles make the worm longer and thinner.
Longitudinal, circular
________ are structure used to prevent slipping during movement.
Setae
_________ is a band of thickened specialized segments that secretes a mucus ring into which eggs and sperm are released for fertilization.
Clitellum
Describe the three groups of annelids.
- Oligochaetes - These worms have a streamlined body, live in dirt or fresh-water and have very few setae.
- Leeches - external parasite.
- Polychaetes - marine annelids with paired appendages with setae.
Describe the ecological importance of annelids.
- The tunnels they make in the ground provide passageways for plant roots and water to get through soil.
- They help aerobic bacteria to live underground.
- They bring digested plant material to bacteria for decomposition.
- They bring up minerals from deeper layers of soil.
- Provide food for many terrestrial and marine carnivores.
Mollusks are ________ bodied that usually have some sort of __________.
soft, shell
All mollusks have four parts. List and describe each.
- Foot-used for crawling, burrowing, and/or capturing prey.
- Shell-made of calcium carbonate and used for protection/structure.
- Mantle-thin layer of tissue covering the body.
- Visceral mass-all the internal organs.
___________ is a tongue-like structure used to obtain food.
Radula
Aquatic mollusks have _________ for the respiration while the land dwellings use their _______ cavity.
gilla, mantle
_________ circulatory system is one which blood is pumped through the body openly.
Open
________ circulatory system is one where blood is closed in and returns to the heart by specific vessels such as arteries.
Closed
__________ removes ammonia from the blood and releases it outside the body.
Nephridia
__________ is a structure that sucks in water and excretes excess water.
Siphon
Which group of mollusks shows the most developed response system?
Cephalopods
What are the three groups of mollusks and how do they differ.
- Gastropods: shell-less or single-shelled and move with a foot on their belly(slugs and snails). Can hide in their shells.
- Bivalves: have two shells held together by powerful muscles. Spend most of their time in one place and filter feed. Clams and oysters are examples.
- Cephalopods: soft-bodied mollusks that consist of a head attached to a foot that is divided into several tentacles. Examples are octopi, nautiluses, squids, and cuttle fish.
