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Planaria whole mount (no high power) shows the main features of the body; one individual has been fed particles of carbon, and these blacken the gastrovascular cavity. It is highly branched, because it serves also for circulation of nutrients to every cell.
- What type of digestion do planarians have?
- Why do Planaria have ladder like organs?
- Does the planarian have a complete or incomplete digestive system?
- How does Planaria body shape assist with gas exchange?
- Why do you think the Planaria gut is so branched and spread out in this animal?
- Why is the gastrovascular cavity branched in planaria?
- How do Planaria move?
- Why do Planaria move away from light?
- Are Planaria segmented?
- Why are Planaria considered more advanced than cnidarians?
- What type of digestive system does a flatworm have?
- Why is the digestive tract of flatworms called incomplete?
- How do Planaria exchange gases?
- How does the shape of a flatworms body allow it to rely on diffusion for its respiration and excretion?
- What process do Planaria exchange gases with the environment?
What type of digestion do planarians have?
Once a planarian has sensed food, moved to it, and ingested it, the food is digested by both extracellular digestion and intracellular digestion. The lining of the gastrovascular cavity (the gastrodermis) releases digestive enzymes into the GVC. The ingested food is broken down to small food particles by this process.
Why do Planaria have ladder like organs?
They can reproduce asexually simply by pinching in half; each half grows a new half. Scientists say planaria have ladder like organs. Why? It consists of a brain and nerve cords arranged in a ladder-like configuration.
Does the planarian have a complete or incomplete digestive system?
Figure 1: This planarian is a free-living flatworm that has an incomplete digestive system, an excretory system with a network of tubules throughout the body, and a nervous system made up of nerve cords running the length of the body with a concentration of nerves and photosensory and chemosensory cells at the anterior ...
How does Planaria body shape assist with gas exchange?
Platyhelminthes exchange gases exclusively by diffusion through their body surface. This is only possible because all cells are located relatively near their exterior, since gases diffuse cell by cell (the flat shape of these worms is a feature that allows this type of respiration).
Why do you think the Planaria gut is so branched and spread out in this animal?
The extended branching of the digestive system allows for more space for monomers, and therefore nutrients, to be drawn into more of the animal's tissue. The function of the digestive system is also tied to the interaction between the planarian's skin and the surrounding environment.
Why is the gastrovascular cavity branched in planaria?
Planaria whole mount (no high power) shows the main features of the body; one individual has been fed particles of carbon, and these blacken the gastrovascular cavity. It is highly branched, because it serves also for circulation of nutrients to every cell.
How do Planaria move?
Some planarians move by beating cilia (protuberances of epithelial cells), which allows them to glide. Others move by contracting muscles and undulating their bodies.
Why do Planaria move away from light?
Though they possess a highly simplified anatomy, planarians still exhibit certain complex behaviors. For one, planarians reveal a negative phototaxis behavioral response, meaning that they evade light (Inoue et al, 2004), and this response may be the result of a variety of factors.
Are Planaria segmented?
Planarians are flat, soft-bodied worms with a triploblastic body plan and lacking visible segmentation.
Why are Planaria considered more advanced than cnidarians?
Why are planarians considered more complex then sponges and cnidarians? they are active hunters, they have a brain. ... All arthropods have an exoskeleton, segmented bodies, jointed limbs, and a well developed brain.
What type of digestive system does a flatworm have?
Like the cnidarians, flatworms have a digestive system with only a single opening into the digestive cavity, but in independently living marine flatworms the cavity branches into all parts of the body (Fig. 3.37 B). These flatworms feed through a pharynx.
Why is the digestive tract of flatworms called incomplete?
Due to the lack of a body cavity, flatworms are known as acoelomates. Flatworms have an incomplete digestive system. This means that the digestive tract has only one opening. ... Their gastrovascular cavity helps distribute nutrients throughout the body.
How do Planaria exchange gases?
They go through cellular respiration by oxygen entering and carbon dioxide leaving the body through diffusion through the body wall.
How does the shape of a flatworms body allow it to rely on diffusion for its respiration and excretion?
how does the shape of faltworms body allow it to rely on diffusion for its respiration and excertion? they are flat which allows more things to enter and exit.
What process do Planaria exchange gases with the environment?
Direct Diffusion
In simple organisms, such as cnidarians and flatworms, every cell in the body is close to the external environment. Their cells are kept moist so that gases diffuse quickly via direct diffusion. Flatworms are small, literally flat worms, which 'breathe' through diffusion across the outer membrane.
