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Learning Check-List
Locust Ecological Niche
Discuss the ecological niche of locusts
Explain the ventilation and gas exchange in the locust tracheal system
Compare & contrast the advantages and limitations of this system
Tasks - Milestone #4
Engage with the videos and notes below. In your portfolio of learning complete the following tasks. It is important to paraphrase in your own words, and include the URL's and any other resources you used in your reference list. So that they are there ready for your final assessment.
1.Complete sciPAD pgs: 54-55
2.Summarise the ecological niche of locusts
3.List the ventilation structures in locusts and describe how they work
4.List the gas exchange structures in locusts and describe how they work. Pay special attention to the open-circulatory system of insects
5. Summarise the key advantages and limitations of this system
Taxonomy is the scientific study of naming, defining and classifying groups of biological organisms based on shared characteristics. Insects are an example of a taxonomic group, and locusts belong to this group.
Thinking back to your ecology learning, you will remember that an ecological niche is the functional position of a species in an ecosystem. You need to write about the ecological niche of locusts in your report and relate this back to the adaptations of the gas exchange system in locusts.
Watch this video to learn how the environment can change grasshoppers into locusts.
For more information to help you with the ecological niche of locusts visit this website.
Watch this initial video, created by a teacher in Auckland. It gives a fantastic overview of the insect tracheal system.
The next two videos below, are also valuable as overviews of the insect tracehal system.
The diagram above shows all of the key ventilation and gas exchange structures in a locust.
Insect Ventilation
Insect Ventilation
Locusts ventilate through a process called tracheal respiration, where they use a system of tracheae—tiny tubes that transport air directly to their cells. Here’s how the process works:
Air intake and expulsion: Locusts take in air through small openings called spiracles, located along the sides of their body. The spiracles open and close to regulate the amount of air coming in.
Tracheae and air sacs: Air travels through the spiracles into a network of tubes called tracheae, which branch into finer tubes called tracheoles. These tracheoles reach deep into the tissues to provide oxygen to cells and remove carbon dioxide.
Active ventilation: To increase air circulation, locusts use muscle contractions to actively pump air in and out of their tracheal system. This is important, especially when they are active, like during flight. The muscles in the abdomen contract and relax rhythmically, squeezing air sacs and forcing air to move.
Diffusion at rest: When at rest, gas exchange mainly occurs through diffusion, with air moving passively in and out of the tracheal system.
In summary, locusts use both passive diffusion and active pumping of air to ventilate their bodies, ensuring their cells get enough oxygen and expel carbon dioxide.
Caterpillar spiracles, clearly showing one per abdominal segment. key adaptations of insects GE systems.
INSECT GAS EXCHANGE - OVERVIEW
Key to the tracheal system is that insects have an open circulatory system (no heart, or blood vessels), the insects tissues are bathing in a blood like fluid known as haemolymph. The means that the oxygen is delivered directly to cells for cellular respiration. This is only possible because insects are small, larger animals like mammals and fish are larger so in order for oxygen to reach the extremeties of their bodies they need a closed blood system (heart and blood vessels).
Here’s a summary of how gas exchange occurs in locusts, after ventilation:
Gas diffusion: At the tips of the tracheoles, oxygen diffuses directly into the surrounding cells, where it is used in cellular respiration to produce energy. At the same time, carbon dioxide produced by the cells diffuses into the tracheoles to be expelled.
Expelling carbon dioxide: Carbon dioxide travels back through the tracheal system and is released out of the body through the spiracles during exhalation.
Ventilation mechanisms: While gas exchange is mainly passive through diffusion when the locust is at rest, during activities like flight, the locust actively ventilates its system by contracting abdominal muscles. This creates a pumping action that moves air more efficiently through the tracheae.
Locusts also have air sacs which play a crucial role in ventilation and enhancing gas exchange by acting as reservoirs for air and helping to move air more efficiently through the tracheal system. Here’s how they function:
Structure: Air sacs are thin-walled, expandable sacs connected to the tracheae. They do not have tracheoles, so they are not directly involved in gas exchange but aid in moving air throughout the system.
Ventilation: During periods of high activity, such as flight, locusts actively ventilate by contracting their abdominal muscles, which compresses the air sacs. This pumping action helps push air through the tracheae more effectively, bringing fresh oxygen to the tracheoles and removing carbon dioxide.
Increased airflow: The air sacs allow for larger volumes of air to be moved into the body with each breath, which is particularly important during intense activity when the locust's oxygen demand is higher.
Pressure regulation: By expanding and contracting, the air sacs help to regulate the pressure within the tracheal system, ensuring that air can flow efficiently even to deep tissues.
In summary, air sacs in locusts act as bellows that help ventilate the tracheal system, ensuring efficient airflow and supporting higher oxygen demand during activities like flight
ADAPTATIONS & LIMTATIONS OF LOCUSTS
Watch this video, although it is about crickets, it also applies to locusts.
Key adaptations to cover in your report should include spiracles, and how the abdomen ventilates air into the system, the open circulatory system of insects and importance of air sacs. Make sure you discuss how these adaptations support locusts with their metabolic demands and ensure their success in their ecological niche.
Focusing on the key features of an efficient GE system is important - see below.
Like the snapper and human systems, the tracheal system in a locust needs to make sure it has adaptations for efficient gas exchange, to be able to keep up with the high metabolic demands of this flying insect.
You need to research adn discuss in detail the daptations for how the system:
Maximises the SA : V (via tracheoles).
How the system ensures the preventing of damage to the tracheae and tracheoles.
How dessication is avoided and the system keeps tracheoles moist.
How the diffusion distance is minimised - e.g.: tracheoles(thin).
How the concentration gradient is maximised across tracheoles.
KEY LIMTATIONS OF THE LOCUST GAS EXCHANGE SYSTEM
Insects must be small (open circulatory system - relying on diffusion alone, chiten rings are heavy - too many of these in a bigger animal would make it hard to fly etc)
Incompatable with water (viscosity of water and the surface area to volume ratio of trachea is not large enough)
Tidal ventilation (oxygen enters through the spiracles, and carbon dioxide exits the same way - causing a mixing, lowering the concentration of oxygen reaching the tracheoles)
Dead space (not all of the air that enters the system, makes it to the gas exchange surface)
For lots more information visit this link..
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