Biology- Urchin Anatomy, pH, Ocean Acidification
How much of the Earth is covered in oceans?
2/3
What pH should ocean water be?
8
What is the digestive system?
Along with the five gonads, the digestive tract takes up most of the internal space of the sea urchin which is important because the circulatory system needs nutrients from it. Waste is expelled through the anus located at the top of the body.
What happens to sea urchin shells when ocean acidification occurs?
The CO2 increases in the water and creates carbonic acid. This carbonic acid breaks down into bicarbonate and carbonate, releasing hydrogen ions, decreasing the pH. The carbonic acid is shifted towards bicarbonate due to the excess hydrogen. With less carbonate, less calcium carbonate can be formed, which can cause weaker shells and slower growth for the urchin.
Is pH increasing or decreasing in oceans?
decreasing; they are becoming more acidic
what does pH actually measure?
hydrogen ion concentration
Is atmospheric CO2 increasing or decreasing?
increasing
What happens to the CaCo3 as the atmospheric gets higher?
it drops
How does acidification affect invertebrate animals like corals?
it increases the amount of carbon dioxide, decreasing the amount of available calcium carbonate
What happens to the H2CO3 (carbonic acid) as the atmospheric gets higher?
it rises
What happens to the HCO3 (bicarbonate) as the atmospheric gets higher?
it rises
What happens to the ocean CO2 as the atmospheric gets higher?
it rises
Where do our bodies lie on the pH scale?
neutral- 7/8
What is the nerve ring?
sea urchins have no "brain," instead they have a nerve ring that powers their tube feet.
where in our bodies is there a very low pH?
stomach
What is Aristotle's lantern?
the mouthparts of the sea urchin that consists of five boney plates used to scrape at the holdfast of kelp and their other food sources
what is the test?
the shell of the sea urchin, that is mainly comprised of calcium carbonate
What are spines and pedicellaria?
the spines are the urchin's primary mode of defense against hungry predators. the spines are used by some species to burrow into rock by slowly scraping away an enclosure to further protect themselves. the spines are controlled by two rings of muscles and are covered with a layer of epithelium. at the base of the sea urchin's spines are pedicellaria which are small pinching appendages.
What is the water vascular system?
the system responsible for circulation, as well as the motor movement in echinoderms by pressuring the tube feet.
what are tube feet?
the tube feet are the primary means of locomotion for the sea urchin. lateral movement is accomplished by means of paired muscles in the tube foot itself and extension and retraction by muscles in the hydraulic bulb behind each tube foot. while each foot may seem weak and ineffective, the large numbers of feet make up for their size.
What are gonads?
the urchin's reproductive organs. most urchins reproduce through spawning, meaning the males expel the sperm and the females expel the eggs into the water
