Most reptiles also have a three-chambered heart like the amphibian heart. Reptiles have a muscular septum that when the ventricle contracts, separating the 2 chambers for a split second (Kimball 2010). Some reptiles (alligators and crocodiles) are the most primitive animals to exhibit a four-chambered heart. In mammals and birds, the heart is also divided into four chambers: two atria and two ventricles. The oxygenated blood is separated from the deoxygenated blood, which improves the efficiency of double circulation. The four-chambered heart of birds and mammals evolved independently from a three-chambered heart. (Overview of the Circulatory System 2013)
All vertebrate animals have kidneys, like that of humans. The primary nitrogenous waste filtered by the mammalian kidney is urea. Humans do not have the most efficient kidney in the within the mammalian class. The kidney in the kangaroo rat must be much more efficient because kangaroo rats do not have the luxury of running water, and must be extremely efficient with their water intake/loss to ensure their survival because of the dry environment they live in.(Renadyl.com 2018)
Evolutionarily, mammals inherited their kidney traits before the evolution of diapsids (reptiles and birds) whose kidneys can convert nitrogenous waste into uric acid. Many reptiles live in arid environments, so to cope with their surroundings they have evolved very efficient kidneys. Animals that live on dry land must continually drink water, as they do not get enough from the air to complete basic metabolic processes. Freshwater vertebrates, on the other hand, face the problem of too much water in their body. In order to maintain homeostasis (metabolic balance) of the extracellular fluid, they are constantly excreting excess water. (Ramsay & Kelley 2014)
Sound waves are detected through tiny hairs. Each of these hairs is connected to an individual nerve so, when vibrated, the brain receives an electrical pulse from that individual hair. Each hair is set at a certain distance and length, so each individual hair reacts differently to the next. The brain then cleverly processes all these electrical pulse combinations to find the corresponding pitches and frequencies and allows you to hear the resulting sound. (How Soundwaves Transduced in the Inner Ear 2018)
The steps as the ear processes sound to the brain:
1. First, the outer ear captures the sound.
2. Then sound passes through ear canal to cochlea, this is where the transduction of sound into neural signal happens.
3. When the neural signal is created, it then has to be processed. Firstly, the signal goes to the cochlear where the signal maintains tonotopic organization.
4. The signal then goes to the superior olivary nucleus, where all basic information and loudness differences are processed.
5. Lastly, the signal than goes to Inferior colliculus, where an auditory map of sound is created and can be integrated with motor movements to react to stimulus.
How Soundwaves Transduced in the Inner Ear 2018, Answers, viewed May 2018, .
Kimball, JW 2010, Animal Hearts, viewed May 2018, .
Overview of the Circulatory System 2013, Boundless.com, viewed May 2018, .
Ramsay, JA & Kelley, FC 2014, Excretion, Encyclopædia Britannica, inc, June 04, 2014, .
Renadyl.com 2018, The evolution of the Kidney in vertebrates, viewed May 2018, .
SJCROSS91 2011, Animal Biology Chapter 10, Quizlet, viewed May 2018, .