Intro to Animal diversity, form and function, and homeostasis

Question 1

What are the defining characteristics of animals?

Answer 1

animals are multicellular heterotrophs that feed by ingestion, have extra cellular matrix’s and collagen, a blastula stage of development, hox genes, distinct germ layers, symmetry, muscles, nervous system, and senses.

Question 2

Would you consider a sponge to be an animal, explain. Be sure to include a description of the
characters of both sponges and animals in your explanation.

Answer 2

I would consider a sponge not to be an animal. Sponges are more like sisters to animals, because they lack key characteristics, such as germ layers, symmetry, muscles, and a nervous system. These are all very important defining characteristics of animals. The argument that they are animals is based in the characteristics sponges share with animals, including differentiated cell types, apoptosis, collagen, recognition of cell from no self, regulation of the cell cycle and growth, gene regulation, and developed signaling. However, their lack of the other defining characteristics clearly distinguishes them apart from animals.

Question 3

Explain why cnidarians do not require a circulatory system

Answer 3

Cnidarians have a thin body wall and a large surface area so that it can easily diffuse oxygen directly from their surroundings. There is no need for a circulatory system.

Question 4

List the defining characters of Cnidarians

Answer 4

Cnidarians have radial symmetry, two germ layers, stinging tentacles with cnidocytes, and there are 4 main lineages (hydrozoans, cubazoans, scyphozoans, and anthrozoans)

Question 5

List the defining characters of arthropods

Answer 5

Arthropods have a hard exoskeleton made of chitin, jointed limbs, and compound eyes

Question 6

List the defining characters of mollusks

Answer 6

mollusks have a mantle used for excretion and breathing, and have radula (except bivalves)

Question 7

List the defining characters of chordates

Answer 7

chordates include animals with backbones, a muscular post-anal tail, pharyngeal slits/ gills in fish, dorsal nerve cord, notochord

Question 8

What’s the average body temperature of humans?

Answer 8

around 98 degrees F
97.7-99.6F

Question 9

Define homeostasis

Answer 9

homeostasis is maintaining an internal balance, or an ordered, nearly-constant internal environment different from one’s surroundings
(an organisms ability to resist change and maintain its set points, or the relatively constant internal environment)

Question 10

Explain why there are no perfectly adapted animals (include a trade-offs and provide examples)

Answer 10

There are no perfectly adapted animals because there are always trade-offs to adaptations. For example, many animals such as birds and fish trade off speed for agility, and vice versa. Jumping spiders have large forward-facing eyes for hunting, where web-spinning spiders have smaller eyes because they don’t have to actively hunt when their web catches their prey.

Question 11

What’s the difference between acclimation and adaptation, explain why you cannot adapt to
your environment. (provide examples)

Answer 11

adaptation is a long term adjustment that occurs over generations in a population as a result of genetic changes due to environmental factors. Acclimation is a short-term, more immediate change on an individual level to environmental changes and is dependent on the genetics of an organism (like the production of melanin)

Question 12

Name the four types of tissues in the human body

Answer 12

Connective, epithelial, muscle, and nervous tissue

Question 13

Which types of tissues have excitable membranes?

Answer 13

Nervous and muscle tissues have excitable membranes

Question 14

Animals living in cold water face several challenges: How could they maintain membrane fluidity in cold temperatures? Explain

Answer 14

An animal living in cold water could maintain membrane fluidity by having short, unsaturated fatty acids. This would allow for more membrane fluidity than long, saturated fatty acids because they are less viscous and more susceptible to changes in kinetic energy. The short, poly unsaturated fatty acids would allow the membrane to be more fluid and not solidify due to the bends/kinks in the membrane

Question 15

Animals living in cold water face several challenges: What would happen if their membranes became too viscous or rigid?

Answer 15

If the membrane became too viscous or rigid, this would impact cell function and risk cell death?

Question 16

how is special fluid connective tissue different from the other types of connective tissue?

Answer 16

Special fluid connective tissue (=blood cells) do not contain fiber and transport materials including oxygen throughout the body and play an important part in our immune system.
Other connective tissues do not transport fluid and are generally used for structural support (like dense connective tissue = tendons and ligaments that attach muscles to bones and connect bones together) (bones = connective tissue)

Question 17

In class I described bilateral animals as a “tube”, What did I mean by that (Hint: The digestive
tract)

Answer 17

Bilateral animals are just a tube as in their digestive tract functions ultimately as one long tube that travels through the Boyd and connects the mouth to the anus

Question 18

Define metabolism

Answer 18

the sum of all chemical reactions in an organism

Question 19

Define metabolic rate

Answer 19

the overall rate of energy consumption by an individual

Question 20

Determine base metabolic rate

Answer 20

The rate at which an animal consumes oxygen while at rest

Question 21

Explain why an elephant has a higher whole-animal metabolic rate than a shrew, but a shrew has a much higher mass-specific metabolic rate

Answer 21

An elephant has a much larger mass than shrew, and therefore will have a higher whole-animal metabolic rate than a shrew because it has a much larger body and therefore consumes more energy. However, a shrew has a higher mass-specific metabolic rate because when compared to the elephant on an even scale, the shrew has a higher MR per gram. Smaller animals lose more heat (larger surface area to total volume ratio), and therefore require more energy and consume nearly their body weight in a day (where an elephant comes only a fraction of their weight) to maintain their body temp

Question 22

Based on the laws of thermodynamics, are animals open or closed systems?

Answer 22

Animals would be considered open systems because they exchange energy with their surroundings by consuming and releasing energy by doing work. This follows the laws of thermodynamics because E cannot be created nor destroyed and as it is transferred and used is loses some of its usability (giving off heat, poop, nitrogenous waste)

Question 23

If energy cannot be created nor destroyed, then can Animals recycle energy? Explain using the laws of thermodynamics

Answer 23

Animals do not necessarily recycle energy, however energy does transform and is transferred throughout the body so animals can do work. By the definition of the second law of thermodynamics, as this energy is used (transferred or transformed), it becomes less usable as entropy increases (meaning it is not being recycled within its self, but absorbing more energy from food in order to gain the E it needs)

Question 24

Where did the energy in your body ultimately come from?

Answer 24

The sun

Question 25

Why are hummingbirds about as small as an endotherm can get?

Answer 25

Endotherms have to be able to regulate their internal body temperature, and the smaller the animal, the larger the surface area to total volume ratio is. This means that they are loosing more heat to their surroundings as most of their body is in direct contact with it. Anything smaller than a hummingbird would lose heat too rapidly to maintain it.

Question 26

How is metabolic rate measured? Explain why? (hint: cellular respiration)

Answer 26

Metabolic rate can be measured through the processes of cellular respiration, including rate of O2 consumption, and rate of CO2 released, as well as other techniques such as calorimetry to see how much heat energy is being released from an animal.

Question 27

When it comes to maintaining homeostasis, what are set points? provide examples

Answer 27

Set points are physiological values at which an animal is best able to maintain a relatively constant internal environment. For example, in humans these values are around 98 degress body temp, 7.4 pH of blood, and 7-10mg glucose/L.

Question 28

Explain the role of negative feedback in maintaining homeostasis

Answer 28

Homeostasis used negative feedback to maintain set points (often through two negative feedback loops that maintain electrolytes and blood sugar levels)

Question 29

If it’s hot outside, how do sensors, integrator, and effectors work together to keep you cool by sweating?

Answer 29

When it’s hot outside, sensors will sense variables in the external environment and signals the hypothalamus in the brain, the integrator, which evaluates the information compared to our set points. It then determines the appropriate response (to cool the body down), and signals effectors (such as sweat glands) to activate mechanisms to reduce heat (sweat and dilates blood vessels) and maintain an internal temp around 98F

Question 30

what happens if an animal cannot maintain homeostasis?

Answer 30

It dies. If an animal reaches temperatures that are too hot or too cold, their enzymes stop functioning efficiently or denature all together, making it impossible to do work and the animal dies

Question 31

Why are pH and temperature important in maintaining homeostasis.

Answer 31

the pH is very important because each protein has an optimal pH environment, and in the wrong conditions the enzymes will cease to function properly (or at all) (ex. enzyme from stomach would not work in the intestines). Temperature has a similar importance in maintaining homeostasis as enzymes will operate too slowly at cold temperatures and can denature at hot temperatures (relative to the organism’s set points)

Question 32

Define the four methods of heat exchange.

Answer 32

Conduction- direct transfer of heat through touch
convection- heat exchange between solid and moving liquid or gas
radiation- transfer of heat between bodies not touching
evaporation- causes heat loss from phase change of water to gas

Question 33

Why does evaporation always lead to heat loss?

Answer 33

the process of water changing to gas requires an input of heat energy and the molecules take away this energy in order to phase change, causing a cooling of the liquid that is left

Question 34

Why should you not use the term “cold blooded” when describing ectotherms like lizards in New Mexico

Answer 34

Cold blooded implies that these animals have cold blood, which is not the case. It is better to use the term ectotherm, because what the animals are actually doing is relying on heat from their environment to maintain their internal body temperature.

Question 35

How do endotherms generate body heat?

Answer 35

Endotherms generate body heat through their metabolism

Question 36

What is a homeothermic ectotherm? Where might you find one?

Answer 36

A homeothermic ectotherm is an animal that keeps their body temperature constant while also using relying on heat from their surroundings to do so (meaning their environment would have to be nearly constant all the time–> like an angler fish and in the deep sea where the temp in constant)

Question 37

Why are some species of hummingbirds Poikilothermic (heterothermic)

Answer 37

poikilothermic or heterothermic refers to an animal whose body temperature varies wildly. Some species of hummingbirds are heterothermic because they rapidly lose heat due to their large surface area to volume ratio. They survive this way by dropping their body temps at night to conserve energy (torpor).

Question 38

Describe the evolutionary trade-offs between ectothermy and endothermy.

Answer 38

Ectotherms require less energy in the form of food, as they use their environment and diffusion to regulate internal temperature. However, in extreme climates outside of their set points, they are not able to adapt as well and are therefore limited to specific environments. They also cannot be active at all times of the day.
Endotherms require energy through food in order for their metabolism to function and maintain their internal body temp despite their surroundings. This allows them to adapt more to extreme environments, and be active throughout the day, however they are dependent upon having access to food sources, and there are limits to how much they can regulate temperature before the animal freezes, or overheats to death

Question 39

Explain the trade-offs for the three different types of nitrogenous waste excreted by animals

Answer 39

Uric acid, urea, and ammonia are three different types of nitogenous waste excreted by animals. Uric acid has very low solubility, water loss, and toxicity, but a high energy cost. Urea has medium solubitlity, water loss, and toxicity, but a high energy cost as well. Finally, ammonia has high solubility, water loss, and toxicity, but a low energy cost.

Question 40

Explain the difference between isosmotic, hyperosmotic, hypoosmotic.

Answer 40

iso = same osmotic pressure as surrounding/something else
hyper= more osmotic pressure than surroundings/ something else
hypo = less

Question 41

Explain how a shark can be isosmotic, but out of equilibrium with sea water.

Answer 41

A shark is isosmotic with their environment due to the presence of urea, keeping their osmolarity and water potential the same as their environment, but they are out of equilibrium with sea water due to the differences in electrolyte concentrations. They actively pump out sodium and use urea concentrations to stay isosmotic with their environment

Question 42

Compare and contrast how freshwater and marine bony fish maintain osmotic balance.

Answer 42

Marine fish maintain osmotic balance by maintaining high concentrations of urea !!!!FIX THIS ONE!!!!

Question 43

Know what Chondrichthyes and Osteichthyes are.

Answer 43

Chondrichthyes - cartilaginous fish that are osmocomformers
Osteichthyes - bony fish that are osmoregulators

Question 44

Explain how sharks excrete salt (diagrams are helpful).

Answer 44

Sharks excrete salt through their rectal glands. In the epithelial cells of these glands, a sodium potassium pump in the basolateral membrane pumps Na+ ions out into the extracellular fluid and pumps K+ ions into the cells. This creates an electrochemical gradient that stores potential energy to do work. The Na+ ions are then out of equilibrium with the cells and want to go back in, so the stored potential energy allows the Na+, K+, Cl- cotransporter to pump Na+, which drags with it K+ and Cl- ions, back into the cell. The increase concentration of Cl- and K+ions allow them to be pumped back out of the cell (K+ into the extracellular fluid and Cl- into the lumen of the gland) through facilitated diffusion. Finally, the Na+ ions diffuse into the lumen thru the epithelial cells, allowing the shark to excrete salt through their rectal glands

Question 45

Know what the Malpighian tubules are used for.

Answer 45

Work as the kidneys for arthropods to remove nitrogenous waste
K+ is pumped into tubules, brings in water and other electrolytes, and excretes nitrogenous waste (uric acid).

Question 46

Why would a terrestrial vertebrate and a marine fish both risk water loss?

Answer 46

The terrestrial vertebrate risk water loss through evaporation, which helps them osmoregulate.
Water potential is lower in sea water so marine fish are going to lose water through diffusion across their gills

Question 47

If you were stranded at sea, why couldn’t you drink the sea water

Answer 47

Sea water has a high salt concentration, meaning that drinking sea water would force our bodies to take in more salt than it can process. This pulls water out of our cells as osmotic regulation works to dilute the seawater, but at such high concentrations, the cells would ultimately shrivel up and die

Question 48

Explain how a nephron filters the blood and reabsorbs water, electrolytes, and nutrients.
—>Cover what happens in each of the four main parts of the nephron

Answer 48

The nephron is the basic functional unit of a kidney. It has four main regions: the renal corpuscle, proximal tubule, loop of Henle, and distal tubule. The renal corpuscle filters blood creating a filtrate with ions, nutrients, waste, and water. The proximal tubule is where epithelial cells reabsorb nutrients, ions, and water from the filtrate back into the blood. The loop of Henle establishes a strong osmotic gradient in the interstitial fluid. Osmolarity increases lower into the medula.

Question 49

Explain cooperative binding in hemoglobin

Answer 49

Cooperative binding describes how each binding of oxygen to hemoglobin makes it easier for the next oxygen to bind
AND each loss of bound oxygen makes it easier for the next oxygen to leave
Not linear relationship

Question 50

Explain how carbon dioxide is transported in the blood

Answer 50

CO2 in mostly transferred in the blood as mostly bicarbonate because carbonic anhydrase coverts CO2 and water into carbonic acid (which then converts into bicarbonate as activity increases and pH drops)
This creates a pressure gradient of CO2 that favors diffusion to the atmosphere

Question 51

Explain the Bhor Shift as it relates to oxygen transport

Answer 51

Hemoglobin is very sensitive to ph due to cooperative binding
—> the Bhor shift refers to the decrease in pH during exercise causing more O2 to be unloaded (carbon dioxide increases in blood and decreases pH a tiny bit —>causes oxygen to unload)

Question 52

Explain the importance of a four chambered heart for mammals and birds (include the importance of double circulation)

Answer 52

Mammals and birds are endotherms and require more O2 than ectotherms —> four chambered heart =double circulation and allows for oxygen rich blood and oxygen poor blood to be pumped separately from the pulmonary route and the systemic route
= efficiently circulates oxygen rich blood throughout the body by controlling the blood being pumped through the two routes
(Left ventricle is much larger)

Blood is moved much faster due to higher pressure on systemic route, also allowing animal to be more active and grow larger

Question 53

Explain how terrestrial vertebrates with three-chambered hearts may not grow as large or be as active as mammals.

Answer 53

Terrestrial vertebrates with three chambered hearts have ventricles that pump blood into a forked artery. This results in the deoxygenated and oxygenated blood mixing, limiting the amount of energy and work these animals can do because it is less efficient in pumping oxygen rich blood throughout the body and they run out of energy more quickly, meaning they cannot grow as large or be as active as mammals with a more efficient four chambered heart

Question 54

Arteries vs. veins

Answer 54

Distinguished by direction of blood flow (not O2 content)
Arteries flow blood into capillaries
Veins flow blood out of capillaries

Question 55

Explain importance of evolution of closed circulatory system, three chambered heart, then four chambered heart in animals transition to land and growing larger