EXAM 4 LO

Define sexual and asexual reproduction.

• Sexual Reproduction: Fusion of haploid gametes (egg, sperm) into a diploid zygote

• Asexual Reproduction: Cloning of an organism, no genetic recombination

• All animals reproduce sexually just some reproduce asexually!

Explore different modes of asexual reproduction.

• Budding: Fragmentation of parts from an original organism developing into new individuals

  • Ex. Corals, Hydras

• (Binary)Fission: When an organism splits into two or more separate individuals

  • Ex. Anemones, Flatworms

• Parthenogenesis: Offspring develops from unfertilized eggs

  • Ex. Aphids

• Haplodiploidy: Males are haploid (unfertilized) and Females are diploid (fertilized)

  • Ex. Bees

Explain the two-fold cost of sex.

• In a population of females reproducing asexually everyone can produce young

• In a population of females reproducing sexually only females can produce young

• In summary the asexual population can produce 2X as much as the sexual population

Understand why asexual reproduction is less common.

• Asexual reproduction is less common and is usually brought about by factors such as:

  • Density, Length of Day, and the Availability of Resources

• Parasites frequent populations with a more common genotype aka asexual host populations leading to widespread decimations and deaths

• Asexual hosts can only rely on random mutation to adapt to evolutionary changes regarding parasites etc.

• Sexual populations on the other hand have genetic recombination meaning they can withstand and undergo evolutionary resistance to certain parasites etc.

Compare internal and external fertilization.

• Internal fertilization occurs within or near a female reproductive tract

  • Courtship/mating behaviors usually follow

  • Increased parental care

  • Internal gestation or embryonic development in egg

  • Requires compatible morphology

• External fertilization occurs in the environment where a female releases eggs and male sperm can fertilize them

  • Requires a moist environment for aided sperm mobility

  • Synchronous spawning is the reproduction btw. many individuals which is common in external fertilization

  • Factors that can be disrupted with this is:

    • Timing

    • Environmental Cues

    • Chemical Signs

    • Courtship

Examine adaptive benefits of unusual reproductive strategies.

• Sperm Removal: Specialized structures males can have which removes the sperm of other males in female repro. tract

• Sperm Storage: Where females can store sperm in spermatheca until the female will choose a certain one best suited for either environment or fitness levels

• Sperm Plug: Where males secrete a special substance blocking the female repro. tract from other males to put sperm into, this is not temporary but prevents females from mating with males immediately after giving preference to first male.

• Sex Reversal: When an organism can change their sex for increased mating success

Compare how animals acquire food

• They can acquire food through various methods such as:

  • Ingestion: Intake of food

  • Digestion: Breakdown of food

  • Absorption: Nutrients are taken up from food

  • Elimination: Waste is excreted

• The various feeding methods are:

  • Filter feeding: Straining small food particles from substances

  • Substrate feeding: Living in or on the food source

  • Fluid feeding: Sucking nutrient rich foods from host

  • Bulk feeding: Consuming large particles of food

Review the digestive system in mammals

• All mammals besides sponges have extracellular digestion

  • Gastrovascular Cavity:

    • The site for both digestion and absorption of food, single opening for ingestion and secretion

    • Mouth and anus is one opening

  • Digestive Tract:

    • Organized into compartments for absorption, digestion, and storage

    • Mouth and anus are two separate openings

      • Ex. Humans, Mammals

• Bacteria, Archaea, and some protists have intracellular digestion

• Human Digestive System

  • Stomach/Oral Cavity

    • The mouth enacts ingestion and carbohydrate digestion (mechanical digestion is chewing and chemical digestion in saliva)

    • The stomach functions in storage and protein digestion with gastric juices (chemical digestion)

  • Intestines/Excretion

    • Small Intestines: main site for digestion and absorption of nutrients using enzymes and microvilli

    • Large Intestines: functions in water reabsorption, symbiotic bacteria assist in digestion

    • Rectum/Anus: the a site for storage and waste excretion

Examine different modes of digestion: mechanical, chemical, and by symbionts

• Mechanical Digestion:

  • Teeth: Breaks food into smaller pieces and increases surface area for digestion

  • Gizzard: Found in a birds, crocidiles, and some fishes, grinds food with grit (little stones, sand) and muscular walls

  • Regurgation of Curd: Allows ruminants to rechew food, they chew it and spit it out then rechew it again once cellulose has been partially broken down by microorganisms in the rumen

• Chemical Digestion:

  • Occurs at various sites in the body

    • Mouth (saliva): Carbohydrates

    • Stomach: Proteins

    • Small Intestine: All nutrient types

  • Accessory organs aid in chemical digestion without actually doing it:

    • Pancreas: Produces enzymes for digestion

    • Gallbladder: Stores and holds bile

    • Liver: Creates bile for fat digestion

• Symbionts Digestion

  • Bacteria in the digestive systems of omnivores and herbivores break down and digest cellulose as they lack enzymes

    • Can be found in rectum, cecum, and large intestine

Consider how diet affects the digestive system

• Diet affects the size and shape of teeth

  • Ex. Carnivores have sharp canines while Herbivores have long thick molars

  • Ex. Omnivores have a combination of both

• Diet can affect the size of certain digestive organs

  • Ex. Herbivores have longer intestines as their diet consists of longer digestion

  • Ex. Ruminants usually have longer digestive organs while Carnivores have fairly simple organs

Explore the importance of the microbiome

• It is a community of diverse bacteria which aid in digestion and health AKA “healthy gut” or “probiotics”

  • They can ferment dietary fiber into short fatty acid chains

  • Synthesize vitamins B and K

  • They metabolize bile and aid in immune support

Define and describe homeostasis.

• Homeostasis is the persistent maintenance of internal environment of cells and organs independent of it’s external environment

  • It functions in pH, temperature, glucose, and salinity

  • Its highly important for enzyme function, metabolic efficiency, and cellular integrity

  • It regulates through Negative Feedback

    • Insulin production increases with elevated glucose levels, promoting glycogenesis while inhibiting gluconeogenesis to restore normal blood glucose.

Compare costs and benefits of temperature regulation modes.

• Regulators:

  • Organisms regulate their internal environment independent of an external one

    • When thinking about homeostasis think about regulation, homeostatic processes

• Conformers:

  • Organisms conform/change their internal environment to their environment

    • Animals may regulate some conditions and conform to others

• Endotherms:

  • Are capable of maintaining and creating their own internal body heat through metabolic processes

• Ectotherms:

  • Rely on their external environment to regulate body temperature

• Poiklotherms:

  • Organisms have a variable body temperature depending on their environment

  • Conformer

• Homeotherms:

  • Organisms have a consistent/strict internal body temperature independent of their environment

  • Regulator

• Costs vs. Benefits

  • Ectotherms:

    • Less energy is expended to maintain

    • Inactive during unfavorable temperatures

    • Enzymes are functional along a range of internal conditions

  • Endotherms:

    • More energy is expended to maintain

    • Active despite poor conditions

    • More efficient due enzyme optimization of stable conditions

Define mechanisms of heat loss and gain.

• Mechanisms of heat loss and gain are:

  • Evaporation: Loss of heat through liquid turning to gas

  • Radiation: Emission of heat through electromagnetic radiation

  • Convection: Moving air or water removes radiated heat

  • Conduction: Direct transfer of heat between substances/objects

Examine strategies for regulating body temperatures in hot and cold conditions.

• Evaporation allows the body to stay cool and maintain internal homeostasis

• Vasodilation expands veins increasing blood flow and expelling heat to the environment

• Fur and Fat in mammals allows the retainment of heat in unfavorable conditions

  • Mammals may raise fur and birds may raise feathers to trap heat during the cold

Define methods of regulating water balance.

• Osmotic concentration measures the solution concentration per liter

• Osmoconformers: Match their osmotic conc. with their environment, organisms have a relatively equal amount of water to their environment (isotonic)

• Osmoregulation: Regulate/Control their osmotic conc. independent to their environment (hyper or hypotonic), organisms may have less or more water than their environment

  • Isotonic: Organism [water] = Environmental [water]

    Hypertonic: Organism [water] < Environmental [water]

    Hypotonic: Organism [water] > Environmental [water]

Examine osmoregulation in different habitats.

• Freshwater Env.:

  • Fish are hypertonic to their environment meaning they gain water by osmosis and excrete dilute urine

• Marine Env.:

  • Fish are hypotonic to their environment, due to being dehydrated causing them to drink seawater and excrete salts while retaining water

• On Land

  • Terrestrial organisms are hypotonic to their environment, using mechanisms of evaporation, secretion, and excretion can lead to water loss

Compare three types of nitrogenous waste.

• 3 types of nitrogenous waste is Ammonia, Urea, and Uric acid

• Ammonia:

  • Most toxic

  • Less costly to perform

  • No internal water loss so it must be diluted in water

  • Aquatic invertebrates and some vertebrates

• Urea

  • Low toxicity

  • Moderate water loss

  • Terrestrial animals, Mammals

  • More costly to perform

• Uric Acid

  • Little to no toxicity

  • Reduces water loss, doesn’t dissolve in water

  • Most costly to perform out of all nitrogenous waste mechanisms

  • Birds, Insects, and Reptiles

Outline 4 basic steps of excretion.

• The four steps are Filtration, Reabsorption, Secretion, and Excretion

• Filtration:

  • Collect substances( water, small solutes) from the blood

• Reabsorption:

  • Recover necessary nutrients (water, important solutes) and substances back into the body

• Secretion:

  • Add toxins and excess ions to the filtrate

• Excretion

  • Filtrate filled with waste and toxins are released as urine

Examine mammalian excretory system structures and functions.

• In mammals we have various structures that facilitate the excretory system:

  • Kidneys have Nephrons which function in secretion and filtration and a glomerulus that is the first site for filtratio n

    • Nephrons have a Bowmans Capsule, Proximal Tube, Loop of Henle, Distal Tube, and the Collecting Duct

  • The Bowmans Capsule (surrounds glomerulus):

    • The main site of filtration in the Nephron

  • The Proximal Tube:

    • Main site of reabsorption

    • Reabsorbs water, ions, salts, and nutrients

    • Secretes toxins into filtrate, nitrogenous waste

  • Loop of Henle:

    • Main site of the reabsorption of WATER ONLY

    • Function in the maintenance of the osmotic gradient

    • Length correlates with the concentration of urine, longer loops are associated with more concentrated urine due to increased reabsorption capabilities.

  • Distal Tube:

    • Main site of further reabsorption of water and solutes such as ions of filtrate before excretion in collecting duct

  • Collecting Duct:

    • Main site for the final excretion of filtrate in the form of urine

  • Every part of the nephron functions in water reabsorption

Compare water conservation strategies in animals.

• Terrestrial Organisms:

  • Desert mammals: mainly hypertonic urine and their nephrons maintain a steep osmotic gradient

  • Freshwater mammals: shorter nephron loops and a lower urine concentration

  • Birds: produce uric acid allowing for higher water efficiency

• Aquatic Organisms:

  • Freshwater fish: excrete large volumes of dilute urine and conserve solutes through reabsorption of ions from filtrate

  • Marine fish: filtration levels are low so little urine production, chloride cell’s gills help in salt balance maintenance

Compare gas exchange structures in different animal systems.

• Gas exchange in water

  • Water has less O2 than in air

  • It’s facilitated by simple diffusion

  • Gills increase surface are increasing efficiency

    • Ex. Fish, Sharks, Mollusks, Crustaceans

  • In Fish countercurrent flow maximizes oxygen absorption by allowing water to flow in the opposite direction to the blood flow, enhancing the gradient for oxygen transfer.

• Gas exchange on land

  • Insects

    • Have tracheae (air tubes) branching within the body

      • Deliver oxygen and co2 transfer

      • Separate from circulatory system

      • Hemolymph distributes nutrients and collects waste

  • Tetrapods

    • Lungs are primary/sole gas exchange organ

Explore different ways that animals breathe.

• Breathing: maintains high O2 and low CO2 at respiratory surface

  • Differences in structure and efficiency

• Amphibians

  • Lower lung surface area than amniotes

  • Use positive pressure breath, like filling a ballon with helium forcing air into a structure

    • Lowers floor of throat, contracts throat muscles

    • Push air from mouths to lungs and gas exchange occurs

• Birds

  • Air sacs (bellows) keep air flowing

  • 2 cycles of inhalation/exhalation to complete air circuit

    • Creates unidirectional flow of air in the lungs

      • Gradient of lungs favor new air coming in

      • Prevents mixing of old air and new air

• Mammals

  • Negative pressure breathing, ensures high rates of oxygen delivery

    • Muscular contractions expand thoracic cavity, gives our body more space

      • Change in space causes lower pressure in lungs

    • Air rushes in -inhalation

    • Muscles relax and you breath out

      • Causes volume of thoracic cavity to reduce

    • Air is forced out through exhalation

Describe how the structure of hemoglobin helps maximize distribution of oxygen in mammals.

• Hemoglobin

  • 4 Subunits each having a heme group with an iron atom

  • Each iron atom binds 1 Oxygen molecule, 4 total for each heme group

    

    • Oxygen binds with iron

      • Binding increases affinity of hemoglobin for more O2

      • CO2 reduces affinity for O2 and promotes O2 unloading to tissues

        • Changes in blood pH decreases affinity for O2

    • Nearly all vertebrates expect the Antarctic block ice fish

• Hemocyanin

  • Oxygen binds with coper

  • Mollusks, arthropods (basal insects)

Examine how CO2 is transported from tissues to the lungs to be removed in mammals.

• CO2 is a waste product of cellular respiration

  • Most is converted to bicarbonate in erythrocytes, then travels in plasma to lungs

  • When we get to the lungs , bicarbonate is converted back to CO2, which then diffuses into the alveoli to be exhaled/removed.

• Medulla Oblongata controls breathing

  • pH of CSF indicates CO2 level

  • Hydrogen from bicarbonate reaction lowers pH

• Tells your body to increase breathing as metabolic activity increases

Compare open vs. closed circulation systems.

• Circulatory System: Functions in distribution of O2 and nutrients and collection of CO2 and waste

  • Found in most animals with large or complex body plans or high metabolic needs

  • Animals w/o a circulatory system with a gastrovascular cavities who exchange material through diffusion, Ex. Sponges, Jellies

• Open Circ. System

  • Organisms have a heart that’ll pump hemolymph through circulatory vessels to hemocoel

    • Direct delivery of resources to the tissue in hemocoel

  • When the heart relaxes it changes pressure in the body pulling hemolymph back into the heart

    • Allows waste to be filtered

  • Pros: Less energetically costly, Direct delivery of nutrients/waste btw. hemolymph and tissues

  • Cons: Lower pressure and flow rate, resource delivery is not specified to tissues/organs

• Closed Circ. System

  • Organisms have blood confined to vessels with the heart pumping blood that branch and infiltrate tissues and organs

    • Exchange btw. blood, interstitial fluid, and body cells

  • Pressure and gradients ensure efficiency of delivery of O2 and nutrients to specific tissues

Examine differences in habitat and lifestyle of vertebrates with single vs. double circulation.

• Single Circulation Organisms

  

  • Blood passes through the heart once

  • Organisms have 1 atrium and 1 ventricle

  • Moves from heart to gills, to the body, and back to the heart

  • Lower blood pressure in the body

  • Mainly aquatic organisms

• Double Circulation Organism

  • Blood passes through heart twice, 2 circuits

  

  • Pulmonary Circuit

    • Starts at the R side of the heart then O2-poor blood goes to lungs/skin, then O2-rich blood goes back to L side of heart

  • Systemic Circuit

    • Starts at L side of heart, then O2/nutrient-rich blood goes to

      body, finally collect CO2-rich blood and waste goes back to R side of heart

    • Higher blood pressure, red blood cell returns to heart twice

Explore circulation in mammals.

• Amphibians

  

  • 2 atria and 1 ventricle w/ a ridge

  • Gas exchange w/both skin and lungs

  • Adjust circulation when lungs are not in use

• Reptiles

  

  • 2 atria and 1 ventricle w/incomplete septum

    • Mixing of oxygen rich and oxygen poor blood

  • Can bypass pulmonary circuit when underwater

• Mammals/Bird

  

  • 2 atria and 2 ventricles

  • Creates more CO2 and waste

  • Requires higher oxygen rate for metabolic processes, endothermy

Compare the structure and function of the three types of blood vessels.

• All are have a central cavity lined by endothelium

• Arteries, carry blood away from heart

  • THICK WALLS

  • Smooth muscle controls blood flow as it’s flexible

  • Connective tissue is strong to support high blood pressure/flow

• Veins, carry blood to the heart

  • 1/3 as thick as arteries

  • Same tissues as arteries

  • Blood flows at lower pressure

  • Valves present to prevent backflow, maintains unidirectional flow

  Capillaries, connects arteries and veins

  • Diameter slightly wider than red blood cell

  • Thin walls for gas exchange between interstitial fluid and blood

  • Flow varies based on organ

    

    • Fenestrated increases permeability

      • Digestion,Excretion

    • Sinusoid, movement of blood cells and plasma proteins

      • Liver, Spleen, Bone Marrow where blood cells are moving

Examine how blood pressure and flow change through circulation.

• Ventricular contraction generates pressure

  • Generated by the hearts diastole and systole circuit

• Systolic pressure

  • Highest pressure, ventricles contract

  • Lub part

• Diastolic pressure

  • Lower pressure, arteries bounce back and heart relaxes

  • Dub part]

• As we move away from the heart mean pressure decreases

  • Part is due to narrowing of blood vessels as theirs more resistance of walls of blood vessels

• Blood flow: Rate or Velocity when blood enters arterioles, capillaries

• LARGE VESSELS BRANCH INTO SMALLER VESSELS

  • Increase in TOTAL cross-sectional area decreases velocity

  • Ex. Garden house on regular setting water is flowing strong and really fast, when you change the head the same amount of water but pressure is not as strong

Explore the different components of vertebrate blood.

• Plasma 55% of Blood

  • Liquid matrix where nutrients, nitrogenous waste, gases, and hormones

  • Dissolved ions, help buffer blood and maintain osmotic balance

    • Affect muscle and nerve activity

  • Plasma Proteins

    • Buffer of blood

    • Antibodies

    • Clotting factors

• Erythrocytes 45% of Blood

  • Most numerous blood cells

  • Biconcave shape, increase surface area

  • Hemoglobin

    • O2 transport

  • Lack nuclei and mitochondria

    • Because the main function is to transport hemoglobin to transport CO2

  • Each erythrocyte transports 1 billion molecules in the body

• Leukocytes <1% of Blood

  • 5 major types

  • Function is to fight infection

    • Phagocytic removal of microbes

    • Immune response against unfamiliar substances

  • Increases in number when you’re sick

• Platelets <1% of Blood

  • Fragments of specialized bone marrow cells

  • Functions as clotters, facilitates clotting (positive feedback system)

    • Breaks in blood vessels attracts platelets

    • Clotting factor is released which triggers enzyme to convert coagulant from inactive to active to patch the break

    • Coagulant aggregates into threads forming a clotting structure

Define countercurrent exchange and its applications in thermoregulation, osmoregulation, and excretion.

• Countercurrent exchange

  • Transfer for some property btw. two bodies flowing in opposite directions

    • Ex. Water, Heat, and Oxygen

    • Bodies are vessels containing blood, filtrate or other secretion

  • This process takes advantage of gradients to move from a high conc. to a low. conc. (passive transport)

  • This is a continuous and slow gradient to maintain and maximize efficiency

Examine how countercurrent change can support thermoregulation, osmoregulation, and excretion

• Water < O2 than air

• Gills have larger SA for gas exchange

  • Can be maximized by countercurrent flow by:

    • Creating a gradient ensures increase in diffusion rate of gases btw. blood and gills

    • In countercurrent flow oxygen rich water flow one way why blood moves another way gaining oxygen along gradient.

    • If we had concurrent flow, the efficiency of oxygen uptake would significantly decrease, as the blood and water would be moving in the same direction, leading to less optimal gas exchange.

      • There would be a point of equilibrium as their be no increase of oxygenation of the blood

• In Heat Exchange

  • Warm blood in arteries, cool blood in veins

    

    • Blood flows in opposite direction so heat can be transfered btw. the structures

      • Helps reduce heat loss in limbs

        • Passively conserve metabolic heat

• In the Nephron

  • Mammals produce hyperosmotic urine to reduce water loss

    

    • Relies on countercurrent flow of filtrate and blood=osmotic gradient

    • Osmotic gradient maintained by active transport of salt

      • Water and salt move in opposite directions

    • Very energetically costly

    • WATER IS ALWAYS PASSIVELY TRANSPORTED

Trace the exchange of gases, nutrients, and wastes across various organs and tissues.