Lecture 6 - Prelecture!

Endothermy + Who

A strategy of thermoregulation by generating heat through metabolism

• Among birds and mammals

Ectothermy + Who

A strategy of gaining heat from external sources

• Invertebrates, fish, amphibians, reptiles

Energy Cost difference Between Endotherms and Ectotherms

Endotherm: Cost a lot of energy

Ectotherm: Barely costs energy for SHIT

Temperature Range Between Endotherms and Ectotherms

Endothermy: large range survivability

Ectotherm: small range survivability

Poikilotherm

An organism whose body temperature varies with environment

• Most ectotherms, but some endotherms

• ex: Bats, Hummingbirds

Homeotherms

An organism whose body temperature does not vary with the environment, staying relatively constant

• Typically endotherms, SOME ectotherms >:(

• ex: Fish, invertebrates in stable T env.

5 Adaptions for Heat Regulation

1. Insulation (feathers, blubber, skin)

2. Evaporative Heat Loss (sweating, panting)

3. Behaviour Responses (huddling, posture)

4. Circulatory Adaptions

5. Adjusting Metabolism

Outline Circulatory Adaptions for Heat Regulation

• Vasodilation and Vasoconstriction to increase/decrease the diameter of blood vessels

• Constrict → less blood flow, less heat loss

• Dilate → more blood flow, more heat loss

Counter-Current heat Exchange

• Regulation of body part at a lower temperature to reduce heat loss

• Opposite-direction flowing, they exchange heat to ensure ends are cold and INTERNAL IMPORTANT STUFF is warm!

Thermogenesis

• A form of adjusting metabolic heat production

• Shivering and moving more

Torpor

Temporary (daily) reductions in metabolic activity to lower body temperature and activity

Hibernation

Extended reduction in Metabolic Activity

Basal Metabolic Rate (BMR)

The metabolic rate of an ENDOTHERM at a “comfortable” temperature

• assumes a nongrowing, fasting, and nonstressed animal

Standard Metabolic Rate (SMR)

The metabolic rate of an ECTOTHERM at rest at a specific temperature

• assumes nonstressed, nongrowing organism

Average Daily Rate of Energy consumption for most terrestrial animals

2-4 Times the BMR (Endotherms) or SMR (ectotherms)

Factors that determine Animal Energy budget devoted to activity

• Environment

• Behaviour

• Size

• Thermoregulation

Relation with Maximum Metabolic Rate and Duration of Activity

The maximum metabolic rate an animal can sustain is inversely related to the duration of the activity

Acclimatization + Two examples discussed in class

Physiological Adjustments to Environmental Factors

• ex: Birds/Mammals vary their insulation to acclimatize to season changes

• Subzero temperatures have ectotherms make “antifreeze” to prevent ice formation in cells

Nutrition + How animals get it

Balance between Nutrient Intake and Needs of the body

• Gotten through Ingestion! (Dead or alive, pieces or whole)

2 Things a Diet must Provide

1. Chemical Energy: stored in organic molecules (food, ex: C6H12O6), broken down to ATP for cellular processes

2. Organic Molecules: Building blocks and macromolecules needed to grow, survive, and reproduce

Raw Building Blocks - Organic Molecules

Carbon, Nitrogen, more!

Macromolecules aquired from food

• Protein

• Carbohydrattes

• Lipids

Essential Nutrients

Molecules that animals cannot produce and therefore must receive from the diet

4 Classes of Essential Nutrients

1. Amino Acids (protein)

2. Fatty Acids (fat)

3. Vitamins - organic molecules

4. Minerals - inorganic molecules

How many Amino Acids we cannot synthesize on our own + potential sources

8 of the 20, we cannot make on our own

• “complete” proteins: meat/cheese have all 8

• “incomplete” proteins: plants (need variety)

Fatty Acids our body needs from our diet

Omegas!

3, 6, and 9 >v<

4 Steps of Food Processing

1. Ingestion (swallow)

2. Digestion (mechanical/chem breakdown)

3. Absorption (intake of usable nutrients)

4. Elimination (removal of unusable nutrients)

Suspension/Filter Feeders + Examples

A feeding mechanism by which organisms sift and strain small food from water

• ex: Baleen Whales, Clams

Substrate Feeders + Examples

Organisms that LIVE ON TOP OF their food source 😋

• ex: caterpillars, maggots

Fluid Feeders + Examples

Organisms that suck nutrient-rich fluid from a living HOST >:(

• Mosquitoes, bees, aphids

Bulk Feeders: Whole Feeders vs Piece Feeders Structure

Eat large food (typical…)

• Whole: Modified Jaws to eat food

• Piece: Tear pieces with teeth, pincers, claws, etc.

Purpose of Mastication

To break down food into smaller molecules for better absorption

Mechanical Digestion

Breaking down food into smaller pieces by chewing

• Increasing SA:V Ratio for more absorption (think cells!)

4 Types of Teeth Adaptions for better Mechanical Digestion

1. Incisors - thin and flat for biting and cutting

   • INCISIONS WITH AN “r” INSTEAD!!!

2. Canines - pointy to kill

3. Premolars - sharp to shred

4. Molars - flat surface to grind

Sets of Teeth for Omnivores, Carnivores, and Herbivores

• Omni: Incisors, Canines, and Premolars/Molars (all)

• Carni: All except incisors

• Herbi: Reduced Incisors and Canines

Chemical Intracellular Digestion (atypical)

• Cells engulf Food particles and enzymes break them down in vacuoles

Chemical Extracellular Digestion (typical)

• Food particles are broken down by enzymes OUTSIDE of cells

• Ex: Saliva >:)

Gastrovascular Cavity Structure + f(x)

Digestive Tube with 1 opening

• In simple body plans

• “Incomplete” or “two-way” gut that both digests and distributes nutrients

Alimentary canal Structure + Function

Digestive System with two openings (mouth + anus)

• more complex animals, food goes on way and out the other

• Segmented parts for digestion/absorption (more efficient)

Accessory Glands in Digestion

• Salivary Glands

• Pancreas

• Liver

• Gallbladder

Location of Amylase + For what kind of Sugar

Mouth: for small polysaccharides

Small Intestine (pancreas): for disaccharides

Small Intestine (epithelium): for monosaccharides

Location of Protease = For what kind of Polypeptide

Stomach: Small polypeptides

Small Intestine (pancreas): even smaller polypeptides

Small Intestine (epithelium): AMINO ACIDS

Location of Lipase + What is breaks down

All in the Small Intestine, breaking Triglycerides into Glycerol, Fatty Acids, [and thus monoglycerides]

How 400 Bacteria were discovered in our digestive tracks

• PCR!!!! >:D

How Absorption is Efficient in Humans

• Our small intestine is long (6m) and folded

• Atop are villi → finger-like projections that x10 SA

• On epithelial cells are Microvilli → x 50 SA

SA: 300m²

Mutualistic Symbiosis + Core Example

• Mutually Beneficial Interactions between two Species

• Ex: animals cannot digest cellulose, so we have bacteria and protists in fertilization chambers to digest

Bird Fermentation Chamber vs. Human Fermentation Chamber

• Birds: Crop

• Mammals: Cecum

Outline the Carnivore Digestive System

• Animal Tissue is easily digested!

• Stomach is larger and expands,, sorter large intestine and smaller Cecum

Outline the Herbivore Digestive System

• Plant tissue is hard to digest

• Stomach: smaller so an organism can eat small amounts continuously

• Longer intestine + Larger Cecum, MORE SA!

Outline the Ruminants Digestive System

4-Chamber Stomach:

• Chewed Food (chamber 1 and 2)

• Regurgitates “Cud” and rechews

• Reswallows Cud (chamber 3, water removal)

• Chamber 4 (more digestion)

Outline the Coprophagy Digestive System

• Eats feces to recover unabsorbed nutrients…

• Large intestin + Cecum Digest, then small intestin absorbs (why they have to shit then eat…)

Types of Nitrogenous Waste (Elimination)

1. Ammonia [aquatic] (most toxic), high water loss, least E cost

2. Urea [land species], medium toxic/water loss/E cost

3. Uric Acid [land reptiles/birds], non-toxic/low water loss, high energy cost D:

Steps of Excretory System (Tubules + large SA for solute and water exchange >v<)

1. Filtration (passive)

2. Reabsorption (active)

3. Secretion (active)

4. Excretion

Filtration in the Excretory System

All small molecules go from the blood to the excretory tubes by passive transport (ex: H2O, salt, sugar, AA, Ammonia)

Reabsorption in the Excretory System

Selectively reclaim valuable solutes (water, sugar, AA)

• THROUGH ACTIVE TRANSPORT

Secretion in the Excretory System

• Nonessential solutes and waste are added from the blood to filtrate

• ACTIVE TRANSPORT!

Excretion in the Excretory System

• Filtrate (nitrogenous waste), release from the body