WFC 130 Midterm 1
how does energy use compare between lab and field?
Values of MR in field are 3X higher than in lab
what is energy
(E) -common currency of all life
what is correlation selection?
- Correlational selection favors particular combinations of two traits expressed together in the same individual, but may not affect the distribution of either trait alone. - Correlational selection is the force by which traits become functionally integrated with one another
maximum Metabolic rate (MMR)
- possible to achieve.
How do adaptations occur?
-Adaptations emerge slowly through a variety of processes, leading to the EVOLUTION of certain traits -(natural selection)
what are the central themes of physiological ecology?
1. Diversity 2. Unity 3. Homeostasis 4. Principle of Allocation 5. Size matters 6. Behavior 7.Physical/chemical laws apply 8. Adequacy, not perfection 9. Emergent properties 10.The 'Abiotic Master Factor' 11. A Spectrum of Detail
Natural Selection is a Relative Process
-Adequacy not perfection -Natural selection increases fitness, but produces systems that function no better than they must. Why isn't everything 'optimized'?: —design need only be better than the alternative. —solution to one env. challenge may be unacceptable in another -Function balances Demand: Animal design (physiological processes) often have competing demands. The most common evolutionary outcome (adaptation) may be a balance between competing demands.
short term modulation 1b: basic allosteric modification?
-Allosteric modification = binding of molecules ('ligands') to a protein resulting in a conformational change to that protein. -Protein function is influenced by conformation (shape) -Therefore, allosteric modulation of proteins impacts their function! • Binding of a ligand to protein can change its shape and alter binding affinity for another ligand e.g. Glucose binds to hexokinase, creating a 50-fold increase in the affinity of the hexokinase for ATP • Link between two ligands can be positive (Cooperative) or negative (Competitive
Alternative splicing
-Alternative splicing is not a random process!!. -It's controlled by regulatory proteins -The proteins bind to specific sites on the pre-mRNA and controlling which exons should be used. -Different cell types may express different regulatory proteins, so different exon combinations can be used in each cell type, leading to the production of different proteins.
Regulation after transcription: RNA processing
-Although, gene expression is often controlled primarily at the level of transcription, gene expression can also be regulated at RNA processing stage. -When a eukaryotic gene is transcribed in the nucleus, the RNA is pre-mRNA. The pre-mRNA is modified to become mRNA, which include splicing. -Alternative Splicing: -Pre-mRNA molecules have sections that are removed from the molecule (introns), and sections that are linked to make the final mRNA, called exons. This process is called splicing. -In the process of alternative splicing, different portions of an mRNA can be selected for use as exons. This allows either of two (or more) mRNA molecules to be made from one pre-mRNA.
what is an adaptation?
-An adaptation is the product or process of evolution by natural selection -An organism's physiology, morphology, & behavior are usually very well matched to the environment it lives in.
what important change can be caused when there is changes in the DNA sequence
-At several points in the evolution of animals, whole genomes or regions were duplicated. Many of the duplicated genes were eventually lost, but many were retained and diverged to form gene families. Many of the anatomical and functional specializations of vertebrate are a result of these genomic duplications. Ex. Hox gene family, a group of genes that controls the development of an embryo, and determines the type of appendages (i.e., legs, wings, etc)
why changing protein abundance?
-Because increasing the amount of protein can increase the rate of reaction. Thus, increasing gene expression can help an organism cope with environmental challenges
why are we interested in the Animal x environment interaction?
-Biomes Range Widely in conditions such us temperature and precipitation -Oxygen: Anoxia to supersaturated - Pressure: < 1atm to ~ 1200atm - Salinity: Deionized water up to many-fold more concentrated than seawater -and environments can be stable or highly variable
what are the homeostasis key concepts?
-Controlled variable: property that is being kept constant or relatively constant by the system's activities. -The set point is the level at which the controlled variable is to be kept. -Feedback occurs if the system uses information on the controlled variable itself to govern its actions. -In negative feedback, the system responds to changes in the controlled variable by bringing the variable back toward its set point; that is, the system opposes deviations of the controlled variable from the set point. Ex. Hunger-Foraging-Change in stomach volume -Positive feedback loops cause explosive responses. They maximize changes in the regulated variable. Ex. Vomiting -toxins
what is the relationship between control processes and time
-DNA: adaptation 100s to 1000s of generations -transcriptional control, RNA processing control, RNA transport control, translation control, mRNA degradation control: acclimation/acclimatization days to weeks -protein activity control: short term modulation msec-minutes
Physiology is also Unifying
-Despite this great diversity, there are many commonalities within physiology - unifying themes that apply to all physiological processes Ex: DNA Ex: HSPs
Indirect measure
-Difference between the energy value of all food taken in and the energy value of the excreta (feces and urine). • Assumes no change in the composition of the organism (not growing, no storage)
a spectrum of detail
-Each level of biological 'organization' comes with its own scale of physiological 'detail' that can be studied -Complexities and limitations of study at each scale -Selecting appropriate scale(s) to study is a challenge -Extrapolating between scales is a challenge
What are Enzymes?
-Enzymes are biological catalysts that convert a substrate to a product. -Enzymes, have three properties: (1)They are active at very low concentrations within the cell; (2)They increase the rate of reactions but they themselves are not altered in the process; (3)They do not change the nature of the products. -Many enzymes possess non-protein components, called cofactors that could be metals, such as copper, iron, magnesium, zinc, and selenium. Or organic cofactors (or coenzymes), are usually derived from vitamins. [more on class about diet & digestive systems] -The rate at what enzymatic reactions occur are referred to as enzyme kinetics. This can be affected by different factors
what is acclimation?
-Functional change over a period of days to weeks when variables are manipulated experimentally. -Usually reversible. -Involves compensation to a single environmental variable. -Ex. Fish held in tanks are acclimated to different temperatures. One variable, temperature, is tightly controlled. -Remember: Laboratory-acclimated
what is acclimatization
-Functional compensation over a period of days to weeks in response to a complex of factors (seasonal changes). -Usually reversible. -Involves compensation to more than one environmental variable Ex. Animal that moves towards higher altitude becomes gradually acclimatized. -Remember: Field- or Seasonal-acclimatized
transcriptional control of protein synthesis p2
-Gene regulatory proteins bind to specific sites on the DNA close to the gene coding sequences. Their effect is to ensure that the right genes are switched on in each cell type at the right time, leading to the differentiation between, for example, nerve cells, gland cells, or epidermal cells. -How do regulatory proteins work? they recognize a region within the promoter sequence of a DNA strand. This small section within the promoter is termed the operator. - Remember: If the polymerase cannot bind properly to the promoter transcription cannot occur. - Gene regulatory proteins can activate or inhibit. The two types of gene regulatory protein, having positive and negative effects, are usually termed transcriptional activators and transcriptional repressors (or gene activator proteins and gene repressor proteins), respectively. - Critical gene regulatory proteins (encoded by master control genes) that serve as key switches for a whole set of other regulator complexes across a range of cell types. - Cell memory. Once a cell has switched to become a particular cell type, with the appropriate genes turned on and off, it passes on this suite of gene expression to its daughter cells through mitotic divisions. This allows the formation of tissues
Carbohydrates
-Glucose and related sugars derived from carbohydrates. • Kreb's cycle is efficient so whenever possible then, animals proceed further with the breakdown of glucose, ensuring that it is more completely oxidized with O2 (aerobic metabolism) • 38 ATP from glucose -Important concepts [check class digestive systems & diet]: - Glycogen synthesis (glycogenesis) - Glycogen breakdown (glycogenolysis). - Dietary glucose is inadequate or when glycogen stores are compromised, animals can produce glucose from noncarbohydrate precursors via gluconeogenesis.
what are the three strategies to maintain homeostasis during challenging conditions?
-Homeostasis in broadest sense - maintenance of 'acceptable' function. -Three strategies to maintain 'homeostasis' during challenging conditions. a. Avoiders - spatial (leave) or temporally (alter physiological state) b. Conformers - can deviate from or abandon a homeostatic setpoint to conform to the environmental challenge c. Regulators - maintenance of 'homeostasis' via physiological or behavioral adjustments -Strategies are not mutually exclusive
what are avoiders
-In time: Changing their physiological state to avoid stressful environment (e.g., hibernation) -Avoiders in space - moving to an unstressed habitat (e.g burrowing & migration). Examples from migrant birds
How are proteins formed?
-In transcription, a DNA sequence is rewritten, or transcribed to RNA. -In translation, the sequence of the mRNA is decoded to specify the amino acid sequence of a polypeptide. environmental factors can influence protein function: pH, temperature, small molecules, etc
Aerobic metabolism
-More efficient ATP production -Kreb's Cycle + Electron Transfer System. -No waste products must be converted.
energy storage: fat vs glycogen
-Most of animals accumulate fat as reserves, irrespective of food composition. Why? Weight & Energy - Weight. Storage of glycogen involves more weight bc of the lower energy content of carbohydrate compared with fat, but also glycogen is deposited in cells with a considerable amount of water (3g water per 1 g glycogen) -Weight per energy unit (g per kilocalorie) Fat 0.11 Protein 0.23 Starch 0.24 Glycogen 1.0 -But... glycogen can provide fuel very quickly, and under anoxic conditions (eg. Heavy muscular exercise blood doesn't deliver enough oxygen) - Energy Kcal g-1 glucose 4.2, fat 9.4
Regulation pre-transcription: Chromatin accessibility
-Most of the genome of a cell is wrapped around histones and rolled into nucleosomes. Under these conditions genes are unable to start the transcription process. -The structure of chromatin needs to be re-arranged to make a gene available for transcription. -Cells can regulate the RNA synthesis by altering the conformation of the gene and changing the ability of the transcriptional machinery to assemble.
Adequacy not perfection
-Natural selection increases fitness, but (in general) produces systems that function no better than they must. -Why isn't everything 'optimized'? Optimal is a relative term—design need only be better than the alternative. Multiple selective pressures could select different phenotypes
there is no free lunch
-Nearly all adaptations have secondary consequences Ex. Herbivorous mammals, Radical specialization precludes generalist feeding -While some adaptations expand opportunities to an organism, others may restrict them Ex. Lungless salamanders (Plethodontidae) Lunglessness is derived character, Exploit cold streams, but tied to moisture
Definition of Adaptation: Its Use and Misuse
-Often reserved for characters or traits in an animal that is the result of selection pressures.: adaptive trait -However, it is more correct to view adaptation as a process whereby natural selection varies the gene frequency that affects fitness for that environmental variable -Therefore, this definition implies multi-generational timescales occurring slowly and is not reversible -Ex. Bears may possess a suite of adaptations that enable them to survive long cold winters, but they do not "adapt" every year to cold weather.
Translational control of protein synthesis
-Once an mRNA arrives in the cytoplasm, it may or may not be translated to make proteins. -Two key determinants of how much protein is made from an mRNA are: - Its "lifespan" (how long it floats around in the cytosol) - How readily the translation machinery, such as the ribosome, can attach to it. -Modulating the amount of ribosomes, initiation factors, or changes in the activity of these factors through phosphorylation or dephosphorylation, result in changes in the rate of protein synthesis -Therefore, phosphorylation can act as a "switch" In addition, each of these initiation factors can bind inhibitory proteins. -All these mechanisms allow cells to control global changes in translation rates.
Principle of Allocation
-Organisms cannot simultaneously maximize all life's functions •Resources and Conditions (R/C) constantly vary (Energy, nutrients, seasonal conditions) •R/C combination produces habitats •R/C gradient shapes the animal's response: •Behavioral •Morphological •Physiological/Biochemical •Genetic (Adaptation) -R/C gradient leads/equals animal response constrains
what are Darwin's 4 postulates
1) Individuals within species are variable 2) Some of these variations are heritable 3) In every generation, more offspring are produced than can survive 4) Survival and reproduction are not random. [Individuals with the most favorable variations are the ones that survive to reproduce, or the ones who reproduce the most] ...SURVIVAL OF THE FITTEST
what is short term module 1c allosteric modulation by phosphorylation?
-Phosphorylation, is the process by a phosphate group is attached to a protein. The effect of phosphorylation varies from protein to protein: some are activated by phosphorylation, while others are deactivated. -Phosphorylation alters the protein's conformation of protein to which it attaches, and allosterically change the active binding sites -Protein kinase = transfers phosphate group from ATP molecule to the target protein. -Protein phosphatase = removes phosphate groups from phosphorylated proteins
Why should we care about molecular biology in Ecophysiology?? hummingbird example
-Ruby-throated hummingbirds which travel distances of ~800 km, are able to increase their body mass by ~ 50% in just 4 days -Behavioral adjustments: Using torpor at night possibly combined with evening hyperphagia. Increases in the size and activity of gut and liver, digestion times, and digestive enzymes. Particularly, the activity of liver fatty acid synthetase (FAS) and 9-desaturase, which catalyzes de novo synthesis of fatty acids, increases in some pre-migratory fattening birds. -Requirement for exogenous fatty acid increases in the flight muscles as the activity of mitochondrial enzymes involved in fatty acid oxidation such as citrate synthase (CS), hydroxyacylCoA-dehydrogenase (HOAD), carnitine palmitoyltransferase (CPT) also increase Hummingbirds, seasonal expression of these enzymes???
Protein degradation
-The structural changes in damaged proteins recruit enzymes that mark the protein for degradation. -These enzymes transfer a small protein called ubiquitin to the damaged protein. -Once the ubiquitination machinery has attached a ubiquitin chain to the damaged protein, the protein is bound by a multiprotein complex called the proteasome. -Proteolytic enzymes within the proteasome degrade the ubiquitintagged proteins to amino acids
What is animal physiology?
-The study of how animals work" ~ Knut Schmidt-Nielsen -The study of structure and function of the various parts of an animal, and how these parts work together to allow animals to perform their normal behaviors and to respond to their environments". Moyes & Schulte •Studies of diverse organisms to elucidate fundamental mechanisms •Evolutionary origins of physiological traits (Adaptive significance) •Environmental/Ecological questions of animal function in current and future ecosystems
emergent properties
-The whole is often more than the sum of its parts •At each level of biological organization, properties emerge that could not be predicted from the previous level •Increased physiological complexity demands more complex integration. •Increased complexity makes understanding more challenging •Understanding physiological function (at many levels) is most valuable when interpreted in the animal's environmental context
transcriptional control of protein synthesis
-Transcription is controlled by an RNA polymerase enzyme, which makes new RNA from a DNA template. -A polymerase acts when it contacts a specific region of DNA called promoter, which contains the "start sequence" signaling where RNA synthesis should begin. - RNA polymerase can attach to the promoter only with general transcription factors, which must be bound to the operator site (next to the promoter) before any transcription by RNA polymerase can occur. *supplemental audio-visual material General transcription factors: proteins that bind to specific sites in the DNA to activate transcription
what are the fuels for aerobic metabolism
-carbohydrates -lipids -amino acids
What is the comparative method
-comparing different animals in different environments -By comparing different animals, physiologists are able to describe how different animals meet their needs under particular environmental conditions, and thus, how physiology mediates interactions between organisms and their environment, use physiological info to reconstruct phylogenetic relations, identify model systems for studying particular physiological functions.
direct measure of heat production
-direct calorimetry 335 J melts 1 g ice 1 calorie heat required to raise 1g of water 1o C
Total heat production " & the "inborn fire"
-heat produced by an animal is proportional to O2 consumed and CO2 produced -animal "heat" is a byproduct of metabolism
Lipids
-in the form of fatty acids are stored in combination with glycerol as "triglycerides" (more specifically called triacylglycerols) • They are highly concentrated fuels because they can be stored in an anhydrous state (i.e., no water). • Many animals contain cells that are specialized for the synthesis, storage, and mobilization of triacylglycerols (Ex. White adipose tissue in vertebrates). • In vertebrates, triacylglycerol is hydrolyzed back to fatty acids and glycerol by lipases; the resultant process is termed lipolysis and is upregulated by a variety of hormones, including epinephrine, norepinephrine, glucagons, and adrenocorticotropic hormone (ACTH). ... STRESS!
what environmental factors can influence enzyme function
-pH -temperature -small molecules etc
what is short modulation 1a: formation of protein complexes
-protein subunits assemble to form a functional protein -affects protein activity via existing proteins
as ecologist why phenotypes are not perfect
-selective landscape can change -select pressures will change over years
what is homeostasis
-stability of the internal environment -'milieu interieur' = distinct internal environment, Claude Bernard -Example: Body temperature in endotherms
what is metabolism?
-sum of all biological transformations of energy and matter overall use of chemical energy
Examples of animal physiological adaptations for their environment?
-the bar-headed goose fly over the Himalayas , while humans and most other animals at that altitude would perish? -Anna's hummingbird dive at 385 body lengths/second -the wood frog to freeze SOLID, thaw and continue living?
what are the homeostasis challenges: major environmental factors?
-the big three: temperature, oxygen, and water (and ions) -other specific to certain habitats: hydrostatic pressure in deep sea -environmental variation: temporal (seasonal, daily) and spatial (large scale: oceanic to freshwater, salmon) and (small scale: microenvironments)
What are the 6 steps at which gene expression can be controlled
-transcriptional control -RNA processing control -RNA transport control -translation control -mRNA degradation control -protein activity control
what are the seven things to remember about how natural selection operates?
1.Selection must improve Fitness: 'Adaptations' increase the ability of an individual to reproduce and survive in its environment. It's all about Reproduction! 2.Populations evolve gradually over time as natural selection acts upon individuals. (i.e., Individuals are the unit of natural selection). 3.Natural selection acts on phenotypes, but evolution consists of changes in gene frequencies. must be heritable. (i.e., evolution can only occur when selected traits have a genetic basis 4.Natural selection is "backward-looking", not "forward-looking" (i.e., each generation is a product of selection by environmental conditions on the prior generation ) 5. Natural selection acts on existing traits (i.e., novel features can evolve because selection gradually acts on other features that initially have other purposes). Example: Panda's 'thumb' -remodeling wrist bones and tendons into 6th digit for bamboo stripping 6.Mutations arise randomly, but evolution by natural selection is not random. It is controlled by changes in the environment, But not with any directed intent.The environment did not influence the original appearance of the trait (that is random). If trait is advantageous, it is selected for and retained (non-random) 7.Cannot assume that differences among populations or species are adaptive just because they exist and their function 'makes sense' • some traits may persist if do no harm or are linked with some other beneficial trait • Adaptive physiological traits should have evolved for their particular function • What if a trait arose for one function, but now serves a secondary function? Ex: bird feathers & Exaptation Summary: Adaptation is complex, perhaps hard to define.
What are some potential ways to modify protein function to cope with environmental stressors?
1.short term modulation:1-Protein 'action' (Turn existing proteins off/on or modify activity: Post- translational modification of existing proteins) (Step. 6) 1.a. Formation of protein complexes 1.b. Basic Allosteric modulation 1.c. Allosteric modulation by phosphorylation 2. acclimation/acclimatization: protein abundance (synthesis and degradation) 3.adaptation (evolutionary timescales): protein evolution (adaptive changes to protein function)
what is metabolic rate
=energy metabolism/time What does MR tell us? 1. Overall rate of all physiological activities 2. Resource needs 3. Index of energetic demands from the environment
when does an adaptation occur
Adaptation occurs when any change at the DNA level becomes expressed via protein change as a trait that is beneficial in a particular environment and so persists due to selective advantage, eventually spreading through a population
How can we measure metabolism?
Aerobic metabolism: Fuel + O2 turns into CO2 + H2O + ATP + heat -When organisms transform energy from one high-grade form to another high-grade form, the transformation is always incomplete, and some energy is degraded to heat.
How can we measure FMR
After a dose of doubly labeled water, 2H2 18O, the two isotopes equilibrate with total body water (TBW) and then are eliminated differentially from the body. Deuterium (2H) leaves the body as water, while 18O leaves as water (H2O) and carbon dioxide (CO2). Therefore, CO2 production can be calculated by subtracting 2H elimination from 18O elimination -inject a known quantity into animal take blood sample release animal recapture, take 2nd blood sample
Indirect method
Amount of oxygen used in oxidation processes. Animals obtain energy through oxidation of food. The amount of oxygen they consume can be used as a measure of their energy metabolism. -When glucose is oxidized, a fixed proportional relation exists between the amount of heat produced and the amount of O2 used: 2820 kJ of heat per 6 mol of O2. -Similarly, a fixed proportional relation exists between heat production and CO2 production: 2820 kJ per 6 mol of CO2
what is phenotypic plasticity
describes the interplay between genotype, environment and phenotype. A phenotype is considered plastic when individuals with identical genotypes display different phenotypes depending on their environment.
behavior
Behavior is the most important, but least appreciated, component of functional adjustment to the environment.
what happens if there is a genetic variation for the degree of phenotypic plasticity or flexibility
If there is genetic variation for the degree of phenotypic plasticity or flexibility, plasticity or flexibility themselves can evolve and be an adaptive trait if it increases fitness in a particular environment
what is phenotypic flexibility
In contrast, when environmental conditions change rapidly and over shorter timescales than a lifetime, individuals that can show continuous but reversible transformations in behavior, physiology and morphology might incur a selective advantage. This is called phenotypic flexibility.
physical and chemical laws apply
Physics and Chemistry: The Basis of Physiology • Diffusion & Concentration Gradients • Mechanical properties of biomaterials • Electrical potential and membranes
So why don't animals possess every adaptation imaginable to cope with a range of environmental conditions?
Natural selection is relative
indirect method: amount of oxygen used in oxidation processes
Oxygen can be used as a practical measure of metabolic rate because the amount of heat produced for each liter of oxygen used in metabolism remains nearly constant, irrespective whether is fat, carbohydrates or proteins. (20 kJ of heat per liter of oxygen).
calculating metabolic rate
Oxygen consumption 10 mL/minute (min) suppose you know that the animal's cells are oxidizing only glucose (a carbohydrate). -Metabolic rate would then be 10 mL O2/min × 21.1 J/mL O2 = 211 J/min.
subcategory of phenotypic flexibility
Reversible seasonal changes are termed 'life-cycle stages'. In other words, they are cyclically varying phenotypic expressions of trait's adjustments within an individual organism. They are reversible.
Once we measure metabolism... What do we do with it
Wildlife Biologists are interested in... 1. Overall rate of all physiological activities 2. Resource needs- Conservation issues 3. Index of energetic demands from the env
Triacylglycerol vs glycogen
With 1 mol of the triacylglycerol as a starting substrate, a total of 403 mol ATP are generated ... in comparison with the yields of 39 ATP from glycogen
what is polyphenism?
is a related concept which refers to the ability of organisms (specially some arthropods and other invertebrate) to produce a sequence of generations with different discrete phenotypes in the course of a season to accommodate seasonal changes in the environment.
what is developmental plasticity?
is the irreversible variation in the traits of individuals that results from processes during development as a consequence of variation in the environment.
what is Q10 temperature coefficient?
measure of the rate of change of a biological or chemical system as a consequence of increasing the temperature by 10 C.
Resting Metabolic rate (RMR)
metabolic rate associated with minimal unrestrained activity
amount of oxygen used in oxidation processes
option A: closed system respirometry for small animals (find out how much CO2 is produced option B: open system respirometry (animal is in a thermoneutral zone, no effort to be colder or warmer)
Field metabolic rate (FMR)
rate of energy metabolism during normal activity which includes digestion, exposure to temperatures outside thermoneutral zone (TNZ)
Basal Metabolic rate (BMR)
rate of energy metabolism of a post-absorptive state free of physical, thermal, and psychological stressors, in an animal that is not breeding, or growing.
Respiratory quotients
ratio between CO2 formed in metabolism and oxygen used -RQ strongly suggests which conversion factor from Table 7.1 should be used to calculate an animal's metabolic rate from its O2 consumption. Ex. RQ ~ 1.0 suggests use of the carbohydrate factor, 21.1 J/mL O2 RQ ~ 0.7 suggests use of the lipid factor, 19.8 J/mL O2.
what is energetics?
study of E transfer and use within biological systems
what are sustained metabolic rates (SusMR)
time averaged metabolic rates that are measured in free-ranging animals maintaining constant body mass over periods long enough that metabolism is fueled by food intake rather than by transient depletion of energy reserves.
Magnitude and environment
• Magnitude linked to size of organism: small animals perceive environment differently than larger animals • Environments may be extremely stable (e.g.Atacama Desert) or variable on a seasonal, lunar or daily cycle (e.g. Mediterranean environments): variable environments are highly selective of flexibility & tolerance
what do proteins do?
• Form structural components. Ex: Actin (a protein that forms filaments that are one of the major components of the cytoskeleton) • Catalyze & control reactions- Enzymes • Control gene expression. Ex: polymerases • Act as messengers: transmit signals, coordinate processes. Ex: hormones • Transmission and storage of molecules -Proteins underlie all cellular processes -Animals build proteins from combinations of 20 amino acids. The collection of amino acids, with their unique properties of chain length, shape, charge, and polarity, provides cells with the building blocks necessary to construct thousands of different proteins.
Protein Evolution: Change in DNA sequence
• Genomes can be altered by pointmutations, especially by single base deletions & duplications (usually repaired) • More substantially remodeled by recombination events during meiosis, which can result in duplication, deletions and transpositions. • Recombination likely results in changes in physiological performance
what are the fuel sources for glycolysis?
• Glucose is the primary fuel source for glycolysis, but it is stored as glycogen in many tissues, especially muscle and the liver of vertebrates. • Glycogen is often present in the cytoplasm in the form of granules that also contain the enzymes for glycogen synthesis and degradation as well as enzymes that control these processes. • Other sugars, including fructose and galactose, can also enter the glycolytic pathway. Ex. In mammals, the lactose present in milk is hydrolyzed to fructose and glucose.
Anaerobic Metabolism
• Higher vertebrates only use anaerobic pathways to any great extent during short bursts of intense activity (ex. spurts of exercise are needed for prey capture or escape responses, diving). • Why? rapidity of ATP generation, the reaction is entirely in the cell cytoplasm, and nothing need be transported in or out of the cell to support the catabolic reactions. • BUT rapid build-up of end-products, toxic! Ex. end-product (lactate) has to be removed by the liver. • Inefficient, in comparison with aerobic metabolism
environment changes seasonally?
• Intensity of environmental stress • Magnitude & timescales of fluctuations • Energy and resource availability
How does resource availability affect diversity and types of organisms found in specific environments?
• Low resource availability (e.g desert/polar regions): simple communities with short food chains • animals with low metabolic demands • High resource availability (e.g tropical rainforest): diverse and complex communities • highly specialized animals with higher metabolic demand
what are regulators
• Maintain some or all of their internal environment close to the original or normal level, irrespective of changes in external conditions e.g. osmoregulators, thermoregulators (endotherms) & oxyregulators -There is never a perfect animal that fits these definitions - usually a combination of the terms. Emphasizes the animal x environment
what can changes in the DNA sequence lead to
• Subtle changes in enzyme activity & signaling activity • Changes in morphology of protein • Effects on the expression of other proteins -All these can lead to permanent heritable change and produce results at all levels of biological organization
amino acids
• The ATP yields are relatively modest (ex. Alanine 15, glutamate 27) • Important role in structure and function of all animals • Some amino acids that cannot be synthesized, acquired through diet • Animals do not generally store amino acids for future use • Note that where proteins or amino acids are fed into the oxidative cycle there will also be production of bicarbonate and ammonium ions as wastes
physiology is diverse
• There are more than a MILLION different species of animals that live on Earth, each of which has acquired through evolution countless unique and diverse properties • Great diversity of animal body forms and physiological strategies that animals use to cope with their environments • Diversity in adaptation and acclimation makes generalization difficult; diversity among ecotypes
what do the characteristics of an adaptive trait have?
• Trait must vary among individuals • Trait must be heritable - genetic and passed on • Trait must increase fitness (reproductive success)
what are conformers?
• Undergo changes of internal state similar to changes of state imposed externally • Do not attempt to maintain homeostatic condition e.g. osmoconformers, thermoconformers (ectotherms) & oxyconformers
Importance of Protein Variation: Protein Isoforms
• Variants of any one protein 'type': Isoforms have same function but different kinetics • In most animals, multiple variant forms of almost every gene exist • Gives animals a range of options as to which protein it uses (time & space)
what is Adenosine triphosphate (ATP)?
•ATP is the best known phosphagen (high-energy phosphate compounds that mediate energy transfers for all processes in living organisms) • Common currency of energy metabolism for animals, providing the link between energy-yielding and energy-requiring reactions. -anaerobic metabolism (independent of oxygen) -aerobic metabolism (pathways which require oxygen)
size matters/allometry
•Animals vary tremendously in size! 21 orders of magnitude (bacteria to the 100,000kg blue whale) •Size has consequences for structure/function relationships -allometry: study of how various traits change with body size Exs: bones, metabolism
abiotic master factor temperature
•Coined the Abiotic Master Factor in 1971 by JR Brett. •"Temp is arguably the most important abiotic stress that ectothermic organisms experience..." Hochachka and Somero, 1984; Somero, 1997; Stillman and Somero, 2000 •Why is temperature so important? •Tremendous effects on Biochemical Reaction Rates! •Q10 values
