Exam 1 Flashcards
What is Ecology?
The study of 1) an organism’s interactions with their physical and biological environments and 2) how those interactions shape their distribution + abundance.
Why study ecology?
1) concept of limitation: resources are not infinite, need to conserve and protect.
2) Concept of inter-relatedness: between organisms + environment.
5 threats to marine biology
- Fisheries, 2. global climate change, 3. dramatic change in/loss of/alteration of habitat, 4. invasive species, 5. chemical pollution and eutrophication
Reductionist Approach
A scientific approach of learning about something by breaking it into smaller parts and studying those parts.
Temporal Variation can be…
Predictable: seasonal or daily schedules.
Unpredictable: More extreme conditions are less frequent and predictable.
Spatial Variation
Can be on a small scale (forest sunflecks) or large scale (latitudinal variation in solar plexus). Scale of variation is important to the function of an organism.
Experimental Design
- Must be able to replicate.
- Must have random distribution of treat.
- Results found using statistical analysis.
Laboratory Experiments
Most exact regulation of abiotic and biotic factors, vary only factor of interest. Disadvantage in oversimplification of biotic community. Best use in physiological responses in individuals.
Field Experiments
Conducted outdoors, manipulation of abiotic or biotic factors. Disadvantage: methods of exclusion are unlikely to be generated in nature.
Natural Experiments
Uses natural perturbations (ex. tsunami) to disrupt biotic community. Used to follow the trajectory of the perturbation over time. Results can be extrapolated to other communities.
Experimental problems
Correlation does not = causation; sometimes scale is too large to perform (pattern of evolution or spatially), casual factors can’t be independently tested.
Microcosms
replicate essential features of the system in a field or laboratory setting.
4 Categories of Rapid Evolution
- Evolution of trophic links via specialization (ex. Darwin’s finches)
- Evolution of defense (moths)
- Rapid loss of traits in response to absence of interaction (defensive traits in guppies)
- Niche Theory: realized niche constrained by biological interactions among species)
Niche
An organism’s place in environment defined by physiological tolerances and resource requirements.
Force: No-slip condition
Fluid in contact with solid surface doesn’t slip; easily to be moved away from environment closer to the surface and easier to bear closer to the boundary layer.
Force: Drag + Drag resistance
All actions have an equal and opposite reaction. (if force exerts by one body, will also be received by the organism acting against it).
Minimizing strategies: flexibility (reduce area affected), collapsing (holly bush), drag resistance (wider base + buttresses in trees), evolve or develop streamlined bodies.
Force: Pressure
Bernoulli’s principle
Principle of continuity
Bernoulli’s principle: pressure is inversely proportional to velocity.
Force: Lift
Can either maximize (bird wings) or minimize (limpets sticking to rocks)
Flow affects…
- Shape + performance
- exchange processes
- fitness
- distribution of organisms
- transport processes
Scaling
relating body size to an entity or process
Size affects…
Gravity: circulation, movement + locomotion
Surface Area/Volume Ratio: respiration + digestion, water balance, thermoregulation
Allometry
The study of differential growth and biological scaling
Three types of allometric scaling
Isometric: b = 1
Negative: b < 1
Positive: b > 1
(True when measure like dimensions)
Geometric (Isometric) Scaling
Preserve basic shape as size changes
How can animals increase in size without being “all skeleton”?
Animals accept lower safety factor. Experience a decrease in locomotor functions, alter morphology to reduce skeleton stress, or alter chemical composition of skeleton.
Keiber’s Rule
Metabolic rate = M^0.75
Energetic Equivalence
total energy flux of a population invariant with respect to body size.
Global Size Density Relations
Data from literature, densities from any point on the globe.
Local Size Density Relations
All population densities taken from a single region.
Bergmann’s Rule
Organisms tend to be smaller in warmer temperatures than in colder temperatures.
Foraging
Looking for food and eating it whenever found.
Foraging: Natural Selection should aim to maximize…
survival during food shortages + rate of energy gained to allocate growth and reproduction.
Premise of Optimal Foraging Theory
NS acts to leave a higher proportion to foragers with highest net gain of energy.
Two Types of Consumers
Specialist + Generalist
Specialist: Pros + Cons
Pro: Fine-tuned to overcome prey, minimization competition.
Con: vulnerable to prey shortage, no reduction of toxins in prey (if that’s the case), may have long search times.
Generalist: Pros and Cons
Pros: Short search times, diffuse prey toxins, unlikely to starve with broad options of food.
Cons: Need to compete for food, less adapted to overcoming prey defenses.
Patch Model Assumptions
- Prey in distinct/discrete patches, 2. No food intake between patches, 3. Consumer can access food in patch.
Optimality Modeling: advantages, logic, disadvantage
Logic: NS generates behavioral responses that max fitness by balancing benefits against costs.
Advantages: assumptions explicit, generates testable predictions, suggests new hypotheses if model doesn’t fit.
Disadvantages: Behavior is not always optimal.
Elements of Optimality Model
decision variable (pursue prey or not), currency (related to fitness, max rate of energy intake), constraints (intrinsic: organism disadvantage; extrinsic: environmental issues)
Two Ways to Max Foraging
- Time Minimizer: minimize time needed to gain specific amount of energy (ex. snails and barnacles).
- Maximize E if circumstances are not too dangerous (locate + consume highest energy yield)
Search Time (patch foraging)
Greater when more time was spent getting to area of patch (travel time).
Marginal Value Theorem
When an organism chooses to stop foraging due to decrease in prey and travel time.
Reasons for Partial Preference
discrimination error, lack of complete information, prey size variation, simultaneously encounter other prey.
Life Histories
Continuum of ecology from reproductive strategies, dispersals, recruitment
Dispersal
spread of reproductive propagules (seeds/larvae) or individual organisms (juvenile or adult) in space and time.
Life History
Schedule of an organism’s life including: age of maturity, number of reproductive events, allocation of energy to reproduction, number of and span of offspring, life span. Overall: sequence of developmental stages and associated processes (growth, reproduction, dispersal).
4 Life History Strategies
Reproductive, survival, habitat usage, competition with other organisms.
Life history is influenced by…
body plan + lifestyle, evolutionary responses.
Reproductive Strategies
Iteroparous: repeated reproduction
Masting
episodic, synchronous of large seed crops by a population of plants.
Why Masting?
- wind pollination, 2. predator swamping (safety in numbers), 3. environmental forcing (choose when to release seeds via predictions). (Respond to temperature changes from one season to the next).
Semelparous Organisms
Reproduce once
Pros + Cons of Iteroparous vs Semelparous Reproductive Strategies
Iteroparous
Pros: many chances, greater fitness.
Cons: high lifetime investment, less energy for other processes.
Semelparous
Pros: delayed cost of reproduction = more energy for other processes.
Con: Risky, one chance to successfully reproduce and lower fitness.
R Selection
large reproductive investment, large number of offspring, gen. poor competitors.
K Selection
moderate to low reproductive investment, smaller number of offspring, good competitors.
Dispersal Strategies
fragmentation (break off), migration, individuals of a new generation leave actively or passively.
Gen Pop. Significance of Dispersal
Spread genes, keep population from being too large, prevent extinction through gene flow.
Escape Hypothesis
Get away from mortality surrounding parents -> predators, pathogens, competition.
Janzen Connell Dispersal Model
Seeds will survive if they’re moderately dispersed from parents.
Energy Budget
How resources are divided among life history stages or functions.
Life History Strategy
Investment strategy shaped by NS.
Fixed Reproductive Effort
Average fitness of offspring is inversely proportional to the total number of offspring produced.
Size v. Number Tradeoff
Higher number of offspring, smaller in size.
Unitary Aclonal Organisms
Germ cells (reproductive cells) separate from body (somatic) cells; Body form highly determines cell fates, fixed early in embryological development.
Clonal and Modular Organisms
Cell lines not separate. Cell fates not fixed, indeterminate body plan.
Clones
An assemblage of organisms that are genetically identical by descent. Units capable of functioning independently.
Difference between clonal modular and non-modular
Clonal modular grow by repeated iteration of parts; non-modular ex. lizards + aphids.
Genet
Whole organism of one genotype.
Ramet
Clonally produced part of the genet.
Ways Clones are Created
fragmentation, fission (dividing), asexual budding, parthenogenesis (development of unfertilized egg; non-modular), sexual reproduction.
Consequences of Cloning (Positive)
Enables fit genotypes to be inherited intact. Enables rapid, short distance colonization. Reproductive output doesn’t decrease with age. rapid utilization of food resources. Allows polymorphism (specialization of modules for different functions), can survive partial mortality, reduce genotype mortality.
Negative Cloning Consequences
Mutation meltdown (accumulation of deleterious mutations), can’t respond well to environment change, poor long distance colonization, may divide too small (fission), parthenogenic organism may reproduce sterile offspring.
