Exam 1 Study Guide
∙ What is Ecology?
o Abiotic Environment
o Biotic Environment
∙ Ecology is divided into different hierarchies
o Organismal ecology
o Population ecology
o Community ecology
o Ecosystem ecology
o Ecosphere or biosphere
∙ Why is it important to study Evolution with Ecology?
o Natural resource management
o Environmental Problems
o Human Health
∙ How did Darwin develop the Theory of Evolution by Natural Selection? o Observations
o Logical Arguments
o Darwin’s ideas
Descent with modification
∙ Natural Selection in a nutshell
o More individuals are born than can make it
Therefore, there is a struggle for existence
o Individuals vary in traits that affect survival and reproduction The individuals with higher fitness end up being the ones that reproduce
o Successful traits are passed from parent to offspring
Attributes of a species can change over time.
∙ Drawbacks to Darwin’s Ideas
o Inheritance wasn’t fully understood
o The concept of the gene wasn’t discovered
o Blended inheritance wasn’t discovered: the sharing of phenotypic characters between both parents in the offspring
It was thought that the genetic material of offspring was held to be a uniform blend of that of the parents. Don't forget about the age old question of consensus model vs conflict model
o Genetic makeup
o Observable characteristics
o Only acts on the phenotype since it is observable, BUT there will only be an evolutionary response if there is a genetic basis to the variation in phenotype
o Selections occurs when a particular genotype does not survive or reproduce in the same proportion as others
o Selection Coefficient (s)
∙ Types of Selection
∙ The Red Queen Hypothesis
∙ What is Evolution?
o Changes in allele frequency
∙ Allele frequencies change over time
o Selection is only one mechanism that can drive a change in allele frequencies
∙ The Hardy-Weinberg Equilibrium
o Know how to use the equation
o Know how to figure out if the population is in equilibrium o “null model” Don't forget about the age old question of biol3110
o Check out the videos on blackboard in the “Hardy-Weinberg videos” folder
∙ The five agents or mechanisms of evolutionary change o Mutation Don't forget about the age old question of cob 241 jmu
o Gene Flow
o Non-Random Mating
o Genetic Drift
∙ Persistent selection can produce substantial changes in allele frequencies over time
∙ Darwinian Fitness
∙ How do adaptations arise?
o Via natural selection
∙ The evolution of resistance in pathogens and pests
o Antibiotic-resistant infections
∙ Other mechanisms driving evolution
o Genetic Drift: the effect of population size If you want to learn more check out keystone ecu
Strong when populations are small
o Gene Flow via dispersal of individuals
o Mutation Pressure
o Non-Random Mating
∙ Ecological interactions promote evolutionary change in populations
∙ How do environmental factors limit growth and survival?
Resources The inorganic materials or energy
organisms require for existence
conditions that affect growth and survival
∙ How do organisms cope with environmental variation? o All organisms must survive and reproduce or they must move to an environment where they can survive and reproduce
o Two types or responses:
∙ Metabolic Avoidance
∙ The fitness of phenotypes also depends in the environment. ∙ What is fitness? If you want to learn more check out basic energy concepts
∙ Shelford’s Law of Tolerance
∙ What s homeostasis?
∙ Know about how evolution shapes tolerance curves
∙ Environmental conditions chance over time
o This can be either predicable or unpredictable.
∙ The Principle of Allocation
∙ Evolutionary Trade-Offs
o The benefits and costs of being a cheetah
∙ What works in one environment may not work in another
∙ What types of adaptations have evolved to avoid harsh conditions? ∙ How to physiological adaptations alter the tolerance limits of organisms?
∙ Interactions between the physical environment and phenotype affect fitness and subsequent evolutionary adaptation.
∙ There are upper and lower limits to the environmental conditions an organism can tolerate.
∙ Adaptations necessitate trade-offs in the performance of organisms. ∙ Organisms deal with the changing environments via avoidance and adaptive responses.
∙ How do physiological adaptations alter and organism’s tolerance limits?
∙ Two possibilities for physiological adaptations: If you want to learn more check out mat 182
o Tolerance to internal conditions
o Mechanisms that counteract the external challenge- internal homeostasis is maintained
∙ Why is temperature and water availability universally important? ∙ Temperature affects the rates of all chemical reactions o Magnitude can be measured by Q₁₀ which is the increase in the reaction rate for each 10°C increase in temperature.
∙ What happens when temperature is to high?
o Denaturation of proteins and DNA
∙ What happens when temperature is to low?
o Freezing of intracellular water
∙ The physical mechanisms of heat transfer determine temperature adaptations
o Heat can be gain or lost by:
Evaporation of water
o Htotal = Hm ± Hc ± Hcv ± Hr ± He
∙ Thermoregulation of Homeotherms
o Ways to thermoregulate:
o Countercurrent heat exchange
∙ Thermal adaptations in plants
∙ Adaptations to Water Stress
o φtotal = φosmosis + φpressure + φmatric
∙ Plant adaptations to life on land
∙ The photosynthesis dilemma
∙ C3 vs. C4 photosynthesis
∙ What are the benefits and trade-offs of C4 and C3 plants?
∙ What are Osmoconformers?
∙ What are Osmoregulators?
∙ Some desert animals can survive solely on the water produced by respiration.
o C6H12O6 + 6O2 6CO2 + 6H2O
∙ Excretion of nitrogenous waste entails water loss
∙ Organisms have a variety of physiological and behavior adaptations to deal with in the environments.
∙ Physiological adaptations are especially important for organisms that cannot undergo inactivity or migration
∙ Biochemical reactions are limited by temperature
∙ What determines species distributions?
o Physical environment
o Biotic interactions
∙ What is Ecological Filtering?
o Abiotic filters
o Biotic filters
∙ Abiotic factors determining the geographic range
∙ What determines a species distribution?
∙ What are the fundamental types of terrestrial communities? ∙ Altitudinal variation in temperature
∙ Mean annual temperature is driven by the angle of the sun’s rays o 90° at equator so the radiation is more intense
o shallower angles at higher latitudes
∙ The tilt of the Earth’s axis relative to the sun creates the seasons. ∙ Everywhere on the planet receives the same total amount of daylight ∙ The further from the equator, the more seasonal the environment ∙ Latitudinal variation on precipitation
o Driven by the global air circulation
o Circulation cells:
∙ Local variation in precipitation is driven by major landscape features o Like rain shadows on the leeward side of mountains
∙ Climate is the main determinant of plant community type ∙ Biome
o A fundamental type of terrestrial community
o Linked to climate patterns ∙ Specific Biomes
o Tropical Rainforest
o Tropical Savanna
o Mediterranean Shrubland o Temperate Grassland
o Temperate Deciduous Forest o Conifer Forest
∙ The distribution of species depends on evolutionary history o Geological history
o Historical shifts in climate
o Phylogenetic history
∙ The tolerance level of species can expand
∙ Biogeographical Realm: a fundamental type of terrestrial community ∙ Biomes vs. Flora/Fauna
∙ 7 major water reservoirs:
∙ What are some important physical factors in aquatic systems? o Oxygen concentration
o Limited nitrogen and phosphorus availability
o Thermal buffering
o Light availability
o Changes in wavelength with depth
∙ Freshwater ecosystems
o Lentic Systems: not moving
Lakes and ponds
o Lotic Systems: moving
Streams and Rivers
∙ Terrestrial and Aquatic Ecosystems are connected
o Autochthonus sources
o Allochthonus sources
∙ River continuum concept
∙ Lentic Ecosystems
o Shallow lake and pond zones
o Deep lake zones
∙ Biological carbon pump and ocean acidification