Exam 1 Study Guide

Why is it important to study Evolution with Ecology?

BSC 385

∙ 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

∙ Teleology

∙ How did Darwin develop the Theory of Evolution by Natural Selection? o Observations

o Logical Arguments

o Conclusions

o Mechanism

o Darwin’s ideas

 Descent with modification

 Common ancestry

∙ 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

How did Darwin develop the Theory of Evolution by Natural Selection?

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

∙ Genotype

o Genetic makeup

∙ Phenotype

o Observable characteristics

∙ Selection

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

How do environmental factors limit growth and survival?

o Selection Coefficient (s)

∙ Types of Selection

o Stabilizing

o Directional

o Disruptive

∙ 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

o Selection

∙ 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?

Physical  

Resources The inorganic  materials or  energy  

organisms  require for  existence

Physical  

(Abiotic)  

Factors

Physical  

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:

 Avoidance

∙ Migration

∙ Metabolic Avoidance

o Hibernation

 Adaptation

∙ 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:

 Conduction

 Radiation

 Convection

 Evaporation of water

 Metabolism

o Htotal = Hm ± Hc ± Hcv ± Hr ± He

∙ Thermoregulation of Homeotherms

o Ways to thermoregulate:

 Shivering thermogenesis

 Non-Shivering thermogenesis

 Sweating

 Panting

 Fur

 Blubber

 Feathers

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

o Disturbance

∙ Abiotic factors determining the geographic range

o Climate

 Temperature

 Precipitation

o Soils

∙ 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:

 Hadley Cell

 Ferrel Cell

 Polar Cell

∙ 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 Desert

o Mediterranean Shrubland o Temperate Grassland

o Temperate Deciduous Forest o Conifer Forest

o Tundra

∙ 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:

o atmosphere

o ice

o oceans

o lakes

o rivers

o groundwater

o soil

∙ What are some important physical factors in aquatic systems? o Oxygen concentration

o Salinity

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