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81 Cards in this Set

  • Front
  • Back
what is Ecology
Ecology is the scientific study of the relationship between organisms and their enviroment
What types of Experiments are used in Ecology?
Natural, Field, Lab
Define Fitness
An individual is measured by the proportionate contribution it makes to future generations
3 things required for natural selection
1. Off spring resemble parents
2. Variation in traits among members of the population
3. Differential reproductive success tracked to hertiable traits
sum of heredity information carried by the individual
physical expression of a characteristic of an organism, determined by both genetics and environment
unit of material of inhertiance, more specifically a small unit of a DNA molecule, coded for a specific protein to produce on of the many attributes of species
Directional Selection
Mean value of the trait is shifted to one extreme or the other
Stabilizing Selection
favor individuals near the population mean at the expense of the 2 extremes
Disruptive Selection
Occurs when memebers of the population are subjected to different selection pressures.
is a change in gene frequencies within a population over time. Individuals do not evolve, populations do
Relevence of a Spandrel
Is a phenotypic characteristic that evolved as a side effect of a true adaptaion. In terms of evolution the term is a metaphor for characteristics that were orignally side effects and not true adapations to the environment in which they live.
competition among individual species. Limits carrying capacity. Some species require same resources.
competition occurs between memebers of different species.
1. occurs when a resource is in limited supply relative to those using the resource
2. is an interaction that leads to a reduced survival, growth or reproduction due to shared requirements for limited resources.
How do parasites differ from parasitoids?
In parasitoids the host dies, in a parasite the host lives and provides nutrients
Difference between Explotation and Interference competition
1. Occurs when individuals deplete a shared, general resource pool, reducing the average amount available.
2. Involves direct interaction between individuals, where one prevents access to resources by others.
Competitive Exclusion
Complete competitors cannot co-exist. Co-existance is likely when overlap in resources used is limited.
What experiments did Gause do to illustrate the effects of competition? What were the outcomes?
He used p.aur and p.cad and had them grow separately and both did well, but when put together p.aur was the super competitor, and p.caud went nearly extinct, because they were going after the same resources.
Character Displacement
Two species are more different when they occur together then when they occur apart
a in Lotka-Volterra
per capita competitive effect of species 2 on species 1. In the absence of a competitor, species one will grow logistically.
How does resource partitioning reduce competition and increase coexistence?
Think chipmunks in Sierre Nevada. All 4 species limit each others habitats, so competition is reduced and they can coexist.
Israeli cats
competitve effects and natural selection. Size of canine teeth for small cats species that co-occur in Israel. Size is correlated with the size of the prey selected by differnt species. Also shows sexual dimorphism.
Limiting Similarity
Darwin's Finches. When 2 species are separate feed on an overlapping array of seed sizes. When separate possess similar but overlapping beak size. When together one has larger and the other a smaller beak, so they could feed on different seed sizes.
what effects does competition have on individuals
-reduce average individual size
-reduce growth rate
-increase susceptibilty to disease
-modify timing of or number/quality of offspring
-reduce survival
R* Model
-mechanistic model that focuses on ability to respond to resource levels
-the superior competitor is the one that can subsist on the lowest levels of resources, using them down to that level and driving other species to become excluded.
True predators
eat multiple prey, death usually involved; scavengers a special case
eat parts of multiple prey, but usually don't kill the prey
obtain nutrition from a single or alternate hosts, but usually don't kill prey
single prey eaten, and death is always involved
the consumption of all or part of one living organism by another. Complex interaction b/t two or more species.
Characterize the equilibrium behavior using the predator-prey models.
Increase in prey=increase in predator, increase in predator means decrease in prey, decrease in prey means decrease in predator. The cycle continues.
How does herbivory affect the fitness of plants and growth rates?
1. slower gain of C
2. fruit and/or flower abortion
3. reduced reproductive success in subsequent year
How plants defend themselves from herbivory
1. structural defenses: hairy leaves,thorns, and spines
2. contain a variety of chemicals that are not used in basic metabolism of plant cells
Nitrogen based compound
include alkaloids such as morphine, atropine, nicotine, and cyanide.
Terpenoides aka isoprenoids
essential oils, latex, and plant resins (spices or fragrences)
general class of aromatic compounds
Function of these secondary compounds
1. Inhibit digestion
Qualitative Inhibitors
toxic, herbivores avoid consumption. Includes CN, alkaloids such as: nicotine, caffeine, cocaine, morphine, and mescaline (interfere with metabolic pathway)
Plants send signals to herbivories predator
corn and wasp
plants and arthropods
Likely reason for Hare cycle
1. Lots of Hare produce food shortage
2. Weakened Hares not reproducing, very vunerable to predation
3. Intense predation cause rapid decline in # of Hare
4. Predators face food shortage
5. Predators don't reproduce
6. Releases pressure off Hare, and plant growth rebounds
intimate and protracted association between two or more organisms of different species
What types of symbioses exist in nature
parasitic relationships
Meningeal work of deer
Deer eats infected snail while grazing , in deers stomace the larvae leave the snail, puncture the deer's stomach wall, and enter ab membrane and travel via spinal cord to reach spaces surrounding the brain, here they mate and produce eggs, eggs and larvae pass through the bloodsteam to the lungs, where larvae break into air sacs and are coughed up, swallowed and passed out through the feces, snails aquire larvae and the cycle continues.
a relationship between two species in which one species benefits withhout significantly affecting the other
Example: Deer cycle
is a relationship between members of two species that benefits both
a) symbiotic
b) nonsymbiotic
a) individuals coexist and their relationship is obligatory. Atleast one memeber becomes totally dependent on the other.

b)two organisms do not physically go coexist, yet depend on each other for some essential function.
Example of Mutualism
Cows and Bacteria (ruminants)
-the chambers of the stomach contain large populations of bacteria and protozoa that carry out the fermention process
Mycorrhizae and plants
fungi assist the plant with the uptake of nutrients from the soil. In return the plant provides the fungi with carbon, a source of energy.
Acacias and Ants (defense)
Ants live in swollen thorns and live there most of their life and get all the nutrients they need, but when the tree is attacked the ants swarm out and emitt bad odors and attack intruder until it leaves
plants and pollinators (nonsymbiotic)
Feed on pollen and animals carry pollen to other plants of the same species, increases plant fitness, sugar rich nectar
relationship between two species that is beneficial to one, but neutral or of no benefit to the other
Differences between Commensalism, mutualism, and parasitism
1. Comm-one benefits other not helped or hurt
2. Mutualism-both benefit
3. Parasitism-one helped, other hurt sometimes death
what is meant by "apparency" in relation to plant-herbivore interactions
often in monocultures, large, long-lived, chem defenses against generalists and specialist herbivores, defenses such as tannins often greater than 1% of fresh weight of leaf, late successional (trees)
populations benefiting from nonessential interaction
Why and how are environmental science, environmental advocacy, pollution abatement, and conservation biology different or distinct from ecology
Environmental Advocacy is recycling and save the whales. All are focused on a specific environmental problem but ecology does form the scientific framework for all of these pursuits.
light compensation point
depth of water or level of light at which photosynthesis and respiration balance each other
light saturation point
Amount of light at which plants achieve the maximum rate of photosynthesis
C3 pathway
light reaction-chlorophyll traps light energy with in chloroplast cells. Absorption of photon raises E level. Excited molecule not stable and e-'s rapidly return to ground state, releasing the absorbed E. E is transferred to electron transport chain. Make ATP from ADP and NADPH from NADP+

Dark Reaction: RuBP combines with CO2 to form 2 3-PGA and catalyzed by rubisco. Plant converts 3-PGA into energy rich molecule G3P. Synthesis from 3-PGA to G3P uses ATP and NADPH made from light rxn. Some will produce sugars, starches, and other carbons needed and the rest to make new RuBP
C3 drawbacks
Rubisco driving the process of carboxylation also acts as an oxygenase. Rubisco can catalyze the reaction b/t O2 and RuBP. Oxygenation of RuBP results in eventual lost of CO2
C4 pathway
2 types of photosynthetic cells: mesophyll and bundle sheath

CO2 reacts with PEP (MES) catalyzed by PEP carboxylase producing OAA then rapidly to from four carbon malic acid and aspartic acids transported to bundle sheaths, there enzymes breaks down acids to form CO2, in bundle sheath the CO2 is transferred into sugars using the C3 pathway involving RuBP and Rubisco
CAM pathway
like C4 but 2 separate steps, both in mesophyll but at separate times. CAM plants open stomata at night taking CO2 and converting it to malic acid using PEP. During the day closes stomata and converts malic acid to CO2 then fixes in C3 cycle. CAM pathway slow and inefficient
net rate of photosynthesis
mostly grasses native to tropical and subtropical regions and some shrubs characteristic of arid and saline environments. SW north america
Water use effiency
Hot Deserts of the world
Phenotypic Plasticity
ability to change form under different environmental conditions.

In plants: The size of the plant, the ratio of reproductive tissue to vegetative tissue, and even the shape of the leaf may vary widely at differ levels of nutrition, light, moisture
Upper and Lower leaves
Upper: get higher levels of solar radiation and experience higher temps so they are small and thicker and more lobed then those at the bottom that are thinner and larger. This morphology aids in heat loss through convection. The larger thinner leaves at the bottom increase the surface area for capture of light.
importance of mycorrhizae
fungus-root relationship. Plant receives P, and Fungus receives C.
Ecto differ from Endo
Endo-produced internally from high metabolism

Ecto-Obtain heat from enviroment-Low metabolism
Homeotherms differ from Poikilotherms
Homeo-Constant body temp

Poilkilo-Body temp varies
How do poikiliotherms thermoregulate?
Dependant on Environmental Temperatures. Increase in 10 degrees C doubles the rate of metabolism. They have an upper and lower limit that is the operative temperature range
employ both endothermy and ectothermy. Depending on environmental and metabolic needs. Bats, Bees, and Humming birds, fish. Physiological.
What role does Torpor play in energy conservation in homeotherms?
reduces metabolic costs during pds of inactivity. Daily Topor is the dropping of body temp to approximately ambient temp for a part of each day regardless of season. Ex: Humming birds
what are the problems and adaptations associated with obtaining, keeping, and getting rid of water in the terrestrial, aquatic, and marine environments?
Fresh water = Hyperosmotic
Higher salt [] in bodies than in water. Dont want to lose or gain water

Salt water=hypoosmotic- lower salt [] than water, makes them dehydrate, osmosis draws water out of body to environment

Terrestial animals have 3 major means of gaining water and solutes: directly by drinking and eating, and indirectly by producing metabolic water in the process of respiration. animals in arrid regions may reduce water loss by becoming nocturnal, producing highly concentrated urine and feces
Why do animals often father in groups for foraging or defense
Strength in numbers. Example: Zebras when together you cant tell apart
Typically short lived
competitive species with stable populations of long-lived individuals.
Density dependant
factors that have an influence on individuals in a population that vary with the density of the population.
Density Independant
factors that have an influence on individuals in a population that do not vary with the density of that population

Ex: Hurricane, Tree falls
net reproductive rate
average number of female offspring produced by an average female during her lifetime