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242 Cards in this Set
- Front
- Back
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What is population ecology
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study of the interactions involving populations
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what determines population ecology distirution and abundance
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changes in population size
Growth (texts focus on this) |
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where the the origins of population ecology come from
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developed as part of a number of applied fields including fisheries, wildlife, and pest control
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what does population ecology emphasize
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development and testing of mathematical models of population processed
-determine sustainable harvest levels -minimum viable population sized for threatened and endangered pops -control methods to most effectively slow growth of pest pops |
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what is a population
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a group of individuals of the same species in a particular area
-assumed the group is interbreeding -area can have natural boundaries -area may be defined arbitrarily like a county or state |
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what are two types of geographic range boundaries
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-geographic barries such as mountains or oceans
-environmental conditions beyond tolerance limit of species (ex. red maple doesn't grow too far north due to cold or too west due to dryness) (((and has ocean as eastern and southern boundary)))) |
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what is a tolerance limit
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minimum and maximum levels beyond which a particular species cannot survive or reproduce
bell shaped curve: -zone of intolerance -zone of physiological stress -optimal range -zone of physiological stress -zone of intolerance |
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what is the zone of intolerance
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level beyond which a species can survive or reproduce
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when talking about tolerance limits, this age exhibits tolerance limits that are more critical
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tolerance limits are more critical for the young than for the adults
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what is shelford's law of tolerance
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for an organism to succeed, conditions must remain within tolerance range of the organism and if any condition exceeds the min or max tolerance, it will fail to thrive
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what is a subpopulation
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within a geographical range of a species there is a smaller distinct population
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what is a metapopulation
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collective of local subpopulations
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animals need to adapt in a few select categories:
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obtaining food
obtaining oxygen thermal regulation water balance |
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what is a heterotroph
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animals that get food from the environment because they can't make it themselves
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what are the 4 types of heterotrophs
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herbivores (eat plants)
carnivores (eat animals) omnivores (eat plants and animals) detritivores (eat dead/decaying matter) |
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what are some obstacles of herbivores
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-animals are high in fat and protein
-the plants they eat are low in protein and high in carbon -plant parts vary in chemical content -plants have lots of carbon compared to nitrogen 50:1 where as animals have less carbon to nitrogen 10:1 |
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what are the different types of herbivores
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-grazers (eat leafy material, especially grass)
-browsers (feed on woody material) -granivores (eat seeds) -frugivores (eat fruit) |
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what is a grazer
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herbivore that feeds on leafy material, especially grass
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what is a browzer
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herbivore that feeds mostly on woody material
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what is a granivore
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a herbivore that eats seeds
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what is a frugivore
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herbivore that eats fruit
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nutritionally what is wood/bark composed of
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chemically protected
carbs cellulose |
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nutritionally what is fruit and phloem sap composed of
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carbs
sucrose low protein |
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nutritionally what are leaves composed of
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cellulose
sucrose enzymes |
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nutritionally what are seeds composed of
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starches or oils
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describe the monkey example where animals face challenges in getting nutrients
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monkeys limit leaf eating because of alkaloid content which makes them sick
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what is bad about having plants as food
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cellulose in cell walls are impossible for eukaryotes to digest
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having plants as food is hard because it is impossible for eukaryotes to digest, but what other plant component is also hard to disgest
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lignin
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what is the difference in animals digesting starch and cellulose
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animals have enzymes that can break starch, but they don't have enzymes to break bonds and digest cellulose
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which heterotrophs have a symbiotic relationship with bacteria and protozoa
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grazers and browsers because the bacteria and protozoa break down cellulose and lignin
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if you're an animal that eats plants and you don't have a symbiotic relationship with bacteria or protozoa, what do you do?
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need:
chewing cooking gizzards to accomplish same task |
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what is fermintation
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break down cellulose in absence of oxygen
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what is breaking down cellulose in the absence of oxygen
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fermintation
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how do wood beetles break down cellulose
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fungi in gut
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where do ruminants (cattle/deer) digest cellulose
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in foregut=rumen
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describe the pathway of breaking down cellulose in ruminants
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graze, eat, swallow, rumen (with bacteria), regurgitate, chew cud, swallow, if broken down goes to reticulum but if not goes back to rumen
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what do bacteria do in ruminants
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help in breakdown and produce amino acids and vitamins for cows
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describe the digestive system of non-ruminants
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have bacteria in hind gut
single chamber stomach long intestines to increase SA for absorption slows passage to increase absorption convoluted caecum where anaerobic digestion takes place |
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what is coprophagy
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ingesting fecal material to ensure a more thorough digestion
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what is the term used for ingesting fecal material
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coprophagy, ensures more thorough digestion
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what are the positive outcomes of coprophagy
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provides bacterially synthesized B vitamins and gives it a better use for protein... ensure more thorough digestion of plant material
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which is more effective in digestion, a ruminant or nonruminant
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ruminant
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what do birds have to help digest
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crop (reservoir for food)
gizzard (grinding organ, may eat small pebbles or gravel and grit to help digest seeds) |
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the highest quality of plant food has this
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high nitrogen content
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where is the highest quality of plant food high in nitrogen found
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in growing tips, new leaves and buds
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does nitrogen increase or decrease as leaves mature
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decreases
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how have herbivores adapted to consume the highest quality of plant food
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eat high in nitrogen plants,
-do this by eating early growing plants before leaves mature -herbivores give birth at start of growing season |
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what are the positive outcomes of coprophagy
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provides bacterially synthesized B vitamins and gives it a better use for protein... ensure more thorough digestion of plant material
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which is more effective in digestion, a ruminant or nonruminant
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ruminant
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what do birds have to help digest
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crop (reservoir for food)
gizzard (grinding organ, may eat small pebbles or gravel and grit to help digest seeds) |
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the highest quality of plant food has this
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high nitrogen content
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where is the highest quality of plant food high in nitrogen found
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in growing tips, new leaves and buds
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does nitrogen increase or decrease as leaves mature
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decreases
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how have herbivores adapted to consume the highest quality of plant food
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eat high in nitrogen plants,
-do this by eating early growing plants before leaves mature -herbivores give birth at start of growing season |
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what are some ways that herbivores detect nitrogen rich plants
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taste
odor |
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how does mineral availability affect animal growth and reproduction
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mineral availability inflences distribution, behavior, and physiology of animals
-ex: elephants most frequently found at watering holes with high sodium content |
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what minerals are needed for adequate antler and horn growth in deer
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magnesium and calcium
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what is the most unavailable mineral in nature
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sodium
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herbivores are _____limited and have wastes really high in ____
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nitrogen
carbon |
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carnivores are _____ limited and have wastes really high in _____
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carbon
nitrogen |
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in carnivores where does all the protein and nitrogen come from
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muscle protein
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describe the digestive tract of carnivores
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caecum is small, small intestine is small, and nutrients are more readily absorbed
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what is more nutritious, eating animals or plants
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animals
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what is an obstacle carnivores face in eating other animals are food
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they need to catch animals to eat
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as animals increase in size, their volume
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decreases
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how do single celled organisms get oxygen across body
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diffusion
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when an animal increases its size, what is the problem?
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oxygen transport is need to get oxygen to body parts
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how do birds efficiently get oxygen
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air sacks, series of constant steady stream of fresh air
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how to fish efficiently get oxygen
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unidirectional flow of oxygen, but the concentration of oxygen is low so they use counter-current exchange
-in mouth, out gills, oxygen counters to water flow |
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what is homeostasis
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maintenance of relatively constant internal environment in a varying external environment
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what is negative feedback
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controlling due to loss or gain or a property
ex: thermostat kicks on if air temp gets cool, turns off when air temp reaches a certain point |
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what is a homeostatic plateau
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limited range of tolerance rather than one set point
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what is a voluntary mechanism used if the body is too hot
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move to shade or slow activity
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what is an involuntary mechanism used if the body is too hot
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sweat
blood rises to skin surface |
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what is a voluntary mechanism used if the body is too cold
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increase activity
seek shelter or sunlight burrow/huddle/hibernate |
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what is an involuntary mechanism used if the body is too cold
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muscle shivering generates heat
skin blood vessels constrict and reduces heat loss |
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how does the body core exchange heat with surface area
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by conduction
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what is convection
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transfer of heat from solid to moving liquid/air
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what is conduction
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transfer of heat from solid to solid
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what is radiation
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emission of electromagnetic energy
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what is evaporation
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transfer of heat from liquid to vapor
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what are some structures that reduce heat loss in animals
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fur, feathers, fat
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what are the 3 groups of thermoregulators
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Homeotherms
Poikioltherms Heterotherms |
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what is a homeotherm
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keep a relative constant temperature
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what is a poikilotherm
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has variable temperatures
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what is a heterotherms
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use both endo and ecto- thermy
ex: bats, beeds, hummingbirds |
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what is endothermy
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internal heat production
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what is ectothermy
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gain heat from external environment
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in poikilotherms, as temperatures decrease what happens
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they loose heat rapidly to the environment
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if you increase the body temperature in a poikilotherm, what happens to its metabolic rate
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metabolic rate increases
*double metabolic rate with every 10 degree Celsius increase |
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what is the Q10 rule
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in poikilotherms, as you increase the temperature every 10 degress celsius, you double the metabolic rate
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so if you're a poikilotherm, you temperature ranges daily. what time of the day is your body temp most constant
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at night temps are fairly consistent, during day your body temperature will range
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how to poikilotherms behaviorally thermoregulate their body temps
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move! shade if hot, rock if cool
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if you're a poikilotherm and your metabolic rate increases, your gamete production does this
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increases
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do poikilotherms use aerobic or anaerobic respiration during normal activities
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aerobic respiration
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do poikilotherms use aerobic or anaerobic respiration during times of stress
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anaerobic respiration
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what is an advantage to being an aquatic poikilotherm
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they have the same temperature of the water, and the water is thermally stable. poikilotherms adjust seasonally to changing temps by acclimation
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what types of animals have a thermoneutral zone
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endotherms/homeotherms
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how do homeotherms escape thermal restraints of the environment
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efficient cardio and respiratory system allows high level of aerobic respiration
they generate energy rapidly have insulation such as fur, fat, and feathers to help regulate heat exchange |
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which organism looses heat faster, a large or small homeotherm
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small homeotherm looses heat faster
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what limits body size in ectotherms
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SA/V controls the uptake of heat
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which has a lower caloric intake, ecto or endo therms
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ecto
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what is topor
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decrease in body temp to ambient temp for part of each day.. helps conserve energy
ex: hibernation is a long seasonal topor |
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what are some unique physiological means for thermal balance
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storing body heat and release it to environment when the environmental temperature decreases
glycerol in cells to prevent freezing in fish and some insects and frogs camel has fur color of sand to reflect sunlight |
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what is countercurrent heat exchange
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preventing a loss of heat by having interconnecting capillaries so that blood doesn't cool off when returning back to body in extremities
ex: porpoises |
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what happens to body temp as capillaries are most distant from the body core
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body temp decreases with increasing distance of capillaries from body core
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how is countercurrent exchange used for the cooling of organisms
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use shunt mechanism to keep cold from moving up legs of birds standing on ice
keep brain cool by expiring water vapor, cooling blood that travels through nasal passage to brain which cools it (antelopes) |
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what is population abundance
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the number of individuals in a population
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what is population density
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the number of individuals per unit area or per unit volume
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what is the equation for population abundance
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density x area
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what are the 3 types of spatial distribution of organisms
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random
uniform clumped |
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what is random spatial distribution
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nutritional needs met everywhere
ex: dandelion |
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what is uniform spatial distribution
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chemicals or toxins produced prevents closeness and will distribute only as far as won't be harmed
ex: creosote bush |
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what is clumped spatial distribution
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resources are not homogeneous, there are pockets of resources
ex: elephants at a water hole |
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what is countercurrent heat exchange
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preventing a loss of heat by having interconnecting capillaries so that blood doesn't cool off when returning back to body in extremities
ex: porpoises |
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what happens to body temp as capillaries are most distant from the body core
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body temp decreases with increasing distance of capillaries from body core
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how is countercurrent exchange used for the cooling of organisms
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use shunt mechanism to keep cold from moving up legs of birds standing on ice
keep brain cool by expiring water vapor, cooling blood that travels through nasal passage to brain which cools it (antelopes) |
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what is population abundance
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the number of individuals in a population
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what is population density
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the number of individuals per unit area or per unit volume
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what is the equation for population abundance
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density x area
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what are the 3 types of spatial distribution of organisms
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random
uniform clumped |
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what is random spatial distribution
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nutritional needs met everywhere
ex: dandelion |
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what is uniform spatial distribution
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chemicals or toxins produced prevents closeness and will distribute only as far as won't be harmed
ex: creosote bush |
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what is clumped spatial distribution
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resources are not homogeneous, there are pockets of resources
ex: elephants at a water hole |
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we see 3 patterns of spatial distribution, but what is another characteristic of patten we can see?
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patterns within patterns
-see uniform dist -see clumped under uniform dist |
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how do you measure population densities
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count
sample subset mark and recapture |
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what are quadrat estimates
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counting the density of a population by dividing area of interest into subunits called quadrats
most conveniently applied to small sedentary orgs that are easily counted and unlikely to move |
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how do you calculate a population using quadrats
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tsum up the number of idividuals in each quadrat divided by the # of quadrats
multiply that number by the area sampled |
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how do you calculate marked and recaptured way
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take the number of individuals caught at censuing and multiply by the TOTAL number of caught individuals caught 2nd time
divide by the number of MARKED individuals at censusing |
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what determines population density
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limiting factor= temp food water shelter
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what is demography
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the statistical study of populations
helps predict how population sizes will change in the future |
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what is a cohort
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group of organisms that are typically all born in same year
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what is birth rate or fecundity
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number of offspring born in a standard time
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what is death rate or mortality
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number of individuals that die in that period
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what are the challenges of using a cohort
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having to determine age
done by physical structures such as feather morphology or fur colors, tress and fish show plasticity in growth by rings |
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what does a growing population's age pyramid look like
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triangle
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what does a declining population's age pyramid look like?
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rectangle smaller at bottom
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what does a stable population's age pyramid look like
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rectangle smaller at top
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what does an exponential growth curve look like
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j-shaped
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what does an exponential growth curve assume
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unlimited resources
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as population size increases, availability of resources:
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decreases
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when birth rate = death rate, what is the population doing?
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population size is not increasing or decreasing, it is constant
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what is the logistic growth model
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it is a model used to show population growth while accounting for carrying capacity(K)
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as a population approaches its carrying capacity (K), the growth rate does this:
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slows, because of limiting resources
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as N approaches K, what does the growth rate do?
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slows down
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when does N=K
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when growth rate reaches 0
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if N exceeds K, what happens
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growth becomes negative
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what is the shape of the logistic growth model curve
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sigmoidal
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what is K/2
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inflection point where rate stops increasing and begins to decrease
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what is carrying capacity (K)
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the max # of individuals that an area can support
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when comparing a logistic growth model to a real population, what do we see
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doesn't follow patter
oscillations occur around K a lag effect is seen |
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what are density dependent factors
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density causes increased mortality or decreased natality at higher densities
effect is stronger as density increases |
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what are density independent factors
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density is independent of population size
effect is the same regardless of density most density independent factors are aspects of the external environment |
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what is K/2
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inflection point where rate stops increasing and begins to decrease
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what is carrying capacity (K)
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the max # of individuals that an area can support
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when comparing a logistic growth model to a real population, what do we see
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doesn't follow patter
oscillations occur around K a lag effect is seen |
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what are density dependent factors
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density causes increased mortality or decreased natality at higher densities
effect is stronger as density increases |
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what are density independent factors
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density is independent of population size
effect is the same regardless of density most density independent factors are aspects of the external environment |
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what is intraspecific competition
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competition where individuals use a common resource that is in short supply relative to demand
competition among members of the same species |
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what are two types of intraspecific competition
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scramble and contest
scramble: negative effect of competition-repression of growth or reproduction-is spread evenly among individuals contest: negative effect of competition is not spread evenly among all individuals (some win contest) |
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what is scramble competition
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negative effect of competition is spread evenly among individuals (repression of growth or reproduction)
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what is contest competition
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negative effect of competition is not spread evenly among all individuals equally (some individuals win contest)
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what are the two main mechanisms of intraspecific competition
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exploitation and interference
exploitation: no direct interaction, depression of resource levels by presence of consumption interference: direct interaction, one individual prevents other from occupying a habitat or accessing resources within it |
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what is intraspecific exploitation
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competition where individuals use a common resource that is in short supply relative to demand and there is no direct interaction of organisms.... depression of resource levels by presence and consumption
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what is intraspecific interference
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competition where individuals use a common resource that is in short supply relative to demand where there is direct interaction.... one individual prevents other from occupying a habitat or accessing resources within it
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why is high density stressful to organisms
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-trigger hormonal changes
:suppress growth :curtail reproduction :delay sexual activity -suppress immune system :increase mortality rate -increase mortality of fetal stage young and cause inadequate lactation -pheromone production encourage or inhibit reproduction |
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what usually happens with plants when there is crowding
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"self thinning" occurs and remaining individuals will respond with increased growth
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what is the definition of life history
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pattern of growth, development, and reproduction
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what are some trade offs because of resource limits
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use energy for growth or reproduction
have many small offspring or few large with greater parental care reproduce early or late |
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which grows faster: a reproducing or non-reproducing individual
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non-reproducing individual grows faster
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if you spend more energy to reproduction, what is the consequence
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less energy an individual can put towards their own growth and maintenance
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what are 2 types of parental care species
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altricial and precocial
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what are altricial species
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they require nourishment, born helpless, need parental care
(humans, mice, robins) |
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what are precocial species
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they are relatively mature and mobile at birth, and they forage for themselves, less parental care needed
(chicken, cows, deer) |
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what are two approaches for reproduction
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semelparous and iteroparous
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what is semelparous
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investing all energy into growth and development
energy storage followed by a single suicidal bout of reproductive effort many offspring (insects, salmon, many plants) |
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what is iteroparous
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invest less amount of energy into reproduction more than once during life time
few offspring most vertebrates, some plants |
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what is fecundity
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# of offspring in a single reproductive effort
(varies from species to species) (can depend on age or size) |
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what is indeterminate growth
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species that continue to grow throughout their life (produce more offspring as they age)
ex: perennial plants, many poikilotherms |
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what is r-and K-selection
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classify environments (species habitats) based on temporal variability
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what are r-stategists
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high population growth rate with colonization of new or disturbed habitats
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what are K-stategists
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efficient resource use, maintain population at or near carrying capacity
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describe characteristics of r-selection
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rate of increase: high
competitive: not favored development: rapid reproduction: early body size: small reproduction: small, semelparity offspring: many, small |
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describe characteristics of k-selection
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rate of increase: low
competitive: favored development: slow reproduction: late body size: large reproduction: repeated, iteroparity offspring: few, large |
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what are two variables that are most important at exerting selective pressures on plants
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intensity of disturbance
intensity of stress |
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what are the 4 environmental extremes of plant life histories
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low disturbance low stress
low disturbance high stress high disturbance low stress high disturbance high stress (not a viable option for plants) |
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what are ruderals in plant life histories
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in plant life histories, they are highly disturbed habitats, plants grow rapidly and reproduce quickly, and they are short lived
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what are stress tolerant in plant life histories
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resources are limited
grow slowly to conserve resources |
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what is competitive in plant life histories
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low disturbance, low stress
grow well, but eventually compete with others for resrouces |
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what are the 4 basic processes that change the population size
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birth
death immigration emigration |
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what is the equation for growth
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growth= births-deaths
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what is the problem of having a non-linear graph
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rate changes with time
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when looking at a population size, when r>0 what happens
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we see exponential growth
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when looking at population size, when r=0 what happens
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no change in population growth
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when looking at population size, when r<0 what happens
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decline in population
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what are life tables
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used to examine mortality and survival within a population... are an age specific account of mortality
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cohort
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group of individuals born in the same period of time
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looking at life tables, what is x?
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age at beginning of interval
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what does nx mean in life table
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number of survivors at start of age x
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what does lx mean in life table
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probability at birth of surviving to age interval x.... nx/no
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what does dx mean in life table
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number of dying during age interval x to x+1.... no-n1, n1-n2
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what does qx mean in life table
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age specific mortality rate
dx/nx d0/n0 d1/n1 |
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what are the 2 types of life tables
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cohort and time specific
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what is a cohort life table
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follows a single cohort of individuals from birth till all have died
can be difficult if species is long lived |
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what is a time specific life table
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constructed from current mortality rates by age
cohorts sampled simultaneously and it is assumed that age specific mortality is constant over time |
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what is type 1 in a survivorship curve and what does it look like
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humans and other mammals where they have a high chance or survival as young, but die as they get older. starts high and ends low
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what is type 2 in a survivorship curve and what does it look like
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adult birds, rodents, reptiles, and many perenial plants
linear line going from top to bottom |
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what is type 3 in a survivorship curve and what does it look like
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oysters, fish, invertebrates, trees
lots of offspring, where there is a high rate of death in young |
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what is crude birth rate and what does it not take into account
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# of births per 1000 individuals
doesn't take into account age or sex of individuals |
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what is bx in life table
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specific birth rates
-only applies to females |
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what is lxbx in life talbe
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mean number of females born to a female in each age class
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in life table, if R<1 what does it mean
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females are not replacing themselves
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in life talbe if R>1 what does it mean
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females are more than replacing themselves
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what is the net reproductive rate in life tables
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Ro. mean number of female offspring produced per female in her lifetime... sum of lxbx
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what is sx in life table
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age specific survival rate.
1-qx |
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how do you figure out numbers of individuals in life table from year 0
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take # of population in year(x) and multiply by corresponding sx
to find top number, take b1xfound number + b2xfound number |
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in a population projection table, age dristibution will _____ even though population continues to increase
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stabilize
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what is the finite multiplication rate in population projection tables
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shows whether or not population is increasing, decreasing, or remaining constant
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exponential growth is also known as this
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geometric growth
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what is geometric growth
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periodic increase or decrease in a population
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what can lead to population extinction
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reduction of birth rate or increasing death rate
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what is competition
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use/defense of a resource by one individual that reduces the availability of that resource to others
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what are the 6 types of interspecific competitions
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consumption
pre-emption overgrowth chemical interaction territorial encounter |
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how do we detect competition
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resources of organisms must overlap
resource must be limiting to both orgs negative effect to at least one org |
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in barnacle species distribution, what are the patterns
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balanus is larger barnacle found in lower intertidal
chthamalus is small barnacle found in higher intertidal |
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in barnacle species distribution, what were the conclusions of the experiment
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for chthamalus, removing balanus increased downslope survivorship and dist
for balanus, removing thais increased downslop survivorship and dist absence of competitors and predators produced no change in upper level distributions |
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what are the differences in the logistic growth curve and the lotka-volterra growth curve
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logistic is exponential growth
lotka-volterra is sigmoidal |
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what are alpha and beta in lotka-volterra competition model
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competition coefficients, measure effect of one species on the population growth of the other
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if competition coefficient is less than 1, what kind of competition is more deleterious
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intraspecific
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if competition coefficient is = to 1, what kind of competition is more deleterious
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they are equal
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if competition coefficient is greater than 1, what kind of competition is more deleterious
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interspecific
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in lotka-volterra competition graphs, there is no equilibrium of 2 species unless....
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their zero isoclines cross eachother
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what is the competitive exclusion principle
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2 species can't coexist if they share a single limiting resource
dominant competitor will force out subdominant |
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what is competitive release
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when dominant competitor is removed, it allows subdominants to exist in an area
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what is an ecological niche
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range of many conditions and resource qualities within which an organism can persist
an organism's place in an ecosystem total set of environmental factors that determine species dist |
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what is a fundamental niche
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conditions where an organism could exist
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what is a realized niche
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conditions where an organism does exist
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what are factors that influence competition
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temporal heterogeneity
spatial heterogeneity |
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what is temporal heterogeneity
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change in habitat may shift competitive advantage from one competitor to another
seasonal changes in temp or rain can favor a species change in habitat due to age of habitat can alter relationships |
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what is spatial heterogeneity
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gradients (clines) can change competitive outcomes
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how can we see coexistence of species in same habitat
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we see niche partitioning
competitors alter resource requirements so it minimizes overlap and thus competition |
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what is resource partitioning
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species partition feeding by changing habitat or items eaten to allow them to coexist with little competition
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