ch. 51 review matching: a.classical conditioning b.operant conditioning c.habituation d.fixed action...
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Ch. 51 Review
Matching:A. Classical conditioningB. Operant conditioningC. HabituationD. Fixed action patternE. Imprinting
1.Birds exposed to a full song in a critical period cause development of the same song2.Prairie dogs who live near hiking trails do not give alarm calls every time a person walks by3.Your dog learns to shake hands with you when you hold out your hand after being rewarded with treats4.A rat learns how to get through a maze when it is rewarded with a treat, but never obtains food if it makes a mistake5.A baby duck runs for cover when an object is thrown over its head, but stops running after many trials
Ch. 53 Warm-Up
1. Sketch an exponential population growth curve and a logistic population growth curve.
2. What is an ecological footprint?
3. What are ways that you can reduce your ecological footprint?
POPULATION ECOLOGYChapter 53
You Must Know:
• How density, dispersion, and demographics can describe a population.
• The differences between exponential and logistic models of population growth.
• How density-dependent and density-independent factors can control population growth.
• Population = group of individuals of a single species living in same general area
• Rely on the same resources, Interact, and Interbreed
Introduction
Characterizing aPopulation
• Population Size -
changes to the # of
organisms in a
population• Involves adding &
removing individuals• Birth rate
• Death rate
• Immigration
• Emigration
Characterizing a Population
• Density - # of individuals per unit of area or volume• Count the # of individuals
• Mark-Recapture Method
• Also affected by birth rates, death
• rates, immigration, and emigration
density
Characterizing a Population
• Dispersion- spacing patterns within a population
Provides insight into theenvironmental associations& social interactions ofindividuals in population
Clumped Pattern (most common)
Uniform
• May result from
direct interactions
between individuals
in the population
• territoriality
Random
• Unpredictable patterns –
no strong attraction or
repulsion between the
individuals
Patterns of Dispersal:
1. Clumped – most common; near required resource
2. Uniform – usually antagonistic interactions
3. Random – not common in nature
Characterizing a Population
• Population Range - geographical limitations of a population
• Abiotic & biotic factors such as temperature, rainfall, food, predators, etc.
• Organisms have adaptations specific to their habitat
adaptations topolar biome
adaptations torainforest biome
Changes in Range
• Range expansions & contractions
• changing environment
At Risk Populations
• Endangered species are greatly affected by changes in range
• The more limited their range / habitat the more at risk the organisms are to extinction
Iriomote cat
New GuineatreekangarooNorthern white rhinoceros
SocorroisopodCatalina
Islandmahoganytree
IiwiHawaiianbird
Devil’s holepupfish
• Additions occur through birth, and subtractions occur through death.
• Life table : age-specific summary of the survival pattern of a population
• Represent data with a survivorship curve.
• Plot # of individuals in a cohort still alive at each age.
Demography: the study of vital statistics that affect population size
Life Table
Population Growth Rates
• Survivorship Curves - graphic representation of life table
• The relatively straight lines of the plots indicate relatively constant rates of death; however, males have a lower survival rate overall than females.
Survivorship Curves:
• Type I curve: low death rate early in life (humans)
• Type II curve: constant death rate over lifespan (squirrels)
• Type III curve: high death rate early in life (oysters)
Population Growth Rates
• Factors that affect population growth rates:• sex ratio
• how many females vs. males?• generation time
• at what age do females reproduce?• age structure
• How many cohorts (groups that are the same age) of females are able to reproduce?
Trade-offs: Survival vs. Reproduction• Reproduction has a cost…
• increase reproduction may decrease survival
• investment per offspring (how many offspring are produced and how much parental care is necessary)
• reproductive events per lifetime (how often they reproduce)
• when reproduction begins - age at first reproduction or at maturity Natural selection
favors a lifehistory thatmaximizes lifetimereproductivesuccess
Parental Survival
Kestrel Falcons:The cost of largerbroods to both male& female parents
Reproductive Strategies
Semelparity
•Big-bang reproduction
•Many offspring produced at once
•Individual often dies afterwards
•Less stable environments
•Selected by organisms rate of growth r-selected
•Fish, bugs and plants Agave Plant
Reproductive Strategies
Iteroparity
•Repeated reproduction
•Few, but large offspring
•More stable environments
•Selected by carrying capacity k-selected
•Mammals, birds, etc
Lizard
Critical factors: survival rate of offspring and repeated reproduction when resources are limited
• K-selection: pop. close to carrying capacity
• r-selection: maximize reproductive success
K-selection r-selectionLive around K Exponential growth
High prenatal care Little or no care
Low birth numbers High birth numbers
Good survival of young
Poor survival of young
Density-dependent Density independent
ie. Humans ie. cockroaches
N/t = B-D
N = population size
t = time
Change in Population Size
Change in population size
during time interval
Births during time interval
Deaths during time interval= -
• Zero population growth: B = D
• Exponential population growth: ideal conditions, population grows rapidly
• Unlimited resources are rare
• Logistic model: incorporates carrying capacity (K)
• K = maximum stable population which can be sustained by environment
• dN/dt = rmax((K-N)/K)
• S-shaped curve
Laboratory Populations
Factors that limit population growth:• Density-Dependent factors: population
matters
• i.e. Predation, disease, competition, territoriality, waste accumulation, physiological factors
• Density-Independent factors: population not a factor
• i.e. Natural disasters: fire, flood, weather
• Populations fluctuate due to biotic and abiotic factors
1975-1980: peak in wolf numbers1995: harsh winter weather (deep snow)
What do you notice about the population cycles of the showshoe hare and lynx?
Boom-and-bust cycles
• Predator-prey interactions
• Eg. lynx and snowshoe hare on 10-year cycle
Introduced Species• Non-native species
• transplanted populations grow exponentially in new area
• out-compete native species
• loss of natural controls
• lack of predators, parasites, competitors
• reduce diversity
• Ex.
• African honeybee
• gypsy moth
• water hyacinth
• zebra mussel
• purple loosestrife
kudzu
gypsy moth
Human Population Growth
• 2 configurations for a stable human population (zero population growth):
A. High birth / high death
B. Low birth / low death
• Demographic transition: occurs when population goes from A B
Population Growth Rates
• Age Structure – the relative number of individuals of each age
• Used to predict a populations growth trends and bring to light social conditions such as war, immigration, emigration, poor health care, etc.
What does the data imply about population growth inthese countries?
Global Carrying Capacity
• UN predicts: 7.8 to 10.8 billion people by the year 2050
• 2012 = 7 billion
• Estimated carrying capacity = 10-15 billion?
• Ecological footprint: total land + water area needed for all the resources a person consumes in a pop.
• 1.7 hectares (ha)/person is sustainable
• U.S.: 10 ha/person over K??
Limitations? Consequences? Solutions?
Human Population Growth
• 1650500 millionWhat factors havecontributed to thisexponential growthpattern?
1650500 million
Industrial Revolution
Significant advancesin medicine throughscience and technology
20056 billion
adding 82 million/yearPopulation of…China: 1.3 billionIndia: 1.1 billion
Map of ecological footprint of countries in the world
(proportional sizes shown)
Concept Check Questions
1. Define population.
2. What are the three types of dispersion?
3. What 4 things affect population size and density?
4. This relies on kin selection and reduces individual fitness but increases fitness of recipient.
5. This is the loss of response to stimulus