of the population. Population ecology - demecology. The dynamic characteristics
of the population.Lecture#3
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Ecology of individuals - autecology: organism and environment. Static
Содержание
- 1. Ecology of individuals - autecology: organism and environment. Static
- 2. Snapshot#31) Types of ecosystems in biosphere2)Biotic components
- 3. History The older term, autecology (from Greek:
- 4. Definition of autecologyPopulation ecology or autoecology is a sub-field of ecology that
- 5. Слайд 5
- 6. Terms used to describe natural groups of individuals in ecological studies
- 7. Populations have size and geographical boundaries.The density
- 8. MEASURING DENSITYDetermination of DensityCounting IndividualsEstimates By Counting
- 9. Measuring density of populations is a difficult
- 10. PATTERN OF DISPERSIONRANDOMUNIFORMCLUMPED
- 11. Patterns of dispersion.Within a population’s geographic range,
- 12. Слайд 12
- 13. Clumped Dispersion
- 14. Uniform Dispersion
- 15. Fig. 3.2cRandom Dispersion
- 16. Additions occur through birth, and subtractions occur
- 17. Population DynamicsCharacteristics of DynamicsSizeDensityDispersalImmigrationEmigrationBirthsDeathsSurvivorship
- 18. Parameters that effect size or density of
- 19. Age Structure: the proportion of individuals in each age class of a population
- 20. The best way to construct life table
- 21. A graphic way of representing the data
- 22. Survivorship Curve
- 23. Reproductive rates.Demographers that study populations usually ignore
- 24. Table 52.2Reproductive Table
- 25. Life histories are a result of natural
- 26. This is also known as semelparity.By contrast,
- 27. The life-histories represent an evolutionary resolution of
- 28. For example, red deer show a higher mortality rate in winters following reproductive episodes.
- 29. Variations also occur in seed crop size
- 30. We define a change in population size
- 31. Using mathematical notation we can express this
- 32. We can simplify the equation and use
- 33. Fig. 52.9
- 34. Typically, unlimited resources are rare.Population growth is
- 35. Example of Exponential GrowthKruger National Park, South Africa
- 36. LOGISTIC GROWTH RATE Assumes that the rate of
- 37. Figure 52.11 Population growth predicted by the logistic model
- 38. How well does the logistic model fit
- 39. Some of the assumptions built into the
- 40. The logistic population growth model and life
- 41. K-Selected SpeciesPoor colonizersSlow maturityLong-livedLow fecundityHigh investment in
- 42. Why do all populations eventually stop growing?What
- 43. Density-Dependent Factorslimiting resources (e.g., food & shelter)production of toxic wastesinfectious diseasespredationstressemigration
- 44. Density-Independent Factorssevere storms and floodingsudden unpredictable severe cold spellsearthquakes and volcanoescatastrophic meteorite impacts
- 45. Density-dependent factors increase their affect on a
- 46. A variety of factors can cause negative
- 47. Intraspecific competition for food can also cause density-dependent behavior of populations.Territoriality.Predation.
- 48. Carrying capacity can vary.Year-to-year data can be
- 49. Some populations fluctuate erratically, based on many factors.Fig. 52.18
- 50. Other populations have regular boom-and-bust cycles.There are
- 51. Слайд 51
- 52. The human population increased relatively slowly until
- 53. POPULATION CYCLESHUMAN POPULATION 1650 - 500,000,000 1850 - ONE
- 54. Fig. 52.20
- 55. Human Growth Rate1.15 - 2005
- 56. The Demographic Transition.A regional human population can
- 57. The movement from the first toward the second state is called the demographic transition.Fig. 52.21
- 58. Age structure.Age structure is the relative number
- 59. Fig. 52.22
- 60. Predictions of the human population vary from
- 61. Wide range of estimates for carrying capacity.What
- 62. For each nation, we can calculate the
- 63. The ecological footprints in relation to available ecological capacity.
- 64. We may never know Earth’s carrying capacity
- 65. Скачать презентанцию
Snapshot#31) Types of ecosystems in biosphere2)Biotic components of ecosystem. Biotic components include 3 categories. Please write them3)Abiotic components of ecosystem4)Important cycles in Ecosystem5)What are adaptations?
Слайды и текст этой презентации
Слайд 1Ecology of individuals - autecology: organism and environment. Static characteristics
Слайд 2Snapshot#3
1) Types of ecosystems in biosphere
2)Biotic components of ecosystem. Biotic
components include 3 categories. Please write them
3)Abiotic components of ecosystem
4)Important
cycles in Ecosystem5)What are adaptations?
Слайд 3History
The older term, autecology (from Greek: αὐτο, auto, "self"; οίκος, oikos,
"household"; and λόγος, logos, "knowledge"), refers to roughly the same
field of study as population ecology.It derives from the division of ecology into autecology—the study of individual species in relation to the environment
Слайд 4Definition of autecology
Population ecology or autoecology is a sub-field of ecology that deals with the
dynamics of species populations and how these populations interact with the environment. It is
the study of how the population sizes of species living together in groups change over time and space.The branch of ecology that deals with the biological relationship between an individual organism or an individual species and its environment.
Слайд 7Populations have size and geographical boundaries.
The density of a population
is measured as the number of individuals per unit area.
The
dispersion of a population is the pattern of spacing among individuals within the geographic boundaries.The characteristics of populations are shaped by the interactions between individuals and their environment
Слайд 8MEASURING DENSITY
Determination of Density
Counting Individuals
Estimates By Counting Individuals
Estimates By Indirect
Indicators
Mark-recapture Method
N = (Number Marked) X (Catch Second
Time)Number Of Marked Recaptures
Density – Number of individuals per unit
of area.
Слайд 9Measuring density of populations is a difficult task.
We can count
individuals; we can estimate population numbers.
Fig. 52.1
Слайд 11Patterns of dispersion.
Within a population’s geographic range, local densities may
vary considerably.
Different dispersion patterns result within the range.
Overall, dispersion depends
on resource distribution.
Слайд 16Additions occur through birth, and subtractions occur through death.
Demography studies
the vital statistics that affect population size.
Life tables and survivorship
curves.A life table is an age-specific summary of the survival pattern of a population.
Demography is the study of factors that affect the growth and decline of
populations
Слайд 17Population Dynamics
Characteristics of Dynamics
Size
Density
Dispersal
Immigration
Emigration
Births
Deaths
Survivorship
Слайд 18Parameters that effect size or density of a population:
Figure 1.
The size of a population is determined by a balance
between births, immigration, deaths and emigrationBirth
Death
Emigration
Immigration
Population (N)
Слайд 20The best way to construct life table is to follow
a cohort, a group of individuals of the same age
throughout their lifetime.Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Table 52.1
Слайд 21A graphic way of representing the data is a survivorship
curve.
This is a plot of the number of individuals in
a cohort still alive at each age.A Type I curve shows a low death rate early in life (humans).
The Type II curve shows constant mortality (squirrels).
Type III curve shows a high death rate early in life (oysters).
Слайд 23Reproductive rates.
Demographers that study populations usually ignore males, and focus
on females because only females give birth to offspring.
A reproductive
table is an age-specific summary of the reproductive rates in a population.For sexual species, the table tallies the number of female offspring produced by each age group.
Слайд 25Life histories are a result of natural selection, and often parallel environmental
factors.
Some organisms, such as the
agave plant,exhibit what is
known as big-bang
reproduction,
where large
numbers of offspring are
produced in each reproduction,
after which the individual
often dies.Life histories are very diverse, but they exhibit patterns in their variability
Agaves
Слайд 26This is also known as semelparity.
By contrast, some organisms produce
only a few eggs during repeated reproductive episodes.
This is also
known as iteroparity.What factors contribute to the evolution of semelparity and iteroparity?
Слайд 27The life-histories represent an evolutionary resolution of several conflicting demands.
Sometimes
we see trade-offs between survival and reproduction when resources are
limited.Limited resources mandate trade-offs between investments in reproduction and survival
Слайд 28For example, red deer show a higher mortality rate in
winters following reproductive episodes.
Слайд 29Variations also occur in seed crop size in plants.
The number
of offspring produced at each reproductive episode exhibits a trade-off
between number and quality of offspring.dandelion
Coconut palm
Слайд 30We define a change in population size based on the
following verbal equation.
Change in population = Births during
– Deaths duringsize during time interval time interval time interval
The exponential model of population describes an idealized population in an unlimited environment
Слайд 31Using mathematical notation we can express this relationship as follows:
If
N represents population size, and t represents time, then N
is the change is population size and t represents the change in time, then:N/t = B-D
Where B is the number of births and D is the number of deaths
Слайд 32We can simplify the equation and use r to represent
the difference in per capita birth and death rates.
N/t =
rN OR dN/dt = rNIf B = D then there is zero population growth (ZPG).
Under ideal conditions, a population grows rapidly.
Exponential population growth is said to be happening
Under these conditions, we may assume the maximum growth rate for the population (rmax) to give us the following exponential growth
dN/dt = rmaxN
Слайд 34Typically, unlimited resources are rare.
Population growth is therefore regulated by
carrying capacity (K), which is the maximum stable population size
a particular environment can support.The logistic model of population growth incorporates the concept of carrying capacity
Слайд 36LOGISTIC GROWTH RATE
Assumes that the rate of population
growth slows as
the population size
approaches carrying capacity, leveling
to a constant
level. S-shaped curveCARRYING CAPACITY
The maximum sustainable population
a particular environment can support
over a long period of time.
POPULATION GROWTH RATE
Слайд 38How well does the logistic model fit the growth of
real populations?
The growth of laboratory populations of some animals fits
the S-shaped curves fairly well.Stable population
Seasonal increase
Слайд 39Some of the assumptions built into the logistic model do
not apply to all populations.
It is a model which provides
a basis from which we can compare real populations.Severe Environmental Impact
Слайд 40The logistic population growth model and life histories.
This model predicts
different growth rates for different populations, relative to carrying capacity.
Resource
availability depends on the situation.The life history traits that natural selection favors may vary with population density and environmental conditions.
In K-selection, organisms live and reproduce around K, and are sensitive to population density.
In r-selection, organisms exhibit high rates of reproduction and occur in variable environments in which population densities fluctuate well below K.
Слайд 41K-Selected Species
Poor colonizers
Slow maturity
Long-lived
Low fecundity
High investment in care for the
young
Specialist
Good competitors
Good colonizers
Reach maturity rapidly
Short-lived
High fecundity
Low investment in care for
the youngGeneralists
Poor competitors
r-Selected Species
Слайд 42Why do all populations eventually stop growing?
What environmental factors stop
a population from growing?
The first step to answering these questions
is to examine the effects of increased population density.
Слайд 43Density-Dependent Factors
limiting resources (e.g., food & shelter)
production of toxic wastes
infectious
diseases
predation
stress
emigration
Слайд 44Density-Independent Factors
severe storms and flooding
sudden unpredictable severe cold spells
earthquakes and
volcanoes
catastrophic meteorite impacts
Слайд 45Density-dependent factors
increase their affect on a population as population
density increases.
This is a type of negative
feedback.
Density-independent factors
are unrelated to
population
density, and there is no
feedback to slow population
growth.
Слайд 46A variety of factors can cause negative feedback.
Resource limitation in
crowded populations can stop population growth by reducing reproduction.
Negative feedback
prevents unlimited population growth
Слайд 47Intraspecific competition for food can also cause density-dependent behavior of
populations.
Territoriality.
Predation.
Слайд 48Carrying capacity can vary.
Year-to-year data can be helpful in analyzing
population growth.
Population dynamics reflect a complex interaction of biotic
and abiotic influences
Слайд 50Other populations have regular boom-and-bust cycles.
There are populations that fluctuate
greatly.
A good example involves the lynx and snowshoe hare that
cycle on a ten year basis.
Слайд 52The human population increased relatively slowly until about 1650 when the
Plague took an untold number of lives.
Ever since, human population
numbers have doubled twiceHow might this population increase stop?
The human population has been growing almost exponentially for three centuries but cannot do so indefinitely
Слайд 53POPULATION CYCLES
HUMAN POPULATION
1650 - 500,000,000
1850 - ONE BILLION
1930 - TWO
BILLION
1975 - FOUR BILLION
2010 – SIX BILLION
2017 - EIGHT BILLION
Слайд 56The Demographic Transition.
A regional human population can exist in one
of 2 configurations.
Zero population growth = high birth rates –
high death rates.Zero population growth = low birth rates – low death rates.
Слайд 57The movement from the first toward the second state is
called the demographic transition.
Fig. 52.21
Слайд 58Age structure.
Age structure is the relative number of individuals of
each age.
Age structure diagrams can reveal a population’s growth trends,
and can point to future social conditions.
Слайд 60Predictions of the human population vary from 7.3 to 10.7
billion people by the year 2050.
Will the earth be overpopulated
by this time?Estimating Earth’s carrying capacity for humans is a complex problem
Слайд 61Wide range of estimates for carrying capacity.
What is the carrying
capacity of Earth for humans?
This question is difficult to answer.
Estimates
are usually based on food, but human agriculture limits assumptions on available amounts.Ecological footprint.
Humans have multiple constraints besides food.
The concept an of ecological footprint uses the idea of multiple constraints.
Слайд 62For each nation, we can calculate the aggregate land and
water area in various ecosystem categories.
Six types of ecologically productive
areas are distinguished in calculating the ecological footprint:Land suitable for crops.
Pasture.
Forest.
Ocean.
Built-up land.
Fossil energy land.
Слайд 64We may never know Earth’s carrying capacity for humans, but
we have the unique responsibility to decide our fate and
the fate of the rest of the biosphere.
