THE ECOLOGICAL STUFF….

AP Bio Summer assignment Ch 52 and 53

Overview: The Scope of Ecology

Ecology is the scientific study of the interactions between organisms and the environment

These interactions determine distribution of organisms and their abundance

Ecology reveals the richness of the biosphere

Fig. 52-2Organismalecology

Populationecology

Communityecology

Ecosystemecology

Landscapeecology

Globalecology

A population is a group of individuals of the same species living in an area

Population ecology focuses on factors affecting how many individuals of a species live in an area

A community is a group of populations of different species in an area

Community ecology deals with the whole array of interacting species in a community

An ecosystem is the community of organisms in an area and the physical factors with which they interact

Ecosystem ecology emphasizes energy flow and chemical cycling among the various biotic and abiotic components

Fig. 52-2f

Ecology and Environmental Issues

Ecology provides the scientific understanding that underlies environmental issues

Ecologists make a distinction between science and advocacy

Rachel Carson is credited with starting the modern environmental movement with the publication of Silent Spring in 1962

Fig. 52-4

Concept 52.2: Interactions between organisms and the environment limit the distribution of species

Ecologists have long recognized global and regional patterns of distribution of organisms within the biosphere

Biogeography is a good starting point for understanding what limits geographic distribution of species

Ecologists recognize two kinds of factors that determine distribution: biotic, or living factors, and abiotic, or nonliving factors

Fig. 52-5

Kangaroos/km2

0–0.10.1–11–55–1010–20> 20Limits ofdistribution

Dispersal and Distribution

Dispersal is movement of individuals away from centers of high population density or from their area of origin

Dispersal contributes to global distribution of organisms

Natural range expansions show the influence of dispersal on distribution

Fig. 52-7

Current

1966

1970

1965 1960

19611958

1951

1943

1937

1956

1970

Species Transplants

Species transplants include organisms that are intentionally or accidentally relocated from their original distribution

Species transplants can disrupt the communities or ecosystems to which they have been introduced

Behavior and Habitat Selection

Some organisms do not occupy all of their potential range

Species distribution may be limited by habitat selection behavior

Biotic Factors

Biotic factors that affect the distribution of organisms may include:Interactions with other speciesPredationCompetition

Fig. 52-8

RESULTS

Sea urchin

100

80

60

40

20

0

Limpet

Seaw

eed c

ove

r (%

)Both limpets and urchinsremoved

Only urchinsremoved

Only limpets removedControl (both urchinsand limpets present)

August1982

August1983

February1983

February1984

Abiotic Factors

Abiotic factors affecting distribution of organisms include:TemperatureWaterSunlightWindRocks and soil

Most abiotic factors vary in space and time

Climate

Four major abiotic components of climate are temperature, water, sunlight, and wind

The long-term prevailing weather conditions in an area constitute its climate

Macroclimate consists of patterns on the global, regional, and local level

Microclimate consists of very fine patterns, such as those encountered by the community of organisms underneath a fallen log

Fig. 52-10aLatitudinal Variation in Sunlight Intensity

Low angle of incoming sunlight

Sun directly overhead at equinoxes

Low angle of incoming sunlight

Atmosphere90ºS (South Pole)60ºS

30ºS

23.5ºS (Tropic ofCapricorn)

0º (equator)

30ºN23.5ºN (Tropic ofCancer)

60ºN90ºN (North Pole)

Seasonal Variation in Sunlight Intensity

60ºN30ºN

30ºS

0º (equator)

March equinox

June solstice

Constant tiltof 23.5º

September equinox

December solstice

Fig. 52-10e

Descendingdry airabsorbsmoisture

Descendingdry airabsorbsmoisture

Ascendingmoist airreleasesmoisture

Aridzone

Aridzone

Tropics

30º 23.5º 0º 23.5º30º

60ºN

30ºN

0º(equator)

30ºS

60ºS

Fig. 52-10f

0º(equator)

30ºS

60ºS66.5ºS(Antarctic Circle)

30ºN

66.5ºN(Arctic Circle)

60ºNWesterlies

Northeast trades

Doldrums

Southeast trades

Westerlies

Bodies of WaterThe Gulf Stream carries warm water

from the equator to the North AtlanticOceans and their currents and large

lakes moderate the climate of nearby terrestrial environments

Fig. 52-11

Labradorcurrent

Gulfstream

Equator

Cold water

Warmwater

Fig. 52-12

Warm airover land rises.

1

23

4

Air cools athigh elevation.

Cool air over watermoves inland, replacingrising warm air over land.

Coolerair sinksover water.

MountainsMountains have a significant effect on

The amount of sunlight reaching an areaLocal temperatureRainfall

Rising air releases moisture on the windward side of a peak and creates a “rain shadow” as it absorbs moisture on the leeward side

Fig. 52-13

Winddirection

Mountainrange

Leeward sideof mountain

Ocean

Aquatic biomes account for the largest part of the biosphere in terms of area

They can contain fresh water or salt water (marine)

Oceans cover about 75% of Earth’s surface and have an enormous impact on the biosphere

Fig. 52-15

LakesCoral reefsRiversOceanicpelagic andbenthic zonesEstuariesIntertidal zones

Tropic ofCancerEquator

Tropic ofCapricorn

30ºN

30ºS

Fig. 52-16b

(b) Marine zonation

2,000–6,000 mAbyssal zone

Benthiczone

Aphoticzone

Pelagiczone

Continentalshelf

200 mPhotic zone

0

Oceanic zoneNeritic zone

Intertidal zone

The upper photic zone has sufficient light for photosynthesis while the lower aphotic zone receives little light

The organic and inorganic sediment at the bottom of all aquatic zones is called the benthic zone

The communities of organisms in the benthic zone are collectively called the benthos

Detritus, dead organic matter, falls from the productive surface water and is an important source of food

The most extensive part of the ocean is the abyssal zone with a depth of 2,000 to 6,000 m

Fig. 52-16a

Littoralzone Limnetic

zone

Photiczone

PelagiczoneBenthic

zoneAphoticzone

(a) Zonation in a lake

Fig. 52-17-5

Winter

4º4º

4º

4ºC

4º4º

Spring Summer Autumn

Thermocline

4º4º

4º

4ºC

4º4º

4º4º

4º

4ºC

2º0º

4ºC5º6º

8º18º

20º22º

Terrestrial BiomesTerrestrial biomes can be characterized

by distribution, precipitation, temperature, plants, and animals

Tropical ForestIn tropical rain forests, rainfall is

relatively constant, while in tropical dry forests precipitation is highly seasonal

Tropical forests are vertically layered and competition for light is intense

Tropical forests are home to millions of animal species, including an estimated 5–30 million still undescribed species of insects, spiders, and other arthropods

Fig. 52-21a

A tropical rain forest in Borneo

DesertPrecipitation is low and highly variable,

generally less than 30 cm per year; deserts may be hot or cold

Desert plants are adapted for heat and desiccation tolerance, water storage, and reduced leaf surface area

Common desert animals include many kinds of snakes and lizards, scorpions, ants, beetles, migratory and resident birds, and seed-eating rodents; many are nocturnal

Fig. 52-21b

A desert in the southwesternUnited States

SavannaSavanna precipitation and temperature

are seasonalGrasses and forbs make up most of the

ground coverCommon inhabitants include insects and

mammals such as wildebeests, zebras, lions, and hyenas

Fig. 52-21c

A savanna in Kenya

ChaparralChaparral climate is highly seasonal,

with cool and rainy winters and hot dry summers

The chaparral is dominated by shrubs, small trees, grasses, and herbs; many plants are adapted to fire and drought

Animals include amphibians, birds and other reptiles, insects, small mammals and browsing mammals

Fig. 52-21d

An area of chaparralin California

Temperate GrasslandTemperate grasslands are found on

many continentsWinters are cold and dry, while summers

are wet and hotThe dominant plants, grasses and forbs,

are adapted to droughts and fireNative mammals include large grazers

and small burrowers

Fig. 52-21e

Sheyenne National Grasslandin North Dakota

Northern Coniferous ForestThe northern coniferous forest, or

taiga, extends across northern North America and Eurasia and is the largest terrestrial biome on Earth

Winters are cold and long while summers may be hot

The conical shape of conifers prevents too much snow from accumulating and breaking their branches

Animals include migratory and resident birds, and large mammals

Fig. 52-21f

Rocky Mountain National Parkin Colorado

Temperate Broadleaf ForestWinters are cool, while summers are hot

and humid; significant precipitation falls year round as rain and snow

A mature temperate broadleaf forest has vertical layers dominated by deciduous trees in the Northern Hemisphere and evergreen eucalyptus in Australia

Mammals, birds, and insects make use of all vertical layers in the forest

In the Northern Hemisphere, many mammals hibernate in the winter

Fig. 52-21g

Great Smoky MountainsNational Park in North Carolina

TundraTundra covers expansive areas of the

Arctic; alpine tundra exists on high mountaintops at all latitudes

Winters are long and cold while summers are relatively cool; precipitation varies

Permafrost, a permanently frozen layer of soil, prevents water infiltration

Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) and supports birds, grazers, and their predators

Fig. 52-21h

Denali National Park, Alaska,in autumn

Population ecology is the study of populations in relation to environment, including environmental influences on density and distribution, age structure, and population size

A population is a group of individuals of a single species living in the same general area

Density is the result of an interplay between processes that add individuals to a population and those that remove individuals

Immigration is the influx of new individuals from other areas

Emigration is the movement of individuals out of a population

Fig. 53-3

Births

Births and immigrationadd individuals toa population.

Immigration

Deaths and emigrationremove individualsfrom a population.

Deaths

Emigration

Patterns of Dispersion

Environmental and social factors influence spacing of individuals in a population

In a clumped dispersion, individuals aggregate in patches

A clumped dispersion may be influenced by resource availability and behavior

Fig. 53-4

(a) Clumped

(b) Uniform

(c) Random

Demographics

Demography is the study of the vital statistics of a population and how they change over time

Death rates and birth rates are of particular interest to demographers

Life Tables

A life table is an age-specific summary of the survival pattern of a population

It is best made by following the fate of a cohort, a group of individuals of the same age

The life table of Belding’s ground squirrels reveals many things about this population

Table 53-1

Survivorship Curves

A survivorship curve is a graphic way of representing the data in a life table

The survivorship curve for Belding’s ground squirrels shows a relatively constant death rate

Fig. 53-5

Age (years)20 4 86

10

101

1,000

100

Nu

mb

er

of

surv

ivors

(lo

g s

cale

)

Males

Females

Survivorship curves can be classified into three general types:Type I: low death rates during early and middle

life, then an increase among older age groupsType II: the death rate is constant over the

organism’s life spanType III: high death rates for the young, then a

slower death rate for survivors

Fig. 53-6

1,000

100

10

10 50 100

II

III

Percentage of maximum life span

Nu

mb

er

of

surv

ivors

(lo

g s

cale

)

I

Reproductive Rates

For species with sexual reproduction, demographers often concentrate on females in a population

A reproductive table, or fertility schedule, is an age-specific summary of the reproductive rates in a population

It describes reproductive patterns of a population

Table 53-2

Fig. 53-9

(a) Dandelion

(b) Coconut palm

Exponential Growth

Exponential population growth is population increase under idealized conditions

Under these conditions, the rate of reproduction is at its maximum, called the intrinsic rate of increase

Fig. 53-11

8,000

6,000

4,000

2,000

01920 1940 1960 1980

Year

Ele

ph

an

t p

op

ula

tion

1900

Concept 53.4: The logistic model describes how a population grows more slowly as it nears its carrying capacity

Exponential growth cannot be sustained for long in any population

A more realistic population model limits growth by incorporating carrying capacity

Carrying capacity (K) is the maximum population size the environment can support

Fig. 53-12

2,000

1,500

1,000

500

00 5 10 15

Number of generations

Pop

ula

tion

siz

e (N

)

Exponentialgrowth

1.0N=dNdt

1.0N=dNdt

K = 1,500

Logistic growth1,500 – N

1,500

Some populations overshoot K before settling down to a relatively stable density

Fig. 53-13b

Nu

mb

er

of Daphnia

/50

mL

0

30

60

90

180

150

120

0 20 40 60 80 100 120 140 160Time (days)

(b) A Daphnia population in the lab

The Logistic Model and Life Histories

Life history traits favored by natural selection may vary with population density and environmental conditions

K-selection, or density-dependent selection, selects for life history traits that are sensitive to population density

r-selection, or density-independent selection, selects for life history traits that maximize reproduction

Population Change and Population Density

In density-independent populations, birth rate and death rate do not change with population density

In density-dependent populations, birth rates fall and death rates rise with population density

Fig. 53-15

(a) Both birth rate and death rate vary.

Population density

Density-dependentbirth rate

Equilibriumdensity

Density-dependentdeath rate

Bir

th o

r d

eath

rate

per

cap

ita

(b) Birth rate varies; death rate is constant.

Population density

Density-dependentbirth rate

Equilibriumdensity

Density-independentdeath rate

(c) Death rate varies; birth rate is constant.

Population density

Density-dependentdeath rate

Equilibriumdensity

Density-independentbirth rate

Bir

th o

r d

eath

rate

per

cap

ita

Disease

Population density can influence the health and survival of organisms

In dense populations, pathogens can spread more rapidly

Predation

As a prey population builds up, predators may feed preferentially on that species

Toxic Wastes

Accumulation of toxic wastes can contribute to density-dependent regulation of population size

Intrinsic Factors

For some populations, intrinsic (physiological) factors appear to regulate population size

Population Dynamics

The study of population dynamics focuses on the complex interactions between biotic and abiotic factors that cause variation in population size

Stability and Fluctuation

Long-term population studies have challenged the hypothesis that populations of large mammals are relatively stable over time

Weather can affect population size over time

Fig. 53-18

2,100

1,900

1,700

1,500

1,300

1,100

900

700

500

01955 1965 1975 1985 1995 2005

Year

Nu

mb

er

of

sheep

Fig. 53-19

Wolves Moose

2,500

2,000

1,500

1,000

500

Nu

mb

er

of

moose

0

Nu

mb

er

of

wolv

es

50

40

30

20

10

01955 1965 1975 1985 1995 2005

Year

Fig. 53-20

Snowshoe hare

Lynx

Nu

mber

of

lyn

x(t

hou

san

ds)

Nu

mber

of

hare

s(t

hou

san

ds)

160

120

80

40

01850 1875 1900 1925

Year

9

6

3

0

Concept 53.6: The human population is no longer growing exponentially but is still increasing rapidly

No population can grow indefinitely, and humans are no exception

Fig. 53-22

8000B.C.E.

4000B.C.E.

3000B.C.E.

2000B.C.E.

1000B.C.E.

0 1000C.E.

2000C.E.

0

1

2

3

4

5

6

The Plague

Hu

man

pop

ula

tion

(b

illi

on

s)

7

Regional Patterns of Population Change

To maintain population stability, a regional human population can exist in one of two configurations:Zero population growth =

High birth rate – High death rateZero population growth =

Low birth rate – Low death rateThe demographic transition is the

move from the first state toward the second state

The demographic transition is associated with an increase in the quality of health care and improved access to education, especially for women

Most of the current global population growth is concentrated in developing countries

Age Structure

One important demographic factor in present and future growth trends is a country’s age structure

Age structure is the relative number of individuals at each age

Age structure diagrams can predict a population’s growth trends

They can illuminate social conditions and help us plan for the future

Fig. 53-25

Rapid growthAfghanistan

Male Female Age AgeMale Female

Slow growthUnited States

Male Female

No growthItaly

85+80–8475–7970–74

60–6465–69

55–5950–5445–4940–4435–3930–3425–2920–2415–19

0–45–9

10–14

85+80–8475–7970–74

60–6465–69

55–5950–5445–4940–4435–3930–3425–2920–2415–19

0–45–9

10–14

10  10 8 866 4 422 0Percent of population Percent of population Percent of population

66 4 422 08 8 66 4 422 08 8

Limits on Human Population Size

The ecological footprint concept summarizes the aggregate land and water area needed to sustain the people of a nation

It is one measure of how close we are to the carrying capacity of Earth

Countries vary greatly in footprint size and available ecological capacity

Fig. 53-27

Log (g carbon/year)13.49.85.8

Not analyzed