5) The distribution of terrestrial biomes is based mainly on regional variations in climate.

1
1) Interactions between organisms and environment
determine distribution and abundance dispersal,
habitat selection, biotic factors, abiotic
factors (climate very important temperature and
water).
2) Temporal and spatial scales of studies are
important.
3) Global climate mostly determined by solar
energy and earths movement in space. Permanent
tilt on Earths axis causes seasonal variation in
light, temperature and wind patterns. Hence,
seasonal variation in distribution and abundance
of organisms.
4) Aquatic biomes occupy the largest part of the
biosphere oceans have a major effect on global
and local climate freshwater biomes are closely
linked to terrestrial biomes.
5) The distribution of terrestrial biomes is
based mainly on regional variations in climate.
2
Largest component. Vertical stratification
light, temperature, salinity, density. Oceans (3
salt) rainfall, climate, wind. Give O2 and take
CO2. Freshwater (lt 1 salt) linked to soil and
biota of terrestrial biomes.
Aquatic Biomes
Fig. 50.17
pages 1106-1109
3
Ocean zonation
Fig. 50.22
Distance to shore water depth, light
penetration, substrate.
pages 1109-1112
4
Terrestrial Biomes
Determined by climate latitudinal and regional
patterns. Vertical stratification based on
vegetation. Characteristic life forms. Gradation
in boundaries ecotone. Dynamic, not stable.
Fig. 50.24
pages 1112-1113
5
SOME questions from February 8th
1- Are we going to be tested on material that you
have not covered in lecture?
2- When will the review sheet be posted? Will we
have a study/review session?
3- Will there be questions about the third
article on the test?
4- Do any chemicals evaporate with water or does
water always separate from anything it is mixed
with?
5- What is the Ekman transport vector? Why is it
important?
6- What are the lowest points in the ocean? What
could possibly live there?
6
Chapter 52- Population Ecology
Population ecology limiting factors
Organismal ecology coping
Community ecology interspecific interactions and
diversity
Ecosystem ecology energy flow and chemical cycling
Landscape ecology effects on interactions at
lower levels
Biosphere ecology global effects
7
Population Group of individuals of the same
species occupying the same general area.
67,171- 2000 Census
71,080- 2004 Estimate
Density. Dispersion.
pages 1151-1152
8
Uniform
Fig. 52.2
page 1153
Clumped
Dispersion Patterns
Random
9
Changes in Population Size
pages 1153 (1154)
Additions () Natality (births). Immigration.
Subtractions (-) Mortality (deaths). Emigration.

Demography Studies vital statistics that affect
population size.
Life Histories
Island of Rhum, Scotland
Reproductive success. Number of surviving
offspring produced by an individual and that
reach reproductive age. Natural selection.
Differences in reproductive success due to
heritable differences in individuals. Life
histories. Patterns of resource allocation to
maintenance (survival), growth, and reproduction.
Fig. 52.5
pages 1156-1158
Individuals expected to behave so as to promote
their own RS.
10
Life Histories
Iteroparity.
Semelparity
(once and beget)
(repeat and beget)
Three basic life history decisions (remember
not conscious choice except us) -When to
begin reproducing? -How often to breed?
-How many offspring to produce during each
reproductive episode?
TID
page 1156
11
Population Growth
population is growing ( gt1 ) population is
declining ( lt1 ) zero population growth ( 1 )
Finite rate of increase
? number of individuals at time t 1 divided
by number of individuals at time t
population is growing ( r ) population is
declining ( r- ) zero population growth ( r 0 )
Instantaneous rate of change
r ln ?
r
change
Nt
Nt1
?
115 100
100 115
100 100
0.87
-0.14
-13



1.15
0.14
15
1
0
0
pages 1158-1159
12
Population Growth
Exponential model
Ideal conditions population growth constrained
only by life history.
rmax maximum growth rate for the species
Intrinsic rate of growth rate
exponential population growth or geometric
population growth
pages 1159-1160
13
Population Growth
Logistic model There is a limit to number of
individuals that can occupy a habitat.
Carrying capacity (K). Maximum population size
an environment can support at a time with no
habitat degradation. Not a fixed value.
Population growth rapid when population size well
below K, slow when close to K and zero when at K.
K 100 N 1 (K-N)/K 0.99 K 100 N
90 (K-N)/K 0.1 K 100 N 100
(K-N)/K 0
pages 1160-1161
14
Population Growth
Number of individuals
r 0.02
r 0.02
Time
Exponential curve. Population grows indefinitely.
S-shaped curve. Population growth levels off as
population size approaches carrying capacity.
pages 1161-1162
15
Halichoerus grypus
Sable Island, CAN
ICES J. Mar. Sci. 2003
Phoca vitulina
pages 1162-1163
J. Wildl. Manage. 2003
16
Population-Limiting Factors
Many factors cause changes in birth and death
rates in relation to population density
increased predation, competition for food or
space, stress, parasitism, etc slowing
population growth rate.
Eubalaena glacialis
Why do they represent an example of negative
feedback?
Food-limited
CRESLI
Mandarte Isl., BC
Fig. 52.14
pages 1164-1165
17
Dynamics of Populations
They result from the interaction between biotic
and abiotic factors. Long-term studies indicate
that such factors make natural populations
unstable.
Assigned paper to read for Quiz IV.
Isla Royale, Michigan
Fig. 52.17
pages 1165-1167
18
Fig. 52.19
-Geographic variations due to large-scale climate
effects (apparent lack of lynx migration between
regions).
PNAS 2004
-Fluctuations of food species. -Predation by
various species.
-Hare fluctuations.
Some populations have regular boom-and-bust
cycles.
pages 1167-1168