Transcript 第III部分：种群生态学

第II部分：种群生态学 ( Population Ecology)
Population种群：A group of individuals of a single species
inhabiting a specific area.居住在特定区域的某种生物所有个体)
第5章Population Distribution and abundance 种群分布与数量
Environment limits the geographic distribution of species
On small scales, individuals within populations are
distributed in patterns that may be random, regular, or
clumped
On large scales, individuals within populations are clumped
Population density declines with increasing organism size
9.1 Distribution Limits
Environment limits the
geographic distribution
of species
（1）Kangaroo Distributions
and Climate
大袋鼠
灰袋鼠
红袋鼠
澳洲三种袋鼠的分布与气候的关系
(2) A Tiger Beetle of Cold Climates
During the last glacial
period, C. longilabris lived
far south of its present range
limits. Then with climate
warming and the retreat of
the glaciers, the beetles
followed their preferred
climate northward and up in
elevation into the mountains
of western NM.
C. longilabris confined to cool
environments
Physiological
ecology:
（续）
Water loss rates (水分散失率),
metabolic rates (代谢速率)
分
开
一
万
年
Body temperature preference
(体温偏好) , et al.
The studies show that
environmental limits may be
stable for long periods of
time and across an extensive
geographic range
Uniform temperature preference across
an extensive geographic range
（3）Distributions of plants along a moisture-temperature
gradient（梯度）
夏季叶密被毛,
反射约40％
无毛被, 反射约15％
叶面光滑
略被毛,
反射约26％
The humidity declines, but temperature increases
The distribution of four Encelia species in southwestern North America
（续）
E. farinose and E. frutescens are overlapped
in distribution.
Though they have
different densities
of pubescent
leaves, they have
similar leaf
temperatures.
How can that be?
Light absorption by leaves of Encelia
（续）
Losing heat by transpiration(蒸腾降温) needs more water
Smooth leaves
Temperature regulation and distributions of E. farinosa and E. frutescens
(4) Distributions of Barnacles (藤壶) along an intertidal(潮间）
exposure gradient
Why does
Chthamalus stay at
higher levels if it
survives well at the
lower?
?
Distributions of two barnacle (藤壶）species within the inter-tidal zone
（续）
Vulnerability
to Desiccation(干燥）? Yes. But it is enough?
Chthamalus
survives very
well in the lower
zone. But why
not?
larvae
adults
上潮间带藤壶的死亡率
9.2 Patterns on Small Scales
On small scales, individuals within populations are
distributed in patterns that may be random, regular, or
clumped
Small scale：areas over which there is little environmental
change significant to the organism under study.
Large scale: areas over which there is substantial environmental
change.
Scale !
(1) Three distribution patterns on small scales
随机
均匀
聚集
（a）Distribution of tropical bee colonies (蜜蜂群）
Bees: Stingless bees (Trigonalydae) in tropical dry forest
in Cost Rica
Habits: Feeding pollen and nectar; nesting on trees; some
species are highly aggressive and foraging in groups, while
others are not.
question：Is there a relationship between aggressiveness and
colony distribution pattern ?
Research methods: (i) Mapping distributions of trees
suitable for nesting, and then (ii) mapping nests.
Results:
(b) Distribution of desert shrubs 荒漠灌木的空间分布
Regular, Random, Clumped, or Both?
Are local population of the creosote (木馏油)distributed regularly?
（续） & MacMahon (1981):
Phillips
续
Methods: Competition belowground? Excavating(挖)
roots, and then mapping them.
Conclusion: The competition influences the distribution.
Creosote bush root distributions: hypothetical versus actual root overlap (1994)
9.3 Distribution on large scales
(1) Geographic range
sizes
Most of species are
distributed in
small areas, while
only a few in large
areas.
(2) Range size and
abundance
A positive
relationship
9.4 Organism size and population
density
(1) Animal size
and density
J. Damuth
（1981）: 307
herbivorous
mammals from as
small as 10g in a
small mice to as
large as 106 g
rhino,
Negative correlation
Body size and population density of herbivorous
(植食性）mammals（哺乳动物）
（i）overall pattern: negative correlation between S and D
（ii）Aquatic invertebrates tend to have higher densities than
terrestrial invertebrates.
(iii) Mammals tend to have higher densities than birds
Animal size and population density
（2） Plant size and Density
White（1985）found a
similar relationship
between plant size and
density in plants as that
in animals.
浮萍
红树
The value of such
relationships?
Plant size and population density
9.5 Factors that Limit Distributions
限制分布的因素
Temperature, Moisture,
and Other Physical Factors
Dispersal
Distribution
Habitat Selection
Interrelations
with other species
9.6 Methods for Analyzing Distributions
（1） Transplant (移植) Experiments
Liebig’s Law of the Minimum (李比希最小因子定律）：the
rate of any biological process is limited by the factor in least
amount relative to requirements. 低于某生物需要的最小量的
任何特定因子，是决定该种生物生存和分布的关键因素。
移植存活
实际分布区
潜在分布区
（2）Physiological Ecology
Shelford’s Law of Tolerance (Shelford耐受性定律）：The
distribution of a species will be controlled by that environmental
factor for which the organism has the narrowest range of
tolerance. 物种的分布范围受忍耐性最窄的环境因子限制
（3）Adaptation 适应性
(i) A process of genetic change in a population whereby,
as a result of natural selection, the average state of a
character becomes improved with reference to a
specific function, or
whereby a population is thought to have become
better suited to some feature of its environment.
(ii) Also, an adaptation: a feature that has become
prevalent in a population because of a selective
advantage conveyed by that feature in the improvement
in some function.
剪谷颖
（4）Habitat Selection 生境选择
寻觅寄主
找到寄主
交配
评价寄主
羽化
产卵
结茧
爬出幼虫
卵和幼虫发育
迁徙鸟的生
境选择
Applications: Rarity and Extinction
(稀有和绝灭)
?
Three factors
Geographic range:
extensive
restricted
Habitat tolerance:
broad
narrow
Large
small
Local population size:
Most common
Rarest
7 combinations – rarity; 1 combination - common
思考题
1. 假设你在沙漠中发现了一种新蜥蜴，如何描述它的生境？
如何研究其生境范围？
2. 环境结构（如土壤类型和土壤湿度的分布）对植物的分
布格局有何影响？植物间的相互作用是如何影响其分布
格局的？
3. 有2种植物，一种是以种籽繁殖的，种籽随风传播；另
一种无性繁殖，靠枝蔓发芽繁殖。这两种繁殖方式对其
分布格局有何影响？
课堂作业
选择2个坐标图，概括出其所表达的结果或结论。