biology 205 3
TRANSCRIPT
Biology 205Biology 205Ecology and AdaptationEcology and Adaptation
Lecture 3: Life on LandLecture 3: Life on Land
Dr. Erik D. DavenportDr. Erik D. Davenport
Class outline
Review Why are there many different biomes on the Why are there many different biomes on the
Earth? Earth? Climate diagram.Climate diagram. Major biomes on the land --- characteristics Major biomes on the land --- characteristics
and distribution.and distribution.
Review
What is ecology?
What is the scope of Ecology?
BiomesBiomes
– The areas on the earth that are distinguished primarily The areas on the earth that are distinguished primarily by their predominated plant and are associated with by their predominated plant and are associated with particular climates.particular climates.
– Such as Such as tropical rain forest biometropical rain forest biome, or , or desert biomedesert biome..
Why are there many different biomes on the Why are there many different biomes on the Earth?Earth?
--- Climate (environmental conditions) on the --- Climate (environmental conditions) on the Earth is not the same everywhere.Earth is not the same everywhere.
Each biome --- specific climateEach biome --- specific climate
Climate factors on LandClimate factors on Land
TemperatureTemperature
Rainfall (water)Rainfall (water)
SeasonSeason
Sun!!!!! – energy sourceSun!!!!! – energy source
Solar radiation is the sole energy source for Solar radiation is the sole energy source for all the organisms on the earth.all the organisms on the earth.
However, the radiation from sun is not However, the radiation from sun is not equally distributed on the earth. Why?equally distributed on the earth. Why?
Spherical shape of The earthSpherical shape of The earth
--- spherical shape of the earth causes --Different area on the Earth receives different amount of solar energy--- uneven heating –
-- temperature difference
Temperature, AtmosphericTemperature, Atmospheric Circulation, and Precipitation Circulation, and Precipitation
Temperature then drives air circulation Temperature then drives air circulation patterns and consequently precipitation patterns and consequently precipitation patterns.patterns.– Warm, moist air rises, Cools, condenses, and falls Warm, moist air rises, Cools, condenses, and falls
as rain.as rain.– Cooler, dry air falls back to surface.Cooler, dry air falls back to surface.
Rainforests found near equator.Rainforests found near equator. Major deserts found near 30Major deserts found near 30oo N / S. N / S.
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Solar-driven, latitude and atmospheric circulationFigure 2.5
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Why tilted axis is also important?-- seasons!!!
Earth tilted rotation axis
Earth rotation plainAround the sun.
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Seasons in Northern and Southern hemispheres
What factors contribute to the variation in What factors contribute to the variation in climate on the earth?climate on the earth?
Uneven heating of the earthUneven heating of the earth’’s spherical s spherical surface by the sunsurface by the sun and and the tilt of the earth on the tilt of the earth on its axisits axis combine to produce the predictive combine to produce the predictive latitudinal variation in climate.latitudinal variation in climate.
The geographic distribution of terrestrial The geographic distribution of terrestrial biomes corresponds closely to variation in biomes corresponds closely to variation in climate, especially the prevailing temperature climate, especially the prevailing temperature and precipitation.and precipitation.
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Something Extra but interesting•Coriolis effect causes apparent deflection of winds clockwise in the N hemisphere and counterclockwise in the S hemisphere.
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Structure of climate diagramsFigure 2.7
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Climate DiagramsClimate Diagrams
Summarize climatic information using a Summarize climatic information using a standardized structure.standardized structure.– Temperature plotted on left vertical axis.Temperature plotted on left vertical axis.– Precipitation plotted on right vertical axis.Precipitation plotted on right vertical axis.– 1010oo C equivalent to 20 mm precipitation. C equivalent to 20 mm precipitation.– Relative position of lines reflect water availability.Relative position of lines reflect water availability.– Adequate moisture for plant growth when Adequate moisture for plant growth when
precipitation above temperature.precipitation above temperature.
Climate diagramClimate diagram
Is a tool to explore the relationship between Is a tool to explore the relationship between the distribution of terrestrial vegetation and the distribution of terrestrial vegetation and climate.climate.– Seasonal variation of temperature and Seasonal variation of temperature and
precipitation. precipitation. – The length and intensity of wet and dry season.The length and intensity of wet and dry season.– The portion of the year during which average The portion of the year during which average
minimum temperature is above and below zero.minimum temperature is above and below zero.
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Climate diagram for a rain forestFigure 2.8
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Climate diagram for a hot desertFigure 2.8
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Tropical Rain forest Tropical Rain forest
Trees dominate the tropical rain forest, with average height of 40 m
Tropical Rain forestsTropical Rain forests
Most occur within 10Most occur within 10oo latitude of equator. latitude of equator. Little temperature variation between months.Little temperature variation between months. Annual rainfall of 2,000 - 4,000 mm relatively Annual rainfall of 2,000 - 4,000 mm relatively
evenly distributed.evenly distributed.– Quickly leaches soil nutrients.Quickly leaches soil nutrients.– Mycorrhizae Mycorrhizae help gather nutrients (Epiphytie mat).help gather nutrients (Epiphytie mat).
Organisms add vertical dimension.Organisms add vertical dimension. Harbor staple foods and medicines for worldHarbor staple foods and medicines for world’’s s
human populations - increasingly exploited.human populations - increasingly exploited.
Tropical dry forestTropical dry forest
Tropical Dry ForestTropical Dry Forest
Usually located between 10Usually located between 10oo - 25 - 25oo latitude. latitude. Climate more seasonal than tropical rainforest.Climate more seasonal than tropical rainforest. Soils generally richer in nutrients, but vulnerable Soils generally richer in nutrients, but vulnerable
to erosion.to erosion. Shares many animal and plant species with Shares many animal and plant species with
tropical rainforests.tropical rainforests. Heavily settled by humans with extensive Heavily settled by humans with extensive
clearing for agriculture.clearing for agriculture.
Tropical SavannaTropical Savanna
Tropical SavannaTropical Savanna
Most occur north and south of tropical dry Most occur north and south of tropical dry forests within 10forests within 10oo - 20 - 20oo of the equator. of the equator.
Climate alternates between wet / dry seasons.Climate alternates between wet / dry seasons.– Drought associated with dry season leads to Drought associated with dry season leads to
lightning-caused wildfires.lightning-caused wildfires. Soils have low water permeability.Soils have low water permeability.
– Saturated soils keeps trees out.Saturated soils keeps trees out. Landscape is more two-dimensional with Landscape is more two-dimensional with
increasing pressure to produce livestock.increasing pressure to produce livestock.
DesertDesert
DesertDesert
Major bands at 30Major bands at 30oo N and 30 N and 30oo S latitude. S latitude.– Occupy about 20% of earthOccupy about 20% of earth’’s land surface.s land surface.
Water loss usually exceeds precipitation.Water loss usually exceeds precipitation. Soil usually extremely low in organic matter.Soil usually extremely low in organic matter. Plant cover ranges from sparse to absent.Plant cover ranges from sparse to absent. Animal abundance low, but biodiversity may be high.Animal abundance low, but biodiversity may be high.
– Strong behavioral adaptations.Strong behavioral adaptations. Human intrusion increasing.Human intrusion increasing.
Temperate Woodland and shrublandTemperate Woodland and shrubland
Temperate Woodland and Temperate Woodland and ShrublandShrubland
Occur in all continents except Antarctica.Occur in all continents except Antarctica. Climate cool and moist in fall, winter, and spring, Climate cool and moist in fall, winter, and spring,
but can be hot and dry in summer.but can be hot and dry in summer. Fragile soils with moderate fertility.Fragile soils with moderate fertility. Trees and shrubs typically evergreen.Trees and shrubs typically evergreen. Fire-resistant plants due to fire regime.Fire-resistant plants due to fire regime. Long history of human intrusion.Long history of human intrusion.
– Cleared for agriculture.Cleared for agriculture.
Temperate GrasslandTemperate Grassland
Temperate GrasslandTemperate Grassland
Extremely widespread distribution.Extremely widespread distribution. Annual rainfall 300 - 1,000 mm.Annual rainfall 300 - 1,000 mm. Experience periodic droughts.Experience periodic droughts. Soils tend extremely nutrient rich and deep.Soils tend extremely nutrient rich and deep. Thoroughly dominated by herbaceous Thoroughly dominated by herbaceous
vegetation.vegetation. Large roaming ungulates.Large roaming ungulates.
– Bison vs. cattleBison vs. cattle
Temperate Forest (Old Growth)Temperate Forest (Old Growth)
Temperate Forest (Old Growth)Temperate Forest (Old Growth)
Majority lie between 40Majority lie between 40oo and 50 and 50oo latitude. latitude. Rainfall averages 650 - 3,000 mm.Rainfall averages 650 - 3,000 mm. Fertile soilsFertile soils
– Long growing seasons dominated by deciduous Long growing seasons dominated by deciduous plants.plants.
– Short growing seasons dominated by conifers.Short growing seasons dominated by conifers. Biomass production can be very high.Biomass production can be very high. Many major human population centers.Many major human population centers.
Boreal Forest (Taiga)Boreal Forest (Taiga)
Boreal Forest (Taiga)Boreal Forest (Taiga)
Confined to Northern Hemisphere.Confined to Northern Hemisphere.– Covers 11% of earthCovers 11% of earth’’s land area.s land area.
Thin, acidic soils low in fertility.Thin, acidic soils low in fertility. Generally dominated by evergreen conifers.Generally dominated by evergreen conifers. Relatively high animal density.Relatively high animal density. Historically, low levels of human intrusion.Historically, low levels of human intrusion.
TundraTundra
TundraTundra
Covers most of lands north of Arctic Circle.Covers most of lands north of Arctic Circle.– Climate typically cool and dry with short summers.Climate typically cool and dry with short summers.
200 - 600 mm precipitation.200 - 600 mm precipitation.
Low decomposition rates.Low decomposition rates. Supports substantial numbers of native Supports substantial numbers of native
mammals.mammals. Human intrusion historically low, but Human intrusion historically low, but
increasing as resources become scarce.increasing as resources become scarce.
Mountains: Islands in the SkyMountains: Islands in the Sky
Mountains: Islands in the SkyMountains: Islands in the Sky
Built by geological processes and thus Built by geological processes and thus concentrated in belts of geological activity.concentrated in belts of geological activity.
Climate changes with elevation and latitude.Climate changes with elevation and latitude. Soils are generally well-drained and thin.Soils are generally well-drained and thin. Flora and fauna change with elevation.Flora and fauna change with elevation. Historically used as a source of raw materials Historically used as a source of raw materials
for human settlements.for human settlements.