Transcript BIO100 KEY CONCEPTS, altitude effects, plants and Hwy 2 (post

Biology & Geology 100
• Introduction to key biological concepts
• Background for tomorrow’s field trip
What is Natural History?
• the study of the natural environment with an
emphasis on identification, formation/origin
of physical features, life-history, distribution,
abundance, and inter-relationships.
– It often and appropriately includes an aesthetic
component.
The Natural Environment=Ecosystems
• An interacting unit of living and non-living
components.
– Living Things (biotic)
• Plants, algae, animals, fungi, microbes
• All the living things of an area = community
– Non-living things (abiotic)—the physical environment
• Water, temperature/heat, sunlight, wind/air, soil/minerals,
nutrients (found in air, water, & soil) etc…
– Created by geological (sometimes astronomical) factors
The Natural Environment = Ecosystems:
An interacting unit of living and non-living components
Abiotic = non-living
• Sunlight & Heat
• Air
• Water
• Earth
(minerals/soil)
Biotic = living
• Animals
• Plants
• Algae
• Microbes
Biological Factors
Physical Factors
Homage to Geology
• Geological forces creates diversity in
landscape and abiotic variability
• Variation in the physical landscape  habitat
diversity  habitat diversity  biological
diversity
– opportunity for different forms of life to evolve
and co-exist
Major Ecosystem Interactions
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Energy production, transfer, and loss
Nutrient movement
Tolerance
competition
predation
Symbiosis
Ecological Succession
Food
WebsTransfer
= energy =and
nutrient
movement
Energy
food
chains/webs
Sun = initial
source of energy
Producers:
--Plants
--algae
Herbivores
carnivores
consumers
Decomposers:
--fungi
--bacteria
Interactions and flow within an ecosystem
Nutrient Cycling: an example showing interactions between
physical environment and living things
• nutrients pass from one organism to the next through feeding and are then
cycled back through the ecosystem
Tolerance Ranges
• For every physical aspect of the environment
and for every substance used by an organism :
– (e.g., temperature, water, wind, minerals, nutrients, pH, etc):
– There is a minimum amount needed and a maximum
amount that can be tolerated.
– Between the minimum needed and maximum
tolerable is the “tolerance range)
Tolerance range
a simple schematic
too dry
Tolerance range
for the grass to
survive
there is enough to meet the grasses
needs, but not too much
too wet
for the grass to
survive
water
wet
dry
Competition
Competition for:
• Food
• Shelter
• Light
• water
• space
• Mates
Competition happens:
• Between individuals of same
species
• Between different species
– Competitive exclusion
• Influences where organisms
are located
Competitive Exclusion
• Two species that compete for the same resources in
the same way cannot coexist long term
– The species that is the better competitor (in a
given environment) will exclude the other specie
at that location this is competitive exclusion
Tolerance range + Competition
a simple schematic
Limit due to tolerance
Limit due to competition =
competitive exclusion
too dry
Tolerance range
for “grass”
Bush is better
competitor in this
area; excludes grass
water
wet
dry
Predation
• One thing eats another (e.g., one consumer eats another)
• Energy and nutrient acquisition
seal
Distribution of Living Organisms:
across the landscape is determined by a combination of
(things are where they are because) the following
• Physical factors
– specifically tolerance to physical factors and
availability of abiotic resources
• Competition
• Predation
• Dispersal
– has the organism been able to get to an area from its existing range
Common Factors Determining Distribution
(i.e., where things are found)
Found in this range
• Intolerant (too much)
• Predation
• Out competed
• Intolerant (too little)
• Predation
• Out competed
Also dispersal: is the organism or its offspring able to get to an area. If the organism is incapable
of reaching an area (or has not yet reached an area) then it won’t be found there.
barrier to dispersal (no lizards here)
• Intolerant (too little)
• Predation
• Out competed
• Intolerant (too much)
• Predation
• Out competed
Major Ecosystem Interactions
• Symbiosis: very/unusually close relationships among organism
Symbiosis
• Particularly close relationships between two or more
organisms
– Often (but not always) refers to situation when one
organism lives in or on another organism
Host (bigger)
• Mutualism
• Commensalism
• Parasitism
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Symbiot (smaller)
• Adaptation:
– A characteristic that makes an organism better suited to its
environment
• better able to tolerate, compete, be a predator or escape
predation, and reproduce
Our Goal = biologically interpret/assess
1. Why is this place the way it is; why are the
things that are here, here?
2. What can I tell about this place from what I
see?
Niche
• The role an organism plays in its environment
• How an organism “makes its living”.
• All the ways a species uses its physical
environment/resources and all its interactions with
other living things.
• Examples of what a niche contains:
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What it eats
When it eats
How it gets food
What eats it
When is it active
What wastes does it put back into the environment
What resources it needs (nutrients, space, shelter, etc)
Terrestrial Environments:
it all begins with plants
Terrestrial Environments:
it all begins with plants (or some other producer)
THE CENTRAL IMPORTANCE OF PLANTS
(and many producers)
• They form the base of the food chain
• Plants cannot move (animals can).
– they are reflective of the physical conditions at a particular area.
• The type of plants in a location influences the type
of animals at that same location
• Terrestrial ecosystems/communities are usually
identified by the plants groups they posses.
What is a community
• A group of species that grow together in sites
that are environmentally similar
• They exist together because:
– they have similar tolerance ranges
– They inhabit different niches
• Don’t compete too directly
HOW PLANTS WORK
• Water (from soil) + CO2 (from air) + Sunlight  Sugars
photosynthesis
• This happens mostly in leaves
HOW PLANTS WORK pt 2
• Plants loose water through leaves
• They have to lose water to move water.
– necessary to get water to leaves for photosynthesis
– But too much water loss is bad
Leaves are compromises between:
Water loss
photosynthesis
HOW PLANTS REPRODUCE
• plants do it with animals or the wind…or water
How Plants Work
• Seeds (with embryo) are dispersed
Asexual Reproduction in Plants:
some plants do it by themselves
Plant Reproduction:
asexual v. sexual
ASEXUAL
SEXUAL
• Fast
• Cheap/low energy
• Easy
• Slower
• Takes more energy
• More risky
BUT
• Produces offspring that are
identical to parent
BUT
• Produces variable offspring
that could be better
adapted to current or future
conditions
Abiotic (non-living) factors affecting the
distribution of plants & plant communities
• Temperature
• Water
Large Scale
• Sunlight
• Wind
• Soil Conditions
– pH
– salt content/salinity
– sandy
– tightly packed
– organic content
– Slope aspect
Small Scale
Water
Availability
Productive
Temperature
Photosynthesis and
Growth
Right temp and water amount  photosynthesis  food  growth and reproduction
“productivity”
Within a zone, there is further fine scale
variation based on:
• small scale differences in water
– (creeks, ponds, slope aspect, etc…)
– create Riparian zones
• temperature
– (depressions, slope aspect)
• sunlight
– (clearings, slope aspect, canopy shading)
• soil
– (pH, sandy, gravelly, salinity, mineral, organic, nutrient levels, etc..)
• wind
– (exposed or protected)
Increasing Altitude =
• Decreasing Temperature (~3 deg. F per 1000’)
• More rain/water (precipitation, but….)
• Shorter growing seasons
Colder
Hotter
Slope Aspect: North v. South
Slope Aspect: east v. west
Chaparral Biome
Mediterranean Climate & Chaparra Biome
• Mid-latitude (30 deg), coastal regions
• Sea level – ~5500’
• Seasonal precipitation
– Precipitation 8-20”, mostly in winter (Dec – Mar)
– Prolonged period of drought (~Apr-Nov)
– Rain/precipitation highly variable from year to year.
• Seasonal Temperatures
– long dry summers 80-100+ F
– spring, winter, fall cool
– winters moderately cold in coastal regions, but higher elevation can
experience frost and small amounts of snow
In more coastal regions:
• Santa Ana winds in summer (hot and dry)
• fog, mist, marine layer in some seasons
Common Communities of the Mediterranean Climate in So.CA
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Sage scrub
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Closer to coast, lower elevations
8-10” of rain per year, but with moderate temperatures
sub-shrub dominant
drought deciduous
frost intolerant
Types
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Coastal
• Inland
• succulant
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Chaparral (true/hard chaparral)
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More inland, higher elevations
Wetter (~15-20” of rain)
shrub dominant
Generally evergreen dominant
frost tolerant – snow tolerant
Types:
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Lower v. Upper v. maritime v. desert
Chamise v. mixed
Oak woodland
Riparian
– Mesic community in canyon bottoms (and where water is more abundant)
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Grassland
Conifer Forest
Hwy 2 Field trip
• Changes with altitude
• Changes with slope aspect
• Changes due to localized water availability—
i.e., permanent water/streams
• Effects of fire?