Transcript BIO100 KEY CONCEPTS-INTRODUCTION-

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, 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 (sometime astronomical) factors
Major Ecosystem Interactions
• Energy production, transfer, and loss
– Photosynthesis makes food, then one organisms eats
another
• Nutrient movement
– uptake, transfer, and recycling of nutrients.
• Tolerance, competition, predation
– What can organism handle, how well does it obtain
resources, what eats it and to what extent
• Ecological Succession
– Change in community over time
• Symbiosis: very/unusually close relationships among organism
Energy & Nutrients
• Usable energy created by photosynthesis from energy of sun.
• Energy and nutrients pass from one organism to the next through feeding
• Energy is lost, but nutrients cycle
sun
Energy & Nutrients
• nutrients pass from one organism to the next through feeding and are
then cycled back through the ecosystem
Major Ecosystem Interactions
• Ecological Succession
– Change in community over time
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
xx
Symbiot (smaller)
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?
Major Concepts
• Tolerance:
– The amount of a physical condition that an organism can
tolerate/live with
• Competition:
– How good is it at getting resources compared to other
individuals or organisms/species
• Predation:
– What eats/kills it and at what level
• Adaptation:
– A characteristic that makes an organism better suited to its
environement
• better able to tolerate, compete, be a predator or escape
predation, and reproduce
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
• Same species
• 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
The brownbarnacle competitively excludes the gray barnacle from the lower
area even though the gray barnacle could tolerate that area
Tolerance
ranges
Area
found
Distribution of Living Organisms
across the landscape is determined by a combination of
(things are where they are because):
• 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 (where things are found)
Found in this range
• Intolerant (too little)
• Predation
• Out competed
• Intolerant (too much)
• Predation
• Out competed
The Rocky Shore
TIDAL ZONES
Highest
Not generally covered by water; gets splashed and sprayed
•
Intertidal
Zone
Covered and exposed once daily
•
Lowest
Covered and exposed twice daily
Subtidal
Exposed only at negative tides
Never exposed
PHYSICAL GRADIENTS OF TIDE ZONES
1. WAVE SURGE/SHOCK
No wave surge/shock
2. WATER
Dryer
Significant
wave shock
subtidal
Less wave shock
Wetter
OTHER VARIABLES
• Temperature
– increases with exposure and time
• Salinity
– Increases with exposure and time
– Can decrease during exposure with rain
• Oxygen
– decreases with exposure time
• Restricted Feeding
– Ability to feed and availability of nutrients decreases with
exposure.
• Limited Space
– Wet places and other refuges are in limited when tide is
out
ZONATION
• Physical Zonation  Biological Zonation
• The existence of characteristic communities
at the different tide zones
• Based on:
– Tolerance to physical factors (usually sets upper
limit)
– Competition (competitive exclusion) and
Predation (usually sets lower limit)
Biological Zonation
Terrestrial Environments:
it all begins with plants
Terrestrial Environments:
it all begins with plants
THE CENTRAL IMPORTANCE OF PLANTS
(and many producers)
• They form the base of the food chain
– Biologically available energy and nutrients originate from
plants
• Plants cannot move (animals can).
– Thus 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
– Via habitat structure and food availability (type and
amount)
• Terrestrial ecosystems/communities are usually
identified by the plants groups they posses.
HOW PLANTS WORK
• Use Water, CO2, and sunlight energy to make food (photosynthesis)
• This happens mostly in leaves (which collect sunlight and CO2)
– WATER + CO2  SUGARS
HOW PLANTS WORK
• Plants loose water through leaves
• Some of this is necessary to get water to leaves for photosynthesis
– But too much water loss is bad
Abiotic (non-living) factors affecting the
distribution of organisms
• Temperature
• Water
Large Scale
• Sunlight
• Wind
• Soil Conditions
– pH
– salt content/salinity
– sandy
– tightly packed
– organic content
Small Scale
HOW PLANTS WORK
• Reproduction: plants do it with animals or the wind…or
water
How Plants Work
• Seeds (with embryo) are dispersed
Asexual Reproduction in Plants
How plants obtain resources
• Obtaining water:
– from soil (except aquatic plants) by roots.
– lose water through leaves, but some water loss is required
to move it.
– roots get it, leaves lose it.
• Obtaining Sun:
– Leaves
• Obtaining carbon dioxide:
– from leaves pores called stomata, but letting CO2 in allows
water to exit.
PLANT REPRODUCTION
• Sexual Reproduction (flowers, cones, spores, etc)
• Since plants can’t move:
– their sperm needs to disperse to eggs
• animal pollinators, wind, or water)
– offspring (seeds and spores) need to disperse
away from parents
• by animals, wind, water, or “explosive propulsion”
• Asexual (roots, stem base, runners, fragments)
– Alternative reproduction includes self-fertilizing and
vegetative propagation (cloning).
Extra or Reference Slides
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:
–
–
–
–
–
–
–
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)
ADAPTATIONS to Rocky Shore Env.
• To Exposure/Drying
–
–
–
–
“run and hide”
“clam up”
Tolerant of drying
aggregation
• To Temperature Increases
– Physiology/morphology
– color
– “run and hide”
• To Salinity Changes
– Physiology
– “clam up”
• To Wave Shock
–
–
–
–
–
–
“run and hide”
Low profile
Aggregation
“hold on tight”
Shells
“go with the flow”--bending
FORAGING MODES
• Photosynthesis--make their own food with sunlight energy
– Algae (free living and endosymbiots)
• Filter-feeders – filter/strain food out of water
– Made possible by movement of nutrient rich water—currents and tide
– shell fish/mollusks, barnacles, sponges, tunicates, tube worms
• Sessile predators – immobile, but actively capture prey
– Made possible by movement of nutrient rich water—currents and tide
– e.g., anemones,
• Grazers – mobile algae eating organisms
– snails, chitons, urchins, Sea hairs, some crabs
• Active/Mobile predators – move and eat other animals
– Sea Stars, some snails/molluscs, some crabs/lobsters, some fish,
• Scavengers/Detrivores—eat non-living things and stuff that
settles on bottom
– Lobsters, Crabs, rock lice/sea roaches
MARINE FOOD CHAINS
• Photosynthetic Producers
– Mostly phytoplankton, but some multicellular algae
•
•
•
•
Zooplankton
Primary Consumers
Secondary Consumers
Scavengers/decomposers
Algae/Kelp
• Photosynthetic, but not plants
• Different groups based on colors
• Because they are in the inaccessible subtidal zone, often they
are best examined when washed up on shore