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ECOLOGY
Another dimension of Biodiversity is how
recognizable associations of organisms
inhabit the same place – as ecosystems
Understanding these associations is the subject of Ecology
For example, coral reefs are distinctive aggregations of
species found on some tropical coastlines.
The reefs themselves are built by animals
- the reef building corals (Phylum Cnidaria, Class
Anthozoa, Order Scleractinia)
- photosynthesize (via endosymbiotic cyanobacteria),
also feed on small animals in water (zooplankton)
- grow clonally, “plant-like”
- deposit a bone-like calcium carbonate (CaCO3)
structure – keeps them near surface – the “reef”
Can build huge “shelves” of coral offshore – “barrier reefs”
Or other forms, e.g. Atolls
This animation shows the dynamic process of coral atoll formation. Corals (represented in tan
and purple) settle and grow around an oceanic island, forming a fringing reef. In favorable
conditions, the reef will expand, and the interior island will subside. Eventually the island
completely subsides beneath the water, leaving a ring of growing coral with an open lagoon in its
center. The process of atoll formation may take as long as 30,000,000 years to occur.
http://en.wikipedia.org/wiki/Atoll
Coral reef systems are
very diverse – many
other species live in
and around reef
Various reef systems around the world, contain different species,
but similar mixes of types – readily classified as “coral reefs”
Some contribute to reef building (Corraline Algae), some
just live there (shrimp, crabs, fish), some even eat coral
and damage the reef (Polychaetes, sponges, starfish). If
this is a “system”, what kind of system is it?
Nice tour: http://www.biosbcc.net/ocean/marinesci/04benthon/crzone.htm
In other tropical coastal areas – Mangrove swamps
- coastal forests, held together by tree roots
- specialized salt water tolerant trees
- diverse & unique aquatic & terrestrial community
- Mangrove not a taxonomic group, various groups – all
“converged” on similar adaptations – e.g. “_____________”
- Mangrove systems throughout the world, different species,
similar mix of types – readily classified as “Mangroves”
Red – coral reefs, Green – Mangroves, Blue – Lakes, Rivers, Ocean
Bare rock shores
- “rocky intertidal” system
- “simple” communities, few species
- seaweeds (algae), barnacles, mussels, snails, starfish
- tidal “________”, tide pools
Rocky intertidal systems worldwide, similar but different species
Coastal Salt Marshes
- river enters sea – “estuaries”, mix of salt and freshwater
- extensive stands of plants, many organisms
Open Ocean
Deep Sea
Fresh Water systems
Rivers, streams, lakes, ponds, marshes
By the way, why ARE oceans salty?
The hydrologic cycle- Water evaporates, leaves salt behind
Salts are dissolved ions
Ions come from ____ weathered by rain
2.2 lbs of it for every cubic foot of seawater
(taken out and spread across land – 500 ft thick)
- So should be all kinds of stuff in seawater (there is, but most in
very small amounts, e.g. gold)
- Should be like concentrated ______ water – but it’s not – why?
>85% is sodium & chloride (Na+,Cl-) – table salt, also (Mg, S, K)
- Life alters ocean chemistry - organisms remove a bunch of things
but NOT NaCl (Ca - Foramnifera, Si - Diatoms)
http://www.palomar.edu/oceanography/salty_ocean.htm
Of course we went for a float in the water. This is a must
do for anyone coming to Israel. The water in the Dead Sea
is some 5x more salty than sea water. In addition, it is
laden with many other minerals. The Israelis claim
soaking in its waters is healthy and is a good treatment for
any skin problem. When you climb in, you can feel the
buoyancy immediately. You feel oily and realize that
you're not walking over sand but salt. It tastes really bad
and you can see minerals precipitating out of the water.
Along the beach is a white crust of salt. We drove for a
while down the other side of the sea where they harvest
the minerals and it actually makes the water look pretty
disgusting. Anyway the water is incredibly buoyant.
Everyone just floats on top of the water. It's so buoyant
that you can spin or lift your leg out of the water. You're
only supposed to soak 20-30 minutes so we also did some
quality lazing on the beach which was a nice break. There
was the guy who panicked in knee deep water and thought
he was drowning until he stood up ... in knee high water.
The new sensation of super buoyancy was a blast and the
most fun I have had wading about in years. It made me
feel like a little kid again – Michael Kan
http://www.kan.org/michael/mideast/mideast3.html
Salt important for
currents – affect
________, salinity
varies across globe
(but composition
constant, variable
concentration)
Global warming
increasing tropical
salinity – higher
evaporation, affect
ocean currents
http://www.whoi.edu/institutes/occi/currenttopics/abruptclimate_rcurry_pr_en1.html
Terrestrial Systems
Deserts
Grasslands
Forests
Patterns – simple questions
- diverse species
why so many? why not just one?
- species limited in distribution
why here, not there? why not same species everywhere?
- mixture of kinds of species (bacteria, plants, fungi, animals)
how do they coexist, interact?
- characteristic assemblages (convergence) – different species,
but similar
why particular associations?
- found in similar types of places, similar climates
what is role of environment?
What is “Ecology”?
The study of biological organization “at and above the level of
the organism”. (one definition)
Ecology
What are “__________________”?
Biosphere
Ecosystem
Community
Population
Organism
Organ
Tissue
Cell
Organelle
Molecule
2-7
Ecosystem
Community
Population 1
Abiotic Environment
Light, nutrients,
substrate, etc.
Pop 2
Pop 3 etc.
Organism (sp. 1)
2
3
Peel the Orange
So “_________” refers to all the
Organisms of different species living in
the same place as well as the non-living
part of the Environment they utilize and
live in. The organisms exist as
___________ – multiple members of a
species, that interact with other
populations to form a ________ – the
array of interacting populations in a place.
Ecosystem
Community
Pop 1
Pop 2
Abiotic
Environment
Pop 3
Ecosystems not clearly bounded,
generally linked to each other
The Biosphere is the aggregate of
all linked ecosystems of the earth.
The term ______ refers
to widespread ecosystem
types (generally
terrestrial) such as
“deserts”, “grasslands”
etc. So “biome” is more
of a category rather than
a “real” thing.
The equivalent in
aquatic systems is
___________ (such
as lakes, streams,
open ocean, coral
reefs, estuaries, etc.)
3-5/3-6
Ecologists study emergent properties of all these levels
Biosphere
Organism – ___________, time budget
Ecosystem
Population – growth rate, carrying capacity
Community
Community – diversity, ___________
Population
Ecosystem – _________, nutrient cycling
Organism
Biosphere – ____________, atmosphere
Organ
Tissue
Study at any particular level
Cell
usually requires simplification of
Organelle
the lower/deeper levels
Molecule
_____________ is studied at multiple levels
genetic (population), species (community), functional
(ecosystem), habitat (“landscape”, biosphere)
Organisms
Organisms are “organized” for ecological success
Genomes, organ systems, physiology,
growth, behavior, etc. are highly integrated
to serve the survival and reproduction of
the ________________ (fitness).
Organisms
Predator senses
Organisms
Prey defenses
Organisms
Plants in the desert are adapted to reduce water loss
Or no leaves
Small, thick leaves
Or store it
Organisms
Many desert animals (esp. seed eaters) never drink
Various adaptations to reduce water loss (reduced
urine, feces, etc.) But where do they get it?
Read more: http://www.desertusa.com/survive.html
Organisms
Integrated organisms, the autocatalysts, are the basic
components of processes at the higher levels.
Analogous to “individuals” in economic theory.
Individuals determine processes at higher levels – but
they don’t, can’t, exist ________________
Populations
What “organizes” biology above the level of the organism?
At the population level – mainly ______________________.
Population – all the individuals of the same species in the same
place, generally with the potential to ____________________.
_______ – the sum of all populations of a species
– defines the distribution of a species in space.
Populations
Populations are _________ – inputs and outputs
Population growth = Inputs (births, immigrants)
– outputs (emigrants, deaths)
Growth has ___________ potential, but growth _______
as population increases – “carrying capacity”
Carrying capacity
- Competition
resource depletion
agonistic interactions
- Increased enemies
- “density dependent”
4-7/4-5
Density ____________factors
- Real populations bounce around a lot, within bounds
- Environmental fluctuations – climate, food, enemies
- Can lead to population extinction, esp. small pops
Populations
Population regulation important for _____________
- species extinction, protection – “_________”
- species introductions – “_____________”
- species harvest – “________________ yield”
Harvest – growth curves imply maximum growth at
____________ population densities
- too low, few individuals to reproduce,
despite high reproductive capacity
- too many (near carrying capacity), low
reproductive capacity per individual.
Pop
Growth
Density
Populations
________________ – populations distributed in space
Population viability may
depend on other nearby
populations that share
migrants
“Sources” vs. “Sinks” - any particular population
may appear healthy, but may depend on healthier
population nearby.
Populations
Sociality
In animals, populations may be subdivided into social groups
Key feature – ___________ – conspecifics (members of the
same species) acting in concert to increase success (fitness).
“____________ amongst competitors” – helping behaviors
evolve through direct benefits and reproductive benefits
Two main benefits – _________ and _________
often social groups benefit in both
temporary or permanent
often internal structure
- dominance hierarchies
- “eusociality” – caste systems
Populations
_________ gathering
Safety in ____________
Flocks, herds
Populations
Cooperative hunting
Populations
Food ________
Social ____________
Defense against ____________
Role differentiation – _________ hierarchies
http://www.discoverlife.org/ap/
Populations
Role differentiation
Eusocial _________ – queens, workers, soldiers
Populations
The Niche Concept
Goal - to understand the distribution and abundance of individuals of a
species (populations) in space and time (another definition of ecology)
Traits of each species determine success or failure
The characteristics of the environment where a particular species
succeeds define its niche – includes both _____ and _____ components
Climate (temperature, moisture, etc.)
Resources (food, reproductive sites, etc.)
Predators, diseases, etc.
Major idea – Niche – ecological limits of a species - map
of organisms in physical space/time to ________________
Populations
2-12/2-13
Populations
Niches are measured and depicted graphically on niche axes
axis – dimension of ecological space
Niches may be
broad, narrow,
overlapping,
Axis B
and _______________
Axis A
Precipitation
Populations
Temperature
Populations
The niche of a given species is
also shaped by interactions with
_______________ can limit the
niche
“MacArthur’s Warblers” – classic
example of similar species utilizing
similar habitat. Competition
between individuals of different
species possible.
4-3/4-1
Populations/Communities
Similar species can co-exist more readily if they
utilize different portions of shared niche axes
– have different niches (determined by traits)
Coastal wetland
So, an organism’s integrated traits (genes) allow success or
determine failure of a population in any particular ecosystem
Both the possibilities and limits for survival