Download Computational Ecology Intro. to Ecology

Computational Ecology
Introduction to Ecological
Science
Sonny Bleicher Ph.D.
Ecos
Logos
Defining Ecology
• Interactions:
• Organisms:
• Plants
• Animals:
•
•
•
•
Bacteria
Fungi
Invertebrates
Vertebrates
• The physical environment:
• Air:
• Gasses
• Water Vapor
• Water:
• H2O
• Ions
• Earth:
• Minerals
• Ground water
• Dissolved organic matter
But first what is a living organism?
• Reproduction
• Growth
• Metabolism
• Death
Scales of Study
From the individual to the biome
• The individual
Not a traditional, however at the
forefront of ecological research
• Micro-scale genetic makeup and
epigenetics affecting personality
and choices of individuals:
• Should an individual take risk (be
bold) or avoid risk?
• Is any mate a good mate for any
individual?
• Should an individual seed germinate
now, or wait for better conditions?
The population
A group of individuals of the same
species that inhabit the same space.
• How many individuals cans the
space(and resources) sustain?
• Demographics (distribution of
individuals between the sexes, age
classes).
• Life tradeoffs (where to invest
energy in reproductions (cost of
offspring, parental care, and time
of reproduction)
The Community
A number of populations of
difference species interacting in
the same space
• Interaction types :
• Predation (+, -) (and parasitism)
• Competition (-,-)
• Neutralism (0,0) (not fully an
interaction)
• Commensalism (+,0)
• Amesalism (-,0)
• Mutualism (+,+) (can also be
referred to as symbiosis if
persistent over long time)
The ecosystem
A community of organisms
interacting with each other and
with their environment such
that energy is exchanged and
system-level processes, such as
the cycling of elements, emerge.
• Focus predominantly on the
movement of the non-biological
elements, needed to sustain life,
movement in the environment:
•
•
•
•
•
Water
Energy
Carbon
Nitrogen
Phosphorus
Ecosystem (continued)
Ecosystem Services
• Ecosystem ecologists measure
system health using measures of
biological output, usually
translated into human economic
value:
• Biomass (lumber, crops, food).
• Gas production, and sequestration
(oxygenation of air, carbon
sequestration and fixing).
• System regeneration (water
filtration, pollutant sequestration
and absorbent).
• Climate regulation
Biomes:
The Biome: Macro-Ecology
• Study of the effects of climatic conditions on biological communities
and ecosystems.
• A study of convergent systems on a global scale.
Temporal Scales
Scale
Times
Individuals
Minutes-Days
Populations
Years-Decades (occasionally days )
Communities
Years – Centuries
Ecosystems-Biomes
Centuries-Millenia
Spatial Scale
Micro-Habitat
Habitat
Ecological Niche
Biome
Virtual Scale?
The Three Ecologists
The Theoretician – Modeler
The Empirical Ecologist
• Using observations and
computations to distill the laws
by which ecological interactions
occur.
• Using the natural conditions in
the field to test the modeler’s
laws and make observations.
• Based on the derived models,
making predictions and
designing management plans for
resources
The Conservation Ecologist
• Using the theories and
management plans, together
with the field experiment of the
empiricist to manage the
biological resources and
diversity.
Approaching Science:
World Views (Research Programs, Lakatos)
Ecological Research Programs
History of Life
Tools:
• All organisms evolved from
common ancestors.
• Tracing back the ancestors, and
identifying relative relatedness
can shed light on how species
interact and what are the
conservation needs of a species.
• Cladistics
• Phylogenies
• Genetic analysis
Ecological Research Programs
Diversity
Tools
• Taxonomy
• Systems with richer diversity are
more stable.
• Higher diversity means system
stability.
• High species richness allows for
less invasion by alien species.
• Genetic diversity testing (microbial)
• Diversity indices
• Diversity extrapolation and
estimation models
Ecological Research Programs
Optimization
• Competition for resources (energy, safety,
mates) drives all interactions in nature.
• All interacting species are in a constant
armament race against each other, the
losers go extinct.
• Thus, every physical and behavioural trait
must have (or have had) biological
benefit, and the cost of it must not be
grater than that of the benefits to the
current living organisms
The Red Queen responds: "Now, here, you
see, it takes all the running you can do to
keep in the same place"
Ecological Research Programs
Tools
• Mathematical models
• Manipulative field experiments
The greater ecological questions:
• Distribution: Where do we find species? And what are the resources
they need?
• Abundance: How many individuals can an area support ?
• Procession of life: What should an individual do at what age ?
• Fit of form and function: How do species use the resources in the
environment?
Why does this matter at all?
• The gene containment unit.
• Biological beings as computer
algorithms
• Survival of the code, not the
being.
How does that actually work?
• From the will to change
• To the forced constraints of the
environment.
Measuring Biological Success
The Jewish Mother Phenomenon
Fitness
Factors impacting fitness
• Energy
1 ∆𝑁
𝑁 ∆𝑡
• Mate Quality
• Offspring survivorship
• (the all encompassing power)
From Fitness, through Evolution
to Ecological Systems
• Species in a community compete for resources
• Each resource can sustain multiple species as long the strategies,
extraction methods, they use do not overlap.
• Species constantly change their strategies, however balance on the
strategy where any change would result in lower fitness, a point
called an evolutionary stable strategy (Maynard-Smith and Price,
1973).
Individual 2
Individual 1 Aggressive
Submissive
Aggressive
Submissive
(-1, -1)
(2,0)
(0,2)
(1,1)
Individual 2
Individual 1 Aggressive
Submissive
Aggressive
Submissive
(-1, -1)
(2,0)
(0,2)
(1,1)
Some Basic Concepts In
Ecology
In the time we have left
Population Dynamics – First and second laws
of ecology
1. Every population has the intrinsic potential to grow exponentially.
2. No population can grow exponentially without resource limitations.
Lotka-Volterra Competition Equations
Predator-Prey Limiting Cycles
Diversity
• Species Richness – The Number of species that are found in a system
• Species Diversity – A variable of the number of species in a system
with a relative abundance of that species out of the total number of
individuals measured.
Whittaker’s Diversities
• α–diversity: Local scale (in a specific plot)
• β-diversity: Between plots (relative)
• ϒ-diversity: Overall diversity in the landscape = α*β
Island Biogeography (McArthur and Wilson,
1967)
SLOSS – Debate (Jared Diamond, 1975)
• Do we make on large nature preserve (ex. The Maasai Mara )
• Or do we have many smaller reserves that protect smaller resource
hot spots.
Intermediate Disturbance Hypothesis
(Wilkinson 1999)
Holling’s Panarchy (2001)
Let’s test our understanding with actual
examples
• What research program would the research question fit in?
• How would results of such studies look like?
A couple of examples of ecological research
Effects of land management on ant
assemblages
35
30
Species Richness
25
20
15
10
Grazing+Logging
Grazing
5
Logging
Control
0
1
2
3
4
5
6
7
8
9
10
11
12
13 14
Samples
15
16
17
18
19
20
21
22
23
24
25
26
Effects of predation risk by vipers and owls on
gerbils and heteromyids
• Is the effect of multiple predators cumulative on desert rodents or do
rodents respond to the risk posed only by the greater feared
predator?
The Model (optimal patch use theory
𝐻 = 𝐶 + 𝑃 + 𝑀𝑂𝐶
)
(Brown 1988)
Divergent Behaviours
3
2.5
GUD (g) Owl
2
1.5
1
G. andersoni allenbyi
G. Pyramidum
C. Penicillatus
D. Merriami
0.5
0
0
0.5
1
1.5
GUD (g) No Owl
2
Coefficients
0.113
0.4794
0.6833
1.0262
2.5
R2
0.0197
0.258
0.619
0.771
3
How and when did Chameleons reach the
Seychelles Islands?