Download Introduction to Ecology and Evolutionary Biology

Introduction-to/Review-of Ecology
I.
Population Ecology
A. Human population
B. Simple population models
II.
Community Ecology
A. Community parameters
B. Interactions between
populations
III. Ecosystems Ecology
IV. Conservation Biology
ECOLOGY: the study of the interactions of organisms
with one another and with the physical and chemical environment.
Ecology is as easy as:
L(s, t )
L(s, t )
  L L(s, t )  m( x)
  (s) L(s, t ) P(t )  D(s) L(s, t )
t
s
Population: a group of the same
species living in a specific habitat
SIZE: number of
individuals
http://www.youtube.com/watch?v=4BbkQiQyaYc&feature=PlayList&p=A756CBD99E1CF7A3&index=0&playnext=1
Tanton, J.H. 1995. End of the Migration
Epoch. Social Contract 4:1-28.
http://www.ibiblio.org/lunarbin/worldpop
Ecology is...
•
The scientific study of interactions
among biotic and abiotic factors
that determine the distribution and
abundance of organisms
DENSITY: number of individuals per unit of area or volume
Source: Wikipedia
DISTRIBUTION: general pattern in which the population
members are dispersed through its habitat
Source: Science
Population Models
1.
2.
3.
4.
5.
6.
Create differential equation
for population growth rate.
State assumptions of the
model.
Solve for equilibrium.
Determine if equilibria are
stable.
Integrate equation to
provide predictions for
population size.
Relax assumptions.
ASSUMPTIONS
ASSUMPTIONS
1.
2.
No immigration or emigration.
Constant b and d (model is
deterministic).
ASSUMPTIONS
1.
2.
3.
4.
5.
No immigration or emigration.
Constant b and d (model is
deterministic).
No genetic structure.
No age or size structure.
Continuous growth without time
lags.
Lutz, W., Sanderson, W.,
and S. Scherb. 2001. The
end of world population
growth. Nature 412, 543545.
ALEE EFFECT
Carrying capacity
Verhulst 1838
ASSUMPTIONS
1.
2.
3.
4.
5.
No immigration or emigration.
Constant r (model is
deterministic).
No genetic structure.
No age or size structure.
Continuous growth without time
lags.
ASSUMPTIONS
6. Constant carrying capacity.
7. Linear density dependence.
Figure 9.20 Faster than
Exponential (Part 1)
Figure 9.20 Faster than
Exponential
AGE STRUCTURE: relative proportions of
individuals of each age--especially with
respect to reproductive years.
Introduction-to/Review-of Ecology & Evo
I.
II.
Population Ecology
Community Ecology
A. Community parameters
B. Interactions between populations
III. Ecosystems Ecoloy
IV. Conservation Biology
V. An extremely brief introduction to
evolution
NEUTRALISM
NEUTRALISM
MUTUALISM
Batesian bodies
Extrafloral nectary
Swollen thorns
Acacia cornigera
COMMENSALISM
epiphyte
AMENSALISM
Juglans sp.
lianas
COMPETITION
HERBIVORY
Seed predators
Fruit Borers
Parasites
Social Parasites
Parasitoids
APOSEMATIC
COLORATION
Community: an association of interacting populations of
different species living in a particular habitat.
Endophytic Invertebrate Community associated with P.
cenocladum
Arthropods
Nematodes
Annelids
Crustaceans
•• 77 shrubs housed 84,147 organisms, > 50 spp. ••
Community structure: the composite of
important parameters that give a habitat its
ecological distinction, such as: diversity,
number of trophic levels, dominant
interactions, ability to persist
Trophic levels: levels of organization determined by what the
members eat or produce
ENEMIES
A
G
C
D
HERBIVORES
B
H
Troubles and
enhancements….
Omnivory
IGP
Nonlinear trophic
structure
Functional trophic
levels
F
PLANT
CHEMISTRY
PLANT BIOMASS
I
J
E
RESOURCES
Mean number of families and morphospecies
Species richness: total number of species in
a community.
50
40
Families
Morphospecies
30
20
10
0
Temperatg
Tropical
Latitude
Continental shelf bivalves
Stehli et al. (Geol. Soc. Am. Bull. 78:455)
Insects in Texan vs. Costa
Rican deciduous forests
Diversity
Relative abundance: the number of
individuals of each species
Diversity: the
species richness,
abundance and
dispersion in a
given region or
system
USDA Photo by:
Anson Eaglin
Conservation Biology: a field that utilizes population biology
and ecological theory (or hypotheses) to guide
management of populations, communities, ecosystems, or the
biosphere.
Evolution
1.
2.
3.
4.
Origin of species
Microevolution
Macroevolution
Evolutionary
Ecology
‘Nothing in biology makes
sense except in the light
of evolution’
Dobzhansky, 1973
1. Species were not created in their present forms;
they have evolved from ancestral species.
2. One proposed mechanism is NATURAL SELECTION.
http://www.nature.com/nature/newspdf/evolutiongems.pdf
http://www.wired.com/wiredscience/2008/12/evolutionexampl
FACT 1: All species have such
great potential fertility that
their population size would
increase exponentially if all
individuals that are born
would reproduce successfully.
FACT 2: Most populations are
normally stable in size.
FACT 3: Natural resources are limited.
INFERENCE 1: Production of more individuals
than the environment can support leads to a
struggle for existence; only a fraction of
offspring survive.
FACT 4: Individuals of a population vary
extensively in their characteristics.
FACT 5: Much of this variation is heritable.
INFERENCE 2: Survival in the struggle for
existence is not random, but depends in
part on the heriditary constitution of the
surviving individuals.
INFERENCE 3: This unequal ability of individuals
to survive and reproduce will lead to a
gradual change in a population, with
favorable characteristics accumulating over
the generations.
NATURAL SELECTION: An evolutionary
theory which postulates the survival
and reproduction of the best adapted
forms whose characteristics arise as
random variations
ADAPTATION: adjustment to environmental
conditions through the long term
process of natural selection acting on
the genotype.
POPULATION: A group of interbreeding
individuals belonging to a particular
species and sharing a common
geographic area.
MICROEVOLUTION – change in allele
frequency over time.
MACROEVOLUTION – changes over longer
periods of time, including speciation and
larger phylogenetic changes.
Mechanisms of Evolution
Concept 6.2: Natural selection, genetic drift, and
gene flow can cause allele frequencies in a
population to change over time.
Four key processes influence evolution:
• Mutation
• Natural selection
• Genetic drift
• Gene flow
To study history one must know in advance that one
is attempting something fundamentally
impossible, yet necessary and highly important.
To study history means submitting to chaos and
nevertheless retaining faith in order and
meaning. It is a very serious task, young man
[or woman], and possibly a tragic one.
Herman Hesse
Biogeography
Fossil record
Comparative anatomy
Comparative embryology
Molecular biology
Systematics
Definitions
Systematics: the scientific study of the kinds
and diversity of organisms and of any and all
relationships among them.
Taxonomy: the theoretical study of
classification (ordering of organisms into
groups) its bases, principles, procedures, and
rules.
Simpson, G.G. 1961. Principles of Animal
Taxonomy. Columbia University Press, New
York.
Definitions
homology: similarity of a feature in two or
more organisms due to common ancestry
pleisomorphy: primitive feature; = ancestral,
generalized
apomorphy: derived feature; = advanced,
specialized
parsimony: of competing hypotheses choice of
the simpler
Definitions
monophyletic: contains all and only the
descendents of a unique common ancestor
polyphyletic: contains descendents of more
than one ancestor
paraphyletic: contains some, but not all, of the
descendents of a single ancestor
sister groups: two monophyletic groups that
together form a monophyletic group
Adaptive radiation:
Evolutionary divergence of members of a single phyletic
line into a series of rather different niches or adaptive
zones (Mayr 1963).
•Lack of competitors facilitates adaptive radiation
•Predators may prevent radiation
•Occupation of a new adaptive zone is followed by
a radical increase in rates of evolution and speciation
and major types develop