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Ecology (BIO 47)
Review for Exam 1
Introduction to Ecology
Definition of ecology
Ecology can be studied on different levels. List them.
What kinds of questions do ecologists working at these different levels ask?
What are some of the methods that ecologists use?
What is the difference between correlation and causation?
What are the parts of the scientific method?
Evolution for Ecology
Proximate vs Ultimate questions
Pink Bollworm example
Bollworms are pests on cotton
Pests can evolve resistance to chemical pesticides - become less effective
Pesticides are bad for environment
Transgenic cotton includes a gene from a bacterium that kills bollworms
Not so bad for the environment
Can bollworms evolve resistance? YES
Solution?
Balance the ratio of normal cotton to transgenic cotton. WHY?
Stickleback example
Armor plates provide protection from predators
Cost to plates: lower winter survival, slower growth
Predators hunt better in clear water
What do we expect to see in murky water, clear water?
Plant example (snowy campion)
Invasive weed in North America – no natural enemies
Allocation of resources
Mostly to growth when no enemies
More toward defense when there are enemies
Natural selection requires
Variation - Sticklebacks vary in the number of bony plates
Heredity – number of plates is genetic
Differential reproduction – where there are predators, sticklebacks do
better if they have plates.
Galapagos Finches
Variation in beak depth
Beak depth is genetic (heritable)
During a drought, birds with large beaks survive better leading to in increase
in average beak depth in the population.
Genetic terms
Phenotype vs genotype
Genes vs alleles
Evolutionary fitness (an individual’s genetic contribution to next generation)
Stickleback plating is controlled by a codominant gene (you can see the
heterozygote)
cc = completely plated
cl = partially plated
ll – low plated
Tradeoff between fast growth & survival vs. protection from predators.
Natural selection will favor different phenotypes with different
environmental pressures.
Over time, Natural selection leads to adaptation to the environment.
Genetic drift is another mechanism for changing frequency of alleles in the
population. – Cause of change is RANDOM & NO adaptation occurs.
Population Genetics and Natural Selection
Definition of Heredity
Who was Gregor Mendel?
Experiments with garden peas
Parental generation (true-breeding purple x true breeding white)
F1 generation all purple
F2 generation 3:1 purple:white
Dominant vs recessive
Phenotype vs genotype
Homozygous vs heterozygous
Be able to use a Punnett square to predict genotypes of offspring
Mendel’s laws
Law of Segregation
Law of Assortment
Continuous variation – due to multiple genes (polygenic)
Incomplete dominance & codominance give heterozygotes a different appearance
Who was Charles Darwin
What was the Beagle?
How did Malthus influence Darwin?
Define Natural Selection
Stabilizing selection
Directional selection
Disruptive selection
How does it compare to artificial selection?
Define and give an example of adaptive radiation
Give examples of evidence for evolution (fossils, anatomy, homologous structures)
Population genetics
Gene pool
Hardy Weinberg equilibrium
Name the 5 assumptions required for HW equilibrium
What is genetic drift?
Agent of evolution (results in a change in frequency of alleles)
Random
No adaptation occurs
Founder effect
Bottleneck effect
What is the biological species concept?
Isolating mechanisms (prezygotic, postzygotic)
Behavior Ecology
How does behavior influence how organisms interact with their environment?
(Behavioral ecology)
Finess – maximizing reproductive success
What behaviors lead to increased fitness?
Optimal Foraging models
Pikas’ foraging strategies
How far should it travel?
What happens if predators are present? (Wary behavior)
What kind of food should be chosen?
Handling time
Nutritional value
Profitability = Energy/handling time
Specialists vs generalists
Switch to generalist if S1>(E1h2/E2)-h2 (I will provide this formula if
it is on the exam – you should know what it is for and how to plug numbers
into it)
Territories allow animals to defend limited resources
How should animals interact when they encounter a rival?
Game Theory
Animals will maximize their fitness
Hawk vs Dove strategy
Bowerbirds – when should they guard & when to wreck another bird’s bower?
Evolutionarily Stable Strategies (ESS) – can not be invaded by an alternative
strategy
Sexual selection
Intersexual selection (mate choice – peacocks with fancy tails)
Intra sexual selection (males compete – larger, more impressive males)
Widowbird experiment – females prefer long tails
Life history characteristics
Monogomy, polygyny, polyandry, polygynandry
Bluegill experiments – parentals vs cuckolders
A male is more likely to provide parental care if he is sure he is the father
Cooperation
Altruistic behavior – helping someone at a cost to yourself
Vampire bats – reciprocity
Tit-for-tat strategy
Belding’s ground squirrels – alarm call behavior
Aerial predators – benefits caller
Terrestrial predators – kin selection
Hamilton’s rule
Natural selection will favor altruistic behaviors if rB-C >0
r= coefficient of relatedness
B=benefits
C=costs
Turkey partnerships – explain how helping benefits subordinate males.
Inclusive fitness = direct + indirect fitness
Eusocial systems – only specific individuals get to breed
Honeybees show haplodiploidy
Females are diploid (develop from fertilized eggs)
Males are haploid (develop from haploid eggs)
Sisters are more closely related (r=0.75)
Greater benefit for them to raise sister vs own offspring
Physiological Ecology
Physiology –study of how organisms work, metabolism
Species distribution patterns
Precipitation
Temperature
Be able to read a Whittaker diagram
Physiological tolerances – what a plant can tolerate
Transpiration +evaporation = evapotranspiration
Understand how water moves through a plant (roots up to leaves – transpiration
from leaf surface)
Be able to read a climate diagram
Define a niche
Leibig’s law of the minimum – what is it?
If optimal environment changes species can:
Migrate
Go extinct
Adapt
Adaptation vs acclimation
Individuals can acclimate (get used to) new condition
Populations adapt through natural selection (involves genetic change)
Give examples
Homeostasis (define)
What is surface area to volume ratio?
Which has a greater surface area to volume ratio an block-shaped toad, or a
long snake?
Understand components of heat balance and water balance
Metabolism – all chemical reactions going on in body
Photosynthesis & respiration – recognize equations
Understand the basic differences between C3, C4, and CAM photosynthesis (where
and when do light dependent and independent reactions occur – same cell, different
cells, day, night)
What is the benefit of CAM or C4 photosynthesis?
How does water potential affect plants?
What can a plant do to avoid cavitation?
Stomata – Benefits of opening/ closing?