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Review for Midterm Zoo511 - 2011
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Plan for today Go over Hypotheses/Questions Quick review of key concepts from each lecture via powerpoint slides – These are central ideas to most of the lectures, but there will be questions from slides that are not included today, so don’t just study based on today’s review! – These are simply slides from previous lectures, so no new material Question/Answer – You’ll get to review more material if you actually ask questions Hypotheses/Questions: Graded and emailed back to you with comments on the documents (note about reach length data) Midterm right after spring break – be ready! – Test format Start working on your rough drafts! – 1 st draft due in class Week 10 (March 29 or 30) Announcements
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Week 1 - Anatomy
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Maxilla Premaxilla Dentary
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Heterocercal Tip of vertebral column turns upward Epicercal: dorsal lobe larger (sturgeon) Hypocercal: ventral lobe longer (flying fish) Protocercal Extends around vertebral column Embryonic fish; hagfish Homocercal Vertebral column stops short of caudal fin, which is supported by bony rays Symmetrical Derived fishes Diphycercal 3 lobed; lungfish and coelacanth Vertebral column extends to end of caudal fin, dividing into symmetrical parts
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Spines Rigid Never segmented Often for defense Rays Flexible Often branched Mainly for support Fisheries ecologists use both spines & rays for identification and aging!
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Basic Mouth Types Superior Terminal Sub-Terminal Inferior
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Scale types Ganoid Placoid Cycloid Ctenoid
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Swim bladder Ovary Heart Liver Stomach Intestine Fat deposits
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Week 2 – Evolution and Functional Morphology & Fish ID’s
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Jaws Osteichthyes Gnathostomata Bony fish ActinopterygiiSarcopterygiiChondrichthyesAgnatha Fish Evolution: Cladogram
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Major Trends in Fish Evolution Changes in cranium and jaw structure – Branchiostegal rays – Pre-maxilla separation Changes in movement – Loss of external armor – Fins – Air bladders
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Body Types
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Jaw Shapes
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Practice
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Week 3 – Population Dynamics
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Nutrients (P and N) Large zooplankton Invertebrate Planktivore Vertebrate Planktivore
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N t+1 = N t + B – D + I – E B = births D = deaths I = immigration E = emigration How do populations change? Deaths Population Births Emigration Immigration Stocking Angling
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Rate of population increase Density independent Density dependent per capita annual increase N
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Logistic population growth K= carrying capacity r 0 = maximum rate of increase dN/dt=r 0 N(1-N/K ) per capita annual increase N K r0r0
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What determines recruitment? spawning stock biomass (SSB) Ricker Beverton-Holt Density-independent From: Wootton (1998). Ecology of teleost fishes. Recruitment
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Catch per unit effort (CPUE) Very coarse and very common index of abundance Effort= 4 nets for 12 hours each= 48 net hours Catch= 4 fish CPUE=4/48=0.083 Effort= 4 nets for 12 hours each= 48 net hours Catch=8 fish CPUE=8/48=0.167 We conclude population 2 is 2X larger than population 1 1 2
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Population abundance Density estimates (#/area) – Eggs estimated with quadrats – Pelagic larvae sampled with modified plankton nets – Juvenile and adult fish with nets, traps, hook and line, or electrofishing Density is then used as index of abundance, or multiplied by habitat area to get abundance estimate
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Mark recapture M=5 C=4 R=2 N=population size=????
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Week 4 – Age and Growth
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3 ways to estimate growth in natural populations Length Frequency Analysis Recaptures of individually marked fish Back calculation from calcified structures # Caught
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Age this fish:
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Age this fish
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Frasier-Lee L t = c + (L T –c)(S t /S T )
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Problems with back calculation Lee's Phenomenon AgeYr.Class123456 1198890 2198990115 3199080112139 4199175108133150 519926696129147160 619935992126147156166 LENGTH AT AGE
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Von Bertalanffy Growth Equation L t = L ∞ - (L ∞ - L 0 ) exp (-kt) – L t = length at time 't’ – L ∞ = length at infinity – L 0 = length at time zero (birth) – K = constant ( shape of growth line)
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L t = L ∞ - (L ∞ - L 0 ) exp (-kt) Linf =523.4 Lzero =57.54 k =0.081 Linf =500.6 Lzero =28.34 k =0.080 AL WS
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Week 5 – Badger Mill Creek
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Week 6 – Data and writing
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Order of a scientific paper (see handout!) 1.Title 2.Abstract 3.Introduction – set up your study 4.Methods – study site, data analyses 5.Results –analyses, reference tables and figures here 6.Discussion – interpret results 7.Literature Cited 8.Tables and figures
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Note on results Make ecology the subject of your sentences, not statistics. Statistics help you tell your story, they are not your story in themselves. WRONG: Linear regression showed that there was a significant positive relationship with a p-value of 0.04 and an R 2 of 0.81 between brown trout abundance and flow velocity. RIGHT: Brown trout abundance increased with increasing flow velocity (R 2 =0.81, p=0.04).
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Peer Review Criticism is important…”constructive criticism” is best! Two types: Internal and External. Point of internal review is to make external review go well Reviews need to be taken seriously
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Statistical Tests Hypothesis Testing: In statistics, we are always testing a Null Hypothesis (H o ) against an alternate hypothesis (H a ). p-value: The probability of observing our data or more extreme data assuming the null hypothesis is correct Statistical Significance: We reject the null hypothesis if the p-value is below a set value (α), usually 0.05.
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Tests the statistical significance of the difference between means from two independent samples Student’s T-Test Null hypothesis: No difference between means.
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Analysis of Variance (ANOVA) Tests the statistical significance of the difference between means from two or more independent groups Riffle Pool Run Mottled Sculpin/m 2 Null hypothesis: No difference between means.
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Simple Linear Regression Analyzes relationship between two continuous variables: predictor and response Null hypothesis: there is no relationship (slope=0)
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P-value: probability of observing your data (or more extreme data) if no relationship existed. Indicates the strength of the relationship, you can think of this as a measure of predictability R-Squared indicates how much variance in the response variable is explained by the explanatory variable. If this is low, other variables likely play a role. If this is high, it DOES NOT INDICATE A SIGNIFICANT RELATIONSHIP!
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Residual Plots Can Help Test Assumptions 0 “Normal” Scatter 0 Fan Shape: Unequal Variance 0 Curve (linearity)
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Week 7 – Foraging and Diets
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Holling’s Disc Equation C.S. “Buzz” Holling Holling, C. S. 1959. The components of predation as revealed by a study of small mammal predation of the European pine sawfly. Canadian Entomologist 91:293–320. Rate of Energy Gained = (λe – s)/(1 +λh) λ = rate of encounter with diet item e = energy gained per encounter s = cost of search per unit time h = average handling time Search Encounter Pursuit Capture Handling
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Predation rates ↑ with ↑ prey densities happens due to 2 effects: 1.Functional response by predator -Type 1 -Type 2 -Type 3 2.Numerical response by predator -Reproduction -Aggregation Holling’s Observations
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Enumerating the Diet The “Big 3” 1. Frequency of occurrence 2. % composition by number 3. % composition by weight Diet Indices
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