3 Ecological and Evolutionary Principles. Notes for Marine Biology: Function, Biodiversity, Ecology by Jeffrey S. Levinton

Transcription

1 3 Ecological and Evolutionary Principles Notes for Marine Biology: Function, Biodiversity, Ecology by Jeffrey S. Levinton

2 Ecological hierarchy Population-level processes Individual interactions

3 The Ecological Hierarchy Biosphere Ecosystem Community Population Individual

4 Ecological Processes - Population Level Competition Predation Parasitism Disturbance Facilitation Larval dispersal (unique to ocean)

5 Interactions Between Individuals +- Territoriality +- Predation + - Parasitism ++ Mutualism + 0 Commensalism

6 Predation POPULATION EFFECTS - prey population reduction or even collapse, occasional predator-prey cycles Predation effects reduced when (a) Prey population has rapid recovery rate (b) Predators limited by other factors (e.g., octopus by den sites) (c) Escapes from predation: (1) escape behavior, (2) cryptic color, form, (3) chemical (warning coloration) or mechanical defense (fixed or inducible), (4) refuge habitat, (5) refuge time (nocturnal, feeding at time of low tide when predators are away)

7 Predation Example: Stationary Predator Anthopleura xanthogrammica

8 Mobile predators Drilling snail, Nucella lapillus Blue crab, Callinectes sapidus Oyster catcher Haematopus ostralegus

9 flatfish Crypsis: Decorator crab

10 sea snake flounder Thaumoctopus mimicus mimic octopus

11 Aposematic (warning coloration) Pseudoceros bifurcus (flatworm in Phillipines) has tetrodotoxin (blocks Na channel)

12 Escape Behavior Scallop Lima hians Spisula escaping starfish

13 Inducible defenses bryozoan spines - nudibranch. Why just a plastic response? +predator - predator Barnacle Chthamalus anisopoma

14 Optimal Predator Models Diet breadth - rule: food scarce, increase breadth Time spent in a patch - rule: greater the distance between patches, spend more time in a given patch Size selection - maximize energy intake, usually leads to selection for intermediate size

15 Energy reward of a mussel as function of size Shore crab Carcinus maenas feeding upon the mussel Mytilus edulis. Preference of crab for different mussel sizes Optimal Prey Size: Maximize intake - Function of time and prey size

16 Parasitism Parasites evolve to reduce damage to host Commonly involve complex life cycles with more than one host Parasites may invade specific tissues, such as reproductive tissue of the host

17 Complex life cycle found in a trematode parasite living in several marine animal hosts

18 Invasion of the parasitic rhizocephalan barnacle Sacculina into the body of a crab Planktonic larva of parasitic barnacle (attaches to 1st antenna of crab)

19 Mutualism: Cleaner wrasse removes ectoparasites from a number of species of fish that visit localized cleaning stations on a coral reef. Fish (b) is a mimic species that actually attacks fish that would normally be a client of the cleaner wrasse.

20 Commensalism Commensal crab and fish live in this burrow of Urechis caupo

21 Effects of Disease Destruction of important species, e.g., shellfish disease attacks Removal of ecologically important species (example: removal of key grazer) Interaction with other factors such as climate change

22 Construction of a Population dn/dt = f (N,M,R,I,E) N = population size M = mortality R = reproduction I = immigration E = emigration Model M is a function of physical environment, competition, predation, etc. R function of physical environment, resources (e.g., food)

23 Example of Population Model Barnacles: What parameters matter the most? dn/dt = f (N, I, M) I is larval settlement M a function of larval-adult interactions, overgrowth, predation Note R doesn't matter if planktonic larvae mainly go elsewhere

24 Mortality pattern expected for a species with a planktonic larva. Note higher mortality rate of larval stage.

25 Modes of Population Change Exponential Growth Logistic growth Random change

26 Small-scale Spatial Distribution of Individuals Random Uniform Aggregated