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

Ecological hierarchy Population-level processes Individual interactions

The Ecological Hierarchy Biosphere Ecosystem Community Population Individual

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

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

POPULATION EFFECTS - prey population 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) Predation

Predation Example: Stationary Predator Anthopleura xanthogrammica

Mobile predators

Crypsis : Decorator crab flatfish

Thaumoctopus mimicus mimic octopus mb=0&aq=f# Instructor: here is a recommended link to use for class

Pseudoceros bifurcus (flatworm in Phillipines) has tetrodotoxin (blocks Na channel) Aposematic (warning coloration) Instructor: here is a recommended link to use for class

Escape Behavior Scallop Lima hians Spisula escaping starfish

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

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

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

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

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

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

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.

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

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

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

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

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

Modes of Population Change Exponential Growth Logistic growthRandom change

Small-scale Spatial Distribution of Individuals Random Uniform Aggregated…

Metapopulation Definition: A group of interconnected subpopulations Sources and Sinks Aggregations on larger scales….