Ecology:


| Ch. 51 - Animal Behaviour | | Ch. 52 - Ecology and the Biosphere | Ch. 53 - Population Ecology | Ch. 54 - Community Ecology | Ch. 55- Ecosystems

Ch. 51 - Animal Behaviour


Must know:
- kinesis/taxis
- animal communication
- altruism, inclusive fitness, kin selection

Behaviour:
- what an animal does, how it does it
- result of genetic and environmental factors
- natural selection

Ethology:
- study of animal behaviour

2 Levels of Analysis >> Proximate and Ultimate
Proximate: "how", heredity, genetic/environment, sensory motor mechanisms
Ultimate: "why" origin of behaviour, change over time, utility in reproductive success

Innate Behaviours:
- developmentally fixed, unlearned

Fixed Action Pattern:
- sequence of unlearned acts
- unchangeable
- carried to completion
- triggered by Sign Stimuli
- ex. fish attacks red object, attack is FAP, red object is sign stimulus

Kinesis:
- movement in response to a stimulus but in no particular direction

Taxis:
- an automatic movement toward or away from a stimulus

Migration:
- navigation by magnetic field, visual cues, etc.

Circadian Rhythms:
- occur on daily cycle

Signal:
- movement causing change in behaviour of another individual, basis for animal communication
Pheromes: chemical signals
Visual Signals
Auditory Signals

Learning:
- modification of behaviour based on experiences

Imprinting:
- learned and innate compnents
- limited to a sensitive period
- generally irreversible
- ex. baby geese imprinting on humans

Habituation:
- loss of responsiveness to stimuli that conveys little/no information
- simple learning

Cognitive Map:
- internal representation of spatial relationships among objects in surroundings

Associative Learning:
- ability of animal to associate one feature of environment with another
Classical Conditioning: learning to associate stimuli with reward/punishment
Operant Conditioning: learning to associate its behaviour with reward/punishment

Cognition:
- ability of nervous system to perceive, store, process, use info from sensory receptors

Foraging:
- eating, searching, recognizing, capturing food
- compromise between benefits of food and cost of obtaining

Mating systems:
Promiscuous: no strong pair bonds
Monogamous: one male/one female
Polygamous: one individual, several others

Agonistic Behaviors:
- ritualized contests that determine access to a resource

Altruism:
- animals behave to reduce individual fitness, but increase fitness of other individuals
- leads to reproductive success of relatives, Kin Selection

Inclusive Fitness:
- total effect individual has on proliferating genes
- own offspring, altruism that enables close relatives to produce


Ch. 52 - Ecology and the Biosphere


Must Know:
- abiotic factors in forming biomes
- freshwater and marine biomes
- major terrestrial biomes

Ecology:
- study of interactions between organisms and environment

Biotic = living
ex. behaviour

Abiotic = nonliving
ex. temperature, salinity, sunlight

Climate:
- long term weather patterns made up of temperature, precipitation, sunlight, wind
Macroclimate patterns: global, regional, local
Microclimates: small scale variations, ex. under a log

Biomes:
- major types of ecosystems
- occupy broad geographic regions

Aquatic biomes = 75% earth's surface


Terrestrial Biomes:

Savannas
savanna2.jpg
- grasses, some trees

Desert
external image namib_desert_pictures.jpg
- sparse rainfall, desert plants

Chaparral
external image 555_PS-Chamise-RS-chaparral.jpg
- dense, spiny, evergreen shrubs
- mild rainy winters, long dry summers

Temperate grassland
external image 800px-Grasslands-menggu.JPG
- seasonal drought
- no trees, rich soil, good for agriculture

Temperate broadleaf forest
external image 400px-OlympicRainforestHiker.jpg
- dense deciduous trees
- lots of rain

Coniferous forest
external image 93105-050-1A1A18DB.jpg
- conifers

Tundra
external image arctic.tundra.jpg
- permafrost, cold, little rain, no trees

Tropical forest
external image hua-image002.jpg
- vertical stratification
- warm, lots of rain



Ch. 53 - Population Ecology


Must Know:
- density, dispersion, demographics
- exponential and logistic growth models
- density dependent and density independent factors

Population:
- group of individuals of species in same general area
Population Ecology:
- how biotic/abiotic factors influence density, distribution, size, age structure

Density:
- number of individuals per unit area
- increases by births/immigration, decreases by deaths/emigration

Dispersion:
- pattern of spacing of individuals
Clumped: patches, usually around a resource
Uniform: usually to defend territories
Random: unpredictable, uncommon in nature

Demography:
- study of vital statistics of population, esp. birth/death rates

Survivorship Curves:
external image survivorship.gif

Life History:
- made of traits that affect an organism's reproduction and survival
- evolutionary outcomes
1. age of sexual maturation
2. how often reproduces (big bang event, repeated reproduction)
3. number of offspring per event

external image expgrowth.gif
Exponential Population Growth:
- ideal, unlimited conditions
- any species is capable of exp. growth if resources are abundant
- grows quickly, rate increases over time
r-selection: life history traits that maximize reproductive success

Logistic Population Growth:
- grows more slowly as it nears carrying capacity
- per capita rate of increase declines as carrying capacity reached
K-selection: life history traits sensitive to population density/carrying capacity
- operates in pops living close to carrying capacity
Carrying Capacity: maximum population size an environment can support at a certain time with no degradation of habitat

K vs. r: two ends of a continuum of life history strategies

Life History Traits:
r-strategist
K-strategist
- grow fast
- mature quickly
- smaller
- expanding population
- short life
- big bang reproductino
- large # of offspring
- ex. weed
- live long
- mature slowly
- bigger
- fairly constant population
- repetitive reproduction
- ex. cedar tree

Death rate rises and birth rate falls as population density rises = density dependent factors:
1. Competition for resources like food, space
2. Territoriality, available space may be limited
3. Disease, higher density allows easier transmission of disease
4. Predation, higher density means predators find prey more easily

Death rate doesn't change with increase in population density = density independent:
ex) natural disasters

Demographic transition:
- high birth/death rates to low birth/death rates

Ecological footprint:
- total land/water area needed for humans



Ch. 54 - Community Ecology


Must Know:
- fundamental niche/realized niche
- competitive exclusion
- symbiotic relationships
- keystone species
- primary/secondary succession

Community: group of populations ofdifferent species living close enough to interact

Interspecific competition: competition between different species
- when resources are in short supply, -/- interaction
1. Competitive Exclusion Principle: when two species vying for resource, one with reproductive advantage will eliminate other
2. Ecological Niche: total sum of biotic and abiotic resources species uses
- Fundamental Niche: niche potentially occupied by species
- Realized Niche: portion of the fundamental niche species actually occupies
ex. finches competing for same resources like food

Intraspecific competition: competition within a species
ex. two male wolves fighting over territory

Predation:
- +/- interaction
- predator eats prey

Defenses:
1. Cryptic Coloration: camoflaged by colouring
2. Aposematic or Warning Coloration: poisonous animal brightly colored as a warning
3. Batesian Mimicry: harmless species mimics coloration of harmful/unpalatable species
4. Mullerian Mimicry: two bad tasting species resemble each other, predators learn to avoid both
5. Herbivory: +/- interaction, herbivore eats plant or algae, plant's protection includes chemical toxins, spines,thorns

Symbiosis: individuals of two/more species live in direct contact
1. Parasitism: +/-, parasite gets nourishment from host, negative effect on host
ex. tube worm, mushroom living on tree
2. Mutualism: +/+, both species benefit
ex. pollinators and flowering plants
3. Commensalism: benefits one, doesn't affect other
ex. fern growing in shade of tree

Species Diversity:
- measures number of different species in community (species richness)
- relative abundance of each
- even species abundance = more diverse than if only a few are abundant and others are rare

external image tropic.jpg
Trophic Structure:
- feeding relationships
- Trophic Levels: links in trophic structure

Food chain: sun>plants>herbivores>carnivores>decomposers
Food web: 2 or more food chains linked together

Dominant Species:
- highest biomass (sum weight of all members in population)

Keystone Species:
- important ecological niche
- control on community structure

Disturbance:
- ex. storm, fire, flood
- removes organisms, changes resources
- not necessarily bad
- Intermediate Disturbance Hypothesis: moderate levels of disturbance foster greater species diversity than low/high

Ecological Succession: transition of species composition over time
external image 12343713.jpg
- Primary succession: plants/animals gradually invade, soil created
external image Succession.gif
- Secondary succession: existing community was cleared by disturbance but soil intact
Biogeographic Factors affecting Community Diversity:
1. Latitude: more diverse in tropics, less so toward poles
2. Area: larger geographic area = more species
Island biogeography: isolation and limited size = natural laboratory
- immigration and extinction influenced by size and distance from mainland
- greater size = higher immigration, lower extinction
- higher distance from mainland = immigration falls, extinction increases



Ch. 55- Ecosystems


Must Know:
- how energy flows through ecosystems; food chains, webs
- gross primary productivity/net primary productivity
- carbon and nitrogen cycles

Ecosystem:
- sum of all organisms and abiotic factors in the community
- involves energy flow and chemical cycling

- flow of energy traced through trophic levels, food chains/webs
- energy cannot be recyced, must be constantly supplied (sun)

Primary Producers:
- autotrophs (self feeders)
- support all other organisms

Heterotrophs:
- can't make own food
- consumers

external image 53-10-FoodChains-L.jpg
- Herbivores eat producers (primary consumers)
- Carnivores eat herbivores (secondary consumers)
- Carnivores eat carnivores (tertiary consumers)

Detrivores/Decomposers
- get energy from nonliving organic material
- detritus, dead organisms, feces, dead leaves, wood
- convert organic materials to inorganic compounds used by producers

- a species may feed at more than one trophic level
- may change through different stages in life cycle

Primary Production:
- amount of light energy converted to chemical energy by autotrophs
- amount photosynthetic production sets energy budget for whole ecosystem

Gross Primary Production (GPP):
- total primary production
- not all available to consumers
- some used to fuel producer's cellular respiration

Net Primary Production (NPP):
- gross primary production minus energy used for respiration (R)

NPP = GPP - R

- primary production in aquatic ecosystems affected by light availability (decreases with depth) and nutrient availability (usually nitrogen/phosphorus)
- a nutrient-rich lake that supports a vast array of algae is Eutrophic

Evapotranspiration:
- water transpired by plants, evaporated from landscape
- combines key controlling factors in terrestrial ecosystems

- only 10% of energy transferred up trophic levels
- loss of energy keeps food chains short

external image pyramids.png
- pyramids of energy never inverted
- pyramids of numbers and aquatic biomass pyramids may be inverted

Biogeochemical Cycles:
- biotic and abiotic components
- trace how nutrients flow

external image 54-17-CarbonCycle-L.gif
Carbon Cycle:
- balance between CO2 removed by photosynthesis, added by cellular respiration

external image nitrogenCycle.jpg
Nitrogen Cycle:
- nitrogen is common limiting factor for plant growth
- most nitrogen in form N2, unusable by plants
- Nitrogen Fixation by bacteria converts N2 into form usable by plants
- Nitrification converts NH4+ (ammonium) into NO3- (nitrate)
- nitrates and ammonium can be absorbed by plants
- Denitrification releases nitrogen into atmosphere

- other important nutrient cycles: water, phosphorus

Acid Precipitation:
- rain/snow with pH less than 5.6
- burning wood/fossil fuels releases sulfur/nitrogen oxides
- reacts with water to become sulfuric/nitric acid

Biological Magnification:
- toxins become more concentrated as trophic level increases

Greenhouse Effect:
- absorption of heat due to certain atmospheric gases
- CO2 and water vapor absorb infrared radiation

Ozone Layer:
- reduces UV radiation penetration
- chlorine containing compounds erode ozone layer