Module 8 Flashcards
Symbiosis
Sym = with biosis = to live
3 symbiotic relationships
- Commensalism
- Mutualism
- Parasitism
Commensalism
One benefits, other unaffected
Mutualism
Both benefit
Parasitism
One benefits one harmed
Commensalism example
- cattle egrets eat stirred up insects
- titan triggerfish moves large rocks for smaller fish
Mutualism examples
- clown fish and anemone: fish food scraps, anemone protected from predators
- barracuda and Spanish hogfish: mouth debris
- African croc and Egyptian plover: bird cleans teeth
- Flowering plants and birds/bees: pollen reward
Defensive mutualism
Ex. Acacia (defence) ants (reward): protection for food source
- Nectaries: sugar source for adults
- Beltian bodies: lipids, sugars, proteins for larval ants
2 kinds of mutualism
- Obligate mutualism
2. Facultative mutualism
Obligate mutualism
Highly dependent (cannot survive without eachother) Ex. Termites and flagellated protists in digestive system to digest cellulose
Facultative mutualism
Benefit but not totally dependent
Ex. Bees and plants (other species can)
Parasitism
*don’t generally kill host
Ex. Ticks: wounds, infection, hair loss,anemia
Ex. Birds and snails (hosts) flatworms (endoparasite) affect optic nerve
2 types parasitism
- Obligate parasitism
2. Facultative parasitism
Obligate parasitism
Parasite needs host to compete life cycle
Ex. Flatworm
Facultative parasitism
Does not rely on host
Ex. Naegleria fowleri: bacteria eating microorganism (shapeshifting amoeboflagellate)
Competition
- Contest for resources
- both harmed, cost to compete
- **driving force evolution and natural selection
Predation
One benefits, one harmed
Herbivory
One benefits one harmed
Non-symbiotic relationships
- Competition
- Predation
- Herbivory
Intraspecific competition
Same species
Interspecific competition
Different species
Ecological niche
Resources and environmental conditions that an organism require over its lifetime
Fundamental niche
Range of conditions and resources it COULD tolerate and use
Realized niche
- Range of conditions and resources it ACTUALLY needs in nature
- (smaller than fundamental niche)
Lotka and Volterra
-no 2 species w similar requirements can coexist in same niche without competition driving one to local extinction
Competitive exclusion principle
(Gause’s principle)
Two species competing for limited resources cannot coexist in the same place at the same time
Example competitive exclusion
Barnacles
- BALANUS only lower intertidal area
- CHTHAMALUS upper intertidal area
2 outcomes of Gause’s competitive exclusion principle
- One species drives the other to local extinction
2. Natural selection reduces the competition between the species
Robert MacArthur warbler study
- 5 species
- each feed on different parts of spruce tree
- evolution: use different parts
- subdivided niche
- avoid direct competition
- RESOURCE PARTITIONING
2 kinds interspecific competition
- Competitive exclusion
2. Resource partitioning
Competitive exclusion
Elimination of one species from habitat by other species with identical resource needs
Resource partitioning
Process permits 2 or more species to coexist by partitioning resources
(Differentiate ecological niches)
Predator adaptations
- sense (vision, smell, hear)
- hunting (stalking, sit-and-wait, group hunting)
- morphological (teeth, claws, jaws, strength, tongue)
Prey adaptation
- camouflage
- senses (vision, smell, hearing)
- behavioural
- defensive weapons
- morphological (spines, thorns)
- chemicals (chemical warfare)
- speed
Coevolution
When evolutionary changes in one species drive evolutionary changes in another species
Convolution example
- orange bellied newt (Taricha granulosa): tetradoxin, Na+ blocker, toxic
- garter snake (Thamnophis sirtalis) resistant to newt toxin, loss of speed movement = vulnerable
Community
Population of more than one species that live in the same place at the same time
Population
A single species, influenced by species interactions w other species and physical/chemical components
2 components of species diversity
- Species richness
2. Relative abundance
Species richness
Total # species
Relative abundance
How common/rare a species is relative to other species in the community
Universal feature of communities
Larger the area the more species will be found until total # species is reached
Species area relationship
More area usually means more species
Equilibrium model of island biogeography
MacArthur and Wilson 1967
-# species on an island tends toward equilibrium # determined by balance between immigration and extinction
Immigration curve
As colonists gill the island, rate of arrival of new species drops ()
Extinction curve
As colonists fill the island, rate species disappear increases (/) because interspecific competition increases
Species equilibrium
Where immigration and extinction curves cross
2 factors affect species equilibrium
- Distance
2. Area
Distance effect
Greater distance rod island decrease # species
Area effect
Larger island = higher equilibrium
Species diversity
- location related to mainland
- islands have fewer species than mainland
- islands higher extinction rate
- size influences diversity
“Islands”
- oceanic islands
- isolated forests
- lakes
Disturbance example
Eruption Mount St. Helens 1980
- erupted may 18th 1980
- killed 57 people
- created barren wasteland
Disturbance and recovery
-diversity changes overtime
Primary succession
Succession on newly espoused site that lacks soil and vegetation (ex. Volcanic islands)
Secondary succession
Succession on site that has already supported life but has undergone disturbance (ex. Fire, tornado, hurricane, flood)
Early stages more rapid
Lichens
- Often among first colonizers
- composite organism: fungus, green algae, Cyanobacteria)
- nutrients from rain and rocks
- mild acids erode rocks, develop soil for moss
Order primary succession
Pioneer species: -bare rock -lichens -small annual plants/lichens -grasses and perennials Intermediate species: -grasses, shrubs, shade-intolerant trees (pines) Climax community: -shade tolerant trees (oak, hickory)
Order secondary succession
Pioneer species: -annual plants -grasses and perennials Intermediate species: -grasses, shrubs, pines, young oak and hickory Climax community: -mature oak and hickory forest
Ecosystem
Biotic and abiotic communities of an environment
Ecosystem ecology
- Study movement of energy and materials through organisms and communities
- energy moves one direction: producers to consumers, autotrophs to heterotrophs
Food chains
Simple and linear
Food webs
Complex and interconnected chains
Primary producer
- base
- autotroph
- plants, protists, photosynthetic prokaryotes
Primary consumer
Herbivore
Ex. Caterpillar
Secondary consumer
Carnivore
Ex. Lizzard
Tertiary consumer
Secondary carnivore
Ex. Snake
Ecosystem primary production
Amount of light energy converted to chemical energy (organic compounds) by autotrophs
Secondary production
Amount of chemical energy in consumers food converted to new biomass during given time period
Efficiency energy transfer between trophic levels
- 10%
- loss energy represented by pyramid of net production
Detritus (debris)
Material and dead remains of animals and waste products
Detritivores
- Organisms that get energy from detritus (decomposers/ saprotrophs)
- carry 80-90% consumption of plant matter
- 2nd trophic level
Higher trophic level =
Lower energy available
Most food energy lost as heat
Pyramids of biomass
Based on biomass at each trophic level
May be inverted depending on ecosystem
Pyramid of numbers
Based on # organisms at each trophic level in a given ecosystem
(Upright or inverted depending on ecosystem)
Pyramid of energy
Normally upright
Removing top carnivores
Reciprocal changes in population of predators and prey in food chain
(Often dramatic ecosystem change)
Trophic cascade
-removal top carnivores from ecosystem
Conservation predators = maintenance structure
3 type ecosystem organisms
- Dominant species
- Keystone species
- Invasive species
Dominant species
- highly abundant
- control occurrence/distribution other species
Keystone species
- pivotal in community dynamics
- strong STRUCTURAL control
- engineers (physical changes ex. Beaver dams)
- facilitators (positive effect survival reproduction other species)
Invasive species
- Effect stability and structure
- better competitors than native species
- pioneer species, few native species
- prey on organisms that lack anti-predatory defence
- REDUCTION species diversity
Example keystone species
- starfish (taken over by zebra mussels)
- sea otter (eat sea urchins which feed on kelp)
- beavers
Invasive species example
- brown tree snake
- zebra mussels
Why are invasive species successful?
- Better competitors
- Pioneers species, few predators
- Prey on defenceless organisms
- No parasites
Extinction
- opposite speciation
- species no longer in existence
Functional extinction
- Reduced # individuals left
- population no longer viable
- low chance reproduction
Extinction vortex
Downward spiral, cannot naturally recover, caused by inbreeding and genetic drift
Extinct
Species disappeared/ lost globally
Extirpated
Species disappeared/ lost locally (regional)
Endangered
Species facing imminent extirpation or extinction
Threatened
Species likely to become endangered if nothing is done to reverse factors
Special concern
Species that may become threatened or endangered due to biological characteristics and threats
Not at risk
Species not at risk of extinction under current circumstances
Canadian mammals
1/3 endangered, threatened, special concern
Example endangered species
Beluga whale
Example threatened species
swift fox
Average estimated extinction rate
1-10 species/ 5 years
Contemporary (current) extinction rate
Increases 1,000-10,000 times
Bird extinction rate
1-2 per 100 years
-106 since 1800, only should be 2-4
Charles Elton
Ecological pyramids to show relative amounts of parameters across trophic levels
3 Saskatchewan invasive species
- wild boar
- purple loosestrife
- Prussian carp
