bio final
Levels of ecology-
Individual
Populations: Individuals of a species, in the same place and time
Community: All the species in an area, at the same time
Ecosystem: Community + environment factors
Biosphere: The highest level of ecological organization, encompassing all living organisms and their environments on earth
Metapopulation - populations of the same species that are distributed over space
If not maintained, it may result in speciation
Species niche
Environment
On the smallest scale: microhabitat - the space in which an organism lives (like a niche)
On a larger scale: habitat
Important roles of species within their community
Ecosystem engineers: greatly altering the physical environment benefits other species (Beaver)
Keystone species: A species with an impact on its community larger than its biomass or abundance - in terms of impact on organismal relationships within the community (Sea stars)
Niche Partitioning
Similar species adapted to use different parts of the habitat or at different times that allow them to co-exist
Bird example: owl and ravens
Biomes
Aquatic Biomes:
- Defined by salinity
- Freshwater biome: 1% salt, est. 6% of described species, source of water
- Ponds and Lakes: standing water
- Streams and rivers: moving water
- Characterized by the physical environment
- Special adaptation for water
- 75% of earth's surface
Terrestrial Biomes:
- Defined by climate and dominant plants
- Characterized by vegetation type and climate
- Tropical Forest
- Warm year-round (equatorial)
- Vegetation determined by rainfall
- Rainforest: 200-400 cm/yr
- Dry forest: lowland areas with prolonged dry seasons
- Complex structure
- Layering
- Creates microhabitats - great diversity
- Savana
- Poorer soil and limited rainfall
- Rainfall: 30-50 cm/yr
- Grasses and scattered trees
- Large fast predators and fleet grazers
- Large and small herbivores - elephants and termites
- Fire may be an important abiotic factor
- Clears the way for new growth
- Some seeds depend on fire exposure to germinate
- Grasses and some gymnosperms are well adapted to fire
- Termites and ants in Savana
- Large mounds: very tough
- South Africa
- Major herbivores
- Deserts
- Low and unpredicted rainfall
- < 30 cm/yr
- Hot or cold
- Large fluctuations in temperature
- Plant and animal adaptations
- Plants store water, reduced leaves, slow growing
- Animals estivation, active at night (Spadefoot toads - only emerge when it rains to mate and lay eggs)
- Chaparral (Mediterranean)
- Cool mild winters (near the coast) with hot dry summers
- California and the Mediterranean region
- Evergreen shrubs dominate
- Fire maintained
- Plants adapted for quick regeneration
- Seeds may need fire exposure to germinate
- With first rian, annual grasses and wildflowers grow
- Temperate Grassland
- Prairie, similar to savannas
- Most endangered biome
- Rainfall: 25-75 cm/yr
- Deep and rich soil - converted to agriculture
- Dominated by grasses
- Adapted to reduce rain and grazing
- Trees limited to streams
- Fire and grazing of large herbivores prevent tree establishment
- Temperate Broadleaf Forest
- Rain: 75-150 cm/yr
- Sufficient rain to support trees
- Even occurrence throughout the year
- Seasonality - varies
- Cold winters - hot summers
- Deciduous trees: drop their leaves in preparation for winter (avoid freeing)
- Leaf litter accumulation: lack of intense activity throughout the year
- Hibernation
- Coniferous Forest
- Dominated by gymnosperms-cone-bearing trees
- Taiga: northern coniferous forest
- Largest terrestrial Biome
Stretching across northern parts of northern America, Europe, and Asia
It also occurs at high elevations- rocky mountains
- Snowy winters; short summers
- Accumulation of needles makes soil acidic
- Slow growth
- Adaptations: the conical shape of trees reduces snow stress
- Temperate rainforests
- Coniferous forests- dominated by gymnosperms
Spruce, fir
Often near coast
- Pacific Northwest in Alaska, Oregon, Washington
- Appalachian mountains in North Carolina, Tennessee, and Va
Rain is dropped here due to the mountains
Remnants from the last ice age
Tundra
- Colder and less moisture available- frozen much of the time
- Permafrost: frozen land for 2 or more years
- Climate change is melting permafrost
- Causing many changes and difficulties
- Plant Adaptations to Tundra
- Early flowering
- Low growing
- Small, waxy leaves
- Hairs to hold in warmth
- Cup-shaped flowers to focus sun-light on the center of the flower-heating up
- Warm insect pollinators
- Polar Ice
- Arctic Regions, Antarctica
- Frigid and low precipitation year-round
- Most land is snowbound
- Plants: moss and lichens
- Animals: feed on these plants or from the surrounding sea
- Invertebrates, migrating birds, seals, penguins
General Adaptations
- Physiological Response
- Ability to adapt to changes in physiology
- Often a response to daily or seasonal climate change
- The longer-term: as a climate changes significantly in a region, organisms there may be able to adapt to these changes
- Anatomical adaptation
- Seasonal: color of coat changes for camouflage
- Behavioral responses
- Changes in activity based on seasonal changes
- Some desert ants shift to foraging at night based on the increase in daytime temperatures- the soil becomes too hot for the ants to walk on during the day
- Organisms have some ability to adjust to daily and seasonal changes in their environments
- Warmer weather to cooler weather
- Drier weather to warmer weather
- This may include migration
Names of Regions within Forest and Aquatic Systems
- Aquatic System
- Photic zone: light
- Aphotic zone: depth or murky-no light
- Benthic zone: at the bottom
- Phytoplankton: microscopic organisms
- Forest System
- Emergent trees- rising above the established canopy
- Canopy- tallest trees, first to access light
- Subcanopy- trees that can tolerate less light or are waiting for a chance to shoot up
- Understory and shrubs: tolerate less light
- Forest Floor: herbaceous plants, leaf litter
None in tropical rainforest
- Throughout
Lianas–vines
Epiphytes– orchids, moss
Biomes Adaptation to Fire
- Maintained by disturbance
- Frequent fire disrupts the expected succession to a climax community
- Examples: chaparral, savana, grassland
- Reduces the presence of trees
- Humans subject most ecosystems to disturbance-to which these other ecosystems cannot respond
- At the same time, humans prevent fire in these other systems
Causing a build-up of fire materials
Leading up to high levels of destructive fire
Difficult to contain, causing extensive damage
Human Impact on the Environment
Water
- Run-off from agricultural and other lands adds pollutants to soil and waterways
- Dams
- Increased erosion-loss of trees and grasses that hold soil
- Removal of dense vegetation-tropical rainforest conversion- and intense irrigation
Loss of moisture in the air
Increase evaporation- decrease groundwater
Land
- Conversion of land for human purposes
- Change from one land use to another
- Access-roadways-to these lands
- Impact of Construction Processes
- Fragmentation of land- creating smaller, often disconnected lands which are difficult for many species
- Forests
- Freshwater
- Forest Clearing
- About ¾ of the earth is altered due to human use
- Most for agricultural
- Due to unsustainable practices is worn out
- Urban development
- Run-off and other pollution
- Overuse of water resources
- Depletion of underground aquifers to grow grass in deserts and arid lands
- Too many people with increasing water demands
Species Interactions
All the living organisms living in the same area at the same time
Interactions among the species/populations
May be-
positive / helpful+
negative/harmful -
Neutral 0
- Interactions may help define the niche ( realized niche) of a species/ population
Their role in the ecosystem
- Interspecific Interactions
- Between different species in the same community
Competition
Mutualism
Symbiosis
Commensalism
Predation
Exploitation
Parasites
Trophic Groups
A simple consideration of trophic roles
Linear
Food Chain
- Trophic refers to feeding
- Trophic structure- how a community is organized
Levels-
- Producers- autotrophs, self-feeders, base of the food chain
- Primary consumers- consumer the producers
- Secondary consumers
- Tertiary consumers next quaternary consumers
- Trophic Pyramid
- Takes into account energy and nutrients
The energy passes through the levels
One-way
Lose most energy at each level used by that organism
When one organism is consumed, only 1/10 of its energy is passed on to the next level
-energy lost as heat ( metabolism)
This loss limits how many levels there can be
Apex predators are at the end of the levels
- Nutrients pass through the levels
Cycle
Another organism can always consume the nutrition in an organism
Ultimately, by fungi and bacteria, the decomposer
- Food webs
- Made from individual food chains
- Describes all the trophic terms
Herbivore (primary)
Omnivore (secondary )
Carnivore (secondary tertiary)
Detritivore (decomposers )
Food Pyramid
An organization of general trophic groups to understand the movement of energy in nutrients through organisms
Biomagnification
- A consequence of how trophic relationships work
- Toxins are magnified as they travel up a food chain
Because each higher level has to consume more than lower levels for energy
Accumulate in tissues
Higher level = higher toxins
That accumulation can be so high it can kill
Example- Polychlorinated Biphenyls (PCBs)
Species Diversity
Several measures of species or diversity
Species richness: a count of species in a community or area
Species abundance: how many of each species in a community
Species evenness: Combination
- Considered the best measure
Communities with
High species richness and even distribution are usually more healthy and resilient to change -including severe weather
Succession
The first establishment of life in an area
After a volcano eruption or other, even that lacks soil
As organisms come in they affect the abiotic and biotic factors of other organisms which organisms respond to
Life history traits and species interactions
- Stages to a climax community
- Colonizers: first organisms( pioneer species)
Make soil
Bacterial moss lichens
Small pores, easily dispersed
- Primary succession for different biomes
- Hardwood forest
- Desert and pond to forest
- Secondary succession
- Ecosystem can also respond to devastating changes
Fire or severe storm
Rarely destroys everything
Seed spores, plant roots in the soil
Burrowing animals
Immigration
Result of severe disturbance
Migration into area
- Wind dispersal: insects and spiders, birds (bird droppings dispersing seeds)