APES Review 4 Ecosystems
Ecosystem Structure
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Population Dispersal
all biotic and abiotic factors in an
area that functions together
-clumped
organisms
-linear
species
populations
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communities
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ecosystems
-random
-uniform
biosphere
Ecosystem Characteristics
*niche structure- # of niches, how they
resemble each other or differ, includes
species interactions
*physical appearance-relative
size,stratification, distribution of
populations and species
*species diversity-number of different
species
*species abundance-# of individuals of
each species
Specialist Species
Generalist Species
Symbiosis
-live in narrow niches
-more prone to extinction than
generalist
-in stable environmental conditions,
specialist have an advantage b/c few
competitors as each species occupies its
own niche.
- Ex. Giant Panda
-live in broad niches
-able to withstand a wide range of
environmental conditions
-close and often long-term interactions
between different biological species
-ectosymbiosis: organism lives ON
another (Ex. Mistletoe, tick)
-endosymbiosis: organism lives IN
another (Ex. Bacteria in human,
zooxanthelles in coral)
Amensalism
Commensalism
-when rapid habitat change, generalists
fare better b/c they are more adaptable
-Ex. Cockroaches, mice, humans
Competition
-driving force of evolution
-interspecific
-intraspecific
Types (examples) of Competition
Competitive Exclusion Principle
-Interference
-Apparent
- two species competing for the same
resources cannot coexist if the ecological
factors stay the same.
1. 1 species will become extinct
2. 1 species will be forced into evolutionary
or behavioral shift toward a different
ecological niche.
Ex. Two species of paramecium
Mutualism
Parasitism
-Exploitation
-Ecto-Endo-Epi-Biotrophic
-Nectotrophs
-Social parasites-
Predation
Saprotropism
Keystone Species
-Species whose presence contributes to
Aquatic Biomes
Terrestrial Biomes
Major Biome – Grassland
Major Biome – Savanna
Major Biome – Taiga (Boreal)
-Between 45 and 60
Major Biome – Temperate
Deciduous Forests
Major Biome – Temperate
Scrub(Chaparral)
Major Biome – Tropical Rain Forest
Major Biome – Tundra
Aquatic Organisms & Diversity
Desert Animals & Diversity
-small, small surface areas to prevent
Desert Plants & Diversity
Grassland Animals & Diversity
-spread apart due to limiting factors
-succulents store water
-small surface area, aligned vertically to
decrease sun exposure
-open stomata at night
-waxy leaves
-deep roots to reach ground water
-shallow roots to absorb limited rainfall
-spines discourage herbivores
-secrete toxins to reduce interspecific
competition
-store biomass in seeds
-wildflowers have short life spans
-grazers and browsers eat vegetation at
different heights
-smaller animals migrate to find water
-some become dormant
-some survive on seeds during dry
season
-some live in burrows to hide
-fur color acts as comouflage
a diversity of life and whose extinction
would lead to extinction of other forms
of life.
-Large and disproportionate impact on
how ecosystems function
Ex. Grizzly (nutrients from ocean to
forest, Sea Star (keeps pop. Of urchins,
mussels, etc. in check), Prairie Dogs…
Major Biome – Desert
-Between 15° and 25° N & S latitudes
-20% of land surface
-< 20 in. (50cm) rainfall/year
- descending air, so not as much rain.
-soil=sand, nutrient rich but lack of
organic matter and little humus.
water loss
-spend time in burrows
-often nocturnal
-aestivation (reduced metabolic act.)
-able to metabolize dry seeds
-Kangaroo rats secrete concentrated
urine
-Insects and reptiles have thick outer
scales
Grassland Plants & Diversity
Forest Animals & Diversity
Forest Plants & Diversity
-grasses grow from bottom so they
grow again after being nibbled by grazers
-grasses are drought resistant
-deciduous trees and shrubs shed
leaves during dry season to conserve
water
-some hibernate to conserve energy
when food is scarce.
-some live in canopies (abundant food
and protection from predators)
-Birds may migrate when food
resources become scarce
-nuts and seeds stored by rodents and
birds for use during winter months.
-epiphytes(orchids and bromeliads) live in
branches to catch falling debri or rainwater.
-large leaves to capture limited light
-tree roots are shallow to capture limited
nutrients
-buttresses aid in support
-flowers have elaborate devices to attract
pollinators (wind is limited)
-temperate deciduous trees lose leaves to
conserve water and energy
-shift metabolic pathways due to
temperature
-coniferous trees have small, waxy-coated
needles and continually replace needles.
-decomposed needles create acidic soil to
reduce competitors.
Temperate Scrub (Chapparal)
Animals
-rodents are common and store seeds
Temperate Scrub (Chapparal) Plants
Tundra Animals
in burrows
-nocturnal, burrow underground to
escape heat in the day, feed at night.
Will save water and energy and stay safe
during fires.
-some mice and lizards secrete a
semisolid urine in order to reduce water
loss
-small waxy-coated leaves help to
reduce transpiration
-some plants release toxins that enter
the soil
-vegetation becomes dormant during
dry season
-leaves do NOT fall during dry season to
reduce stress of replacement
-thorns are adaptations for protection
-plants are adapted to fires due to high
oil content
-fires reduce competition
-have extra layers of fat; chemicals in
blood to keep it from freezing
-compact bodies to conserve heat
-thick skin and/or fur
-waterproof feathers and/or downy
insulating feathers
-most migrate in winter to avoid limited
resources during winter
-lemmings live underground during
winter
Tundra Plants
Edge Effect
Photosynthesis
Carbon flux in Ecosystem Cycle
Primary Producers
-Polar grasses are adapted to low levels
of sunlight, low amounts of free water,
high winds, and low temperatures
-Grasses primarily grow in summer
months
-Leaves have waxy coatings to reduce
water loss
-Plants can survive as roots, stems,
bulbs, or tubers
-Lichens dehydrate during winter to
avoid frost damage
Respiration
-defense mechanisms
Desert Food Web
Oceanic Food Web
Coniferous forest Food Web
Deciduous forest Food Web
Tropical rain forest Food Web
Temperate rain forest Food Web
Tundra Food Web
Biomass Energy Pyramid
Aquatic Ecosystem Biomass Pyramid
(exception)
Biodiversity
Biodiversity Hotspot
Natural Selection
Types of Natural Selection
Speciation
-adaptive radiation
Convergent Evolution
Evolutionary Relay
Parallel Evolution
Gradualism and Punctuated
Equilibrium
Ecosystem Services
Valuation of E.S. 1
Valuation of E.S. 2
-Processes by which natural ecosystems
produce needed resources for humans
such as clean water, timber, habitat for
fisheries, and so on.
-Provisional
-Avoided Costs: society avoids costs
that may have incurred if service was not
available. Ex. Waste water treatment by
Wetlands as apposed to a Municipal
treatment Plant
-Replacement Costs: Service replaced
with some man-made system. Ex.
Restoration of watershed costs less than
construction of a water purification plant
-Income: Services provide for increase
in incomes. Ex. Improved water quality
increases # of fish, improves income of
fishers.
-Travel Costs: service demand may
require travel, whose costs can reflect
the implied value of the service. Ex.
Value of ecotourism experience is
sufficient that a visitor is willing to pay to
get there.
-Hedonic Pricing: service demand may
be reflected in the prices people will pay
for associated goods. Ex. Coastal
housing prices exceed prices of homes
that are inland
-Contingent Valuation: service demand
may be elicited by posing hypothetical
scenarios that involve some valuation of
alternatives. Ex. Visitors willing to pay
for increased access to national parks
Major Climatic Periods
Ecological Succession
-Regulating
-Supporting
-Cultural
-Preservation
Natural Ecosystem Changes
Characteristics of Succession Plant
Communities