DAT Ecology Flashcards
Abiotic factors
nonliving factors (temperature, climate, light,
water availability, and topology.0
Photic zone
zone in water
where light penetrates.
Aphotic zone
zone in water has
almost no light penetration.
Biotic
all living things that directly or
indirectly influence the life of the organism.
Population
a group of individuals of the same
species living in the same area.
Community
a group of populations living in
the same area.
Ecosystem
describes interrelationships
between organisms in a community and their
physical environment.
Biosphere
combination of all the ecosystems
of the earth. The biosphere includes the
atmosphere, hydrosphere, lithosphere, and
geosphere as well.
Habitat
type of place where an organism
usually lives. The habitat includes all the other
organisms present as well as the physical and
chemical environment.
Niche
this describes all the biotic and abiotic
resources in the environment used by an
organism.
Dispersion
- describes how individuals
in a population are distributed. The
dispersion may be clumped, uniform, or
random
Survivorship curves
how mortality of
individuals in a species varies during
their lifetimes.
Type I SURVIVAL curve
most individuals survive to
middle age but mortality increases
quickly in old age. Humans have a
type I survivorship curve
type ii survival curve
the probability of survival is
generally constant and independent
of age. Hydras have a type II
survivorship curve
Type III survivorship curve
most individuals die young,
with few surviving to reproductive
age and beyond.
Biotic potential
the maximum
growth rate of a population under
ideal conditions (unlimited resources
and no restrictions).
Carrying capacity (K)
the
maximum number of individuals of a
population that can be sustained by
a habitat
Limiting factors
elements that
prevent a population from reaching
its full biotic potential.
density dependent limiting factors
- the
limiting effect becomes more
intense as the population density
increases.
Density-independent limiting factos
limiting
effect’s intensity occurs
independently of the density of the
population.
Intrinsic rate
when the reproductive
rate (r) is at its maximum (biotic
potential)
Exponential growth
occurs whenever
the reproductive rate (r) is greater than
zero. This creates a J-shaped curve.
viii.Logistic growth
occurs when limiting
factors restrict the size of the population
to the carrying capacity of the habitat.
viii.Population cycle
population size
fluctuates in response to varying effects
of limiting factors. When the population
grows over carrying capacity, the
population may then be limited to a size
lower than the initial K due to the
damage caused to the habitat.
K-selected population
members have low
reproductive rates with longer
maturation times, and their size is
roughly constant at K (e.g., human
population).
R-selected population
- these species
have rapid exponential population
growth. They have numerous offspring
that are small and have fast maturation,
so little parental care is needed (e.g.,
bacteria).
lag phase,
when
bacteria are adapting to growth conditions.
log phase
` is the exponential growth
of the population as it doubles with every time
period (using log # produces a straight line
here).
stationary phase,
the growth rate equals the death rate
due to growth-limiting factors.
Ecological footprint
- the aggregate land and
water area necessary to produce all the
resources to sustain an individual/group of
people and absorb all their wastes.
Shannon diversity index
species diversity is
measured by the Shannon diversity index. The
higher the value, the more diverse the community
Competitive exclusion principle (Gause’s
principle)
when two species compete for
exactly the same resources (or occupy the same
niche), one is likely to be more successful.
Resource partitioning
when two species
occupy the same niche but pursue slightly
different resources, individuals can minimize
competition and maximize success through
resource partitioning.
Character displacement (niche shift)
certain traits
allow for more success in obtaining resources in
their partitions. This reduces competition and
increases the divergence of features. Thus,
character displacement occurs where unique
differences among species diverge even more
when they coexist near each other.
Realized and fundamental niches
fundamental niche is the area
that a species could potentially survive in. The
realized niche is the area that the species
actually lives in due to factors such as
competitors.
Parasitoid
this is an insect that lays its
eggs on a host (insect or spider).
Symbiosis
an intimate, often permanent
association between two organisms.
Facilitation
some species have positive effects
on the survival and reproduction of another
species without necessarily living in direct and
intimate contact for symbiosis.
Saprophytism
saprophytes are protists and
fungi that decompose dead organic matter
externally and absorb nutrients.
Intraspecific interactions
competition
between members of the same species, and it
is influenced by disruptive (competition) and
cohesive (reproduction and protection from
predators and weather) forces.
Interspecific
competition
between members of different
species, and is ultimately negative for bothsince they are competing against each other for
resources.
Interference competition
occurs directly
between individuals via aggression, etc.
allelopathy,
the production of
biochemicals by an organism to influence the
growth/survival/reproduction of other
organisms.
Exploitation competition
occurs indirectly
through the depletion of a common resource.
Apparent competition
occurs between two
species preyed upon by the same predator.
osmoregulation freshwater fish
these fish live in a
hypo-osmotic environment which causes
an excess intake of water. Thus, the fish
seldom drink and excrete dilute urine
osmoregulation saltwater fish
live in a hyper-osmotic
environment. The fish are constantly
drinking and excreting salt across their
gills
Arthropods osmoregulation
secrete solid uric acid
crystals to conserve water
Plants osmoregulation
possess waxy cuticles on the
leaf surface and stomata. Stomata are
on the lower leaf surfaces only. Leaves
are shed in winter.
Cold-blooded (poikilothermic)
vast
majority of plants and animals are
poikilothermic. This means their body
temperature is close to that of their
surroundings, so their metabolism is
radically affected by the environmental
temperature
Warm-blooded (homeothermic)
homeothermic organisms make use of
the heat produced by respiration.
Physical adaptations like fat, hair, and
feathers retard heat loss. Mammals and
birds are warm-blooded
Secondary compounds
these are toxic
chemicals produced in plants that
discourage would-be herbivores
because they are toxic to herbivores.
Aposematic coloration (warning
coloration)
a conspicuous pattern or
coloration of animals that warns
predators that they sting, bite, taste
bad, are poisonous, or are otherwise to
be avoided
Mullerian mimicry
occurs when
several animals, all with some special
defense mechanism, share the same
coloration. This way, the predator
only has to learn that one pattern is
bad instead of lots of variants.
Batesian mimicry
occurs when an
animal without any special defense
mechanism mimics the coloration of
an animal that does possess a
defense. Coloration, camouflage,
mimicry, etc. are passive defenses.
Ecological succession
change in
composition of species, organisms and
vegetation over time. It describes how one
community is gradually replaced by another
group of species.
Primary succession
occurs on substrates that
have never previously supported living things,
such as volcanic islands, lava flows, or rock left
behind by retreating glaciers.
Secondary succession
begins in habitats where
communities were entirely or partially
destroyed by damaging events, such as fire,
flood, insect devastation, overgrazing, forest
clearing, construction sites, etc. The habitat
previously supported life, so unlike primary,
secondary succession begins on substrates that
already bear soil.
dominant species
the species in a
community that is the most abundant or
collectively has the highest biomass.
Keystone species
are not usually abundant but
exert a strong control on their community
structure not by their high quantity, but through
their pivotal ecological role.
Ecosystem engineers,
a.k.a. foundation
species, dramatically alter their physical
environment.
apex predator
predator sits at the top of the food
chain and no other creatures predate it
Primary producers
autotrophs that
convert the sun’s energy into chemical
energy. Primary producers include
plants, photosynthetic protists,
cyanobacteria, and chemosynthetic
bacteria. Their efficiency from sunlight is
only about 1% of the energy available to
them
Primary consumers
these are
herbivores. They have long digestive
tracts with greater surface area so there
is more time for digestion.
Secondary consumers
these are
primarily carnivores, and they eat
primary consumers
Tertiary consumers
they are secondary
carnivores, and they eat secondary
consumers
Detritivores
- consumers that obtain
energy by consuming detritus. Detritus
is nonliving organic material.
Ecological pyramids
show the relationships
between trophic levels, or biomass.
Ecological/trophic efficiency
describes the
proportion of energy represented at one
trophic level that is transferred to the next.
Food chain
linear flow chart of who’s eaten by
whom.
Food web
is an expanded, more complete
version of a food chain showing major plants,
animals that eat the plants, animals that eat the
animals, detritivores, etc.
Assimilation
the process through which
elements are incorporated by terrestrial plants
and animals.
Carbon cycle
Assimilation is done by plants when they
use CO2 in photosynthesis, and by
animals when they consume plants (this
is carbon fixing because the carbon is
reduced from its inorganic form of CO2
to organic compounds). Release of CO2
occurs through respiration,
decomposition, and when organic
material is burned
Nitrogen cycle
reservoirs are
atmospheric nitrogen (N2) and soil
(NH4+, NH3, NO2, NO3). Assimilation
occurs when plants absorb nitrogen as
either NO3-
or NH4+ and when animals
obtain nitrogen by eating plants/
animals.
Nitrogen fixation
- this is when
atmospheric nitrogen (N2) is
converted into organic nitrogen
(NH4+) through nitrogen-fixing
bacteria in the soil. Nitrogen can
also be fixed by lightning and be
converted into nitrogen oxides
(NOx)
Nitrification
this is when
ammonium (NH4+) is converted to
nitrite (NO2-
) followed by the
conversion of nitrite to nitrate (NO3-
)
by nitrifying bacteria
ammonium formula
NH4+
nitrites
nh2-
nitrates
NH3
Phosphorus cycle
reservoirs for phosphorous are rocks
and ocean sediments because erosion
transfers phosphorous to the water and
soil. Assimilation occurs when plants
absorb inorganic phosphate (PO43-)
from the soil and when animals obtain
organic phosphorus when they eat.
Release of phosphorous occurs when
plants and animals decompose, and
when animals excrete phosphorous in
waste products
Chaparral
this terrestrial biome along
the California coastline is characterized
by wet winters, dry summers, and
scattered vegetation (dense, spiny
shrubs). California fires happen here
Benthic zone
- this is the lowest
layer of a body of water, including
the sediment surface and sub-
surface layers. In deep ocean water,light does not penetrate. Most
organisms here are scavengers
and detritivores.
Pelagic zone
the water that is
neither close to shore nor close to
the very bottom.
Epiplagic
- this is the surface
layer of water and the only
photic zone since there is
enough light for penetration.
Nearly all primary production
of the ocean occurs here
Mesoplagic
an aphotic zone,
so there is not enough light
for photosynthesis. There is
minimal oxygen here
Bathypelagic
aphotic zone
and pitch black. There is no
plant life, and most organisms
here consume detritus that
comes down from above
Abyssopelagic
also an
aphotic zone. It is cold, high
pressure, and most species
have no eyes due to the lack
of light
Hadopelagic
most life here
exists in hydrothermal vents.
This zone is aphotic as well
Biological magnification
- as one organism
eats another, toxins (e.g., pesticide) become
more concentrated at each higher trophic level.
Bioremediation
using organisms to detoxify a
polluted ecosystem.
Biological augmentation
using organisms to
add essential materials to a degraded
ecosystem.
biological
hotspot
small area with numerous endemic
species and a large number of endangered and
threatened species.
Extinction vortex
a small population size
leads to inbreeding, and genetic drift has a
significant effect. The loss of genetic variability
leads to reduced fitness and lower survivability.
Intermediate disturbance hypothesis
suggests
that low to moderate levels of disturbances
actually increase species diversity, while high
levels of disturbances reduce diversity.
