ch 14- ecology Flashcards
● Cold winters with snowfall
● Warm, rainy summers
● Largest terrestrial biome
taiga
coniferous forest
● Cold
● Very little precipitation (mostly snow)
● Ground freezes during winters
● Topsoil thaws during summer, but deeper soil is permafrost
(stays frozen)
tundra
● Hot days
● Cold nights
● Extreme temperature fluctuations
● Very little rain
● Plant growth occurs after rainfall
● Animals are often nocturnal and water conservative
(concentrated urine)
● Plants have leather leaves or spines to conserve water
desert
● Mild winters
● Hot, dry summers
● Scattered vegetation, often with small, tough leaves to conserve
water
● Common droughts and fires
chaparral
● Warm summers
● Cold winters
● Moderate precipitation
● Snows during winter
● Trees shed leaves in the winter due to poor growing conditions
temperate dicidious forest
● Cool winters
● Hot summers
● Seasonal rain (less rain than savannas)
● Seasonal droughts and fires
temperate grasslands
● High temperatures
● Small amount of rainfall (seasonal)
● tropical grasslands with diffuse trees
● Seasonal droughts and fires
savanas
● Consistent, hot temperature
● Consistent, heavy rainfall
● Biome with the greatest amount of diversity
tropical rainforest
aphotic zone
No light or photosynthetic
species. Some bioluminescent species. Select
fish can survive off of dead matter descending to
the ocean floor.
disphotic zone
zone: Semi-irradiated with sun (not
sufficient for plants). Bioluminescent species
produce light here.
euphotic zone
Strong irradiance allows for
plant survival and photosynthesis. Closest to surface.
The littoral zone is the area of the
euphotic zone where sunlight penetrates all the way to the ocean floor.
largest earth biome
Aquatic biomes:
Largest of Earth’s biomes (~75% of Earth’s surface).
Photosynthetic algae contribute most of Earth’s
atmospheric O2
Divided into
freshwater biomes (~3%) and
saltwater biomes (~97%).
brackish water
at estuaries where salt water meets freshwater
eutrophication
process whereby a body of
water becomes enriched with minerals and nutrients. This can lead to an algal bloom, a rapid increase in the population of algae (photosynthetic eukaryotes) and/or cyanobacteria (photosynthetic prokaryotes).
Algal blooms lead to the depletion of oxygen in the water, which can kill off aerobic organisms in the area (e.g., fish), damaging natural aquatic
ecosystems.
what causes eutrophication
Eutrophication is often a result of industrial nitrogen-rich fertilizer use. Nitrogen-rich fertilizer can dissolve in rain water, eventually accumulating in an aquatic biome, supporting the growth of algal blooms.
keystone species
maintains ecological balance
despite low abundance (eg. keystone predator
hunts other animals and prevents overabundance).
secondary succesion
occurs on terrain that has
supported life previously, and has had destruction
following a disturbance (e.g., flood, fire). Follows a
similar pattern as primary succession but begins
with grasses & shrubs.
primary succession
occurs after a large disturbance
in an area that has never supported life. Begins with a
pioneer species (e.g., lichen, fungi, algae).
The order of organisms colonizing is:
pioneer species → thin soil → vascular plants (grasses,
shrubs) → larger plants (trees) → animals
Eventually a climax community results. A steady
state is reached and a balance of species is achieved.
ecological succession
is the predictable process
where an ecological community develops and
changes over time. Occurs in a new habitat or after a
disturbance.
malthus
scientist best known for his principle
of population theory. This theory proposes that the
human population increases geometrically (2, 4, 16,
132..) while food production increases arithmetically
(2, 4, 6, 8…) and will not be able to keep up with
population growth.
Type II survivorship species:
● Mortality rate is roughly constant throughout the organism’s life span (survival chances do not significantly increase or decrease at any stage of
life).
● Examples: Many birds, small mammals, and some reptiles.
r- selected species
● Type III survivorship curve.
● Produce a high number of offspring with lower survival rates.
● Short gestation periods with quick development and early maturation.
● Greater number of offspring ensures some will survive, despite low parental care and unstable environmental conditions
● Population size fluctuates wildly. Population densities well below carrying capacity of the environment.
● Examples: Insects, frogs.
k- selected species
● Type I survivorship curve.
● Produce fewer offspring with higher survival rates.
● Long gestation periods with slow development and late maturation.
● High parental care and investment in fewer offspring to ensure survival and competitive success.
● Population size is relatively stable and near the carrying capacity of the environment.
● Examples: Elephants, humans.
