Ecology Flashcards
Abiotic factors:
-nonliving elements of an
ecosystem (eg. temperature, water, light).
Biotic factors:
- living elements of an
ecosystem (eg. plants, animals, etc.).
Species
-: a group that can interbreed and
have viable, fertile offspring.
Population:
- a specific species living in a
specific location.
Habitat:
- the type of place where a specific
organism lives. Includes other organisms
(biotic) and physical aspects (abiotic).
Ecological community:
- all populations in a given area.
Ecosystem:
- all the organisms in an ecological
community (biotic), and the abiotic factors
interacting within it.
Biosphere:
- all ecosystems on Earth, their
interactions with each other and the
lithosphere, geosphere, hydrosphere,
atmosphere.
Density-dependent factors
- depend on population density (eg. disease, resource
competition).
Density-independent factors
- do not depend on population density (eg. climate, weather).
Ecological Niche
- An organism’s niche is the biotic and abiotic
resources it uses. Its realized niche is where it
truly lives and its fundamental niche is the full
range of environmental conditions where it could
survive.
Gause’s Law (competitive exclusion principle):
- Two species cannot occupy the same niche and
maintain population levels: one will outcompete
the other. Resource partitioning allows species
to coexist.
Biological Interactions: competition
- In competition (short-term interaction), 2 species
compete for the same resources. - includes:
1) intraspecific competitions
2) exploitation competition
3) apparent competition
4) interspecific competition
Intraspecific competition
- occurs between members of the same species (eg. two rabbits
competing for carrots).
Exploitation competition
- is indirect and occurs when resources are depleted. (eg.
cheetahs deplete gazelle population, affecting lions).
Apparent competition
- occurs when one predator preys on two species.
Interspecific competition
- occurs when one species directly prevents the establishment of
another species that would compete for a mutual resource. - includes: 1) allelopathy
Allelopathy
- is a type of interspecific competition used by plants where a toxic chemical is secreted to prevent such establishment; common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms.
Symbiosis (living together)
-is a close, long-term interaction between two organisms (symbionts).
- includes: 1) Mutualism, 2) Commensalism, and 3) Parasitism
Mutualism (+/+)
- both organisms benefit (eg.
oxpecker bird eating ticks off rhino).
Commensalism (+/0)
- : one organism benefits
and the other is unaffected. (eg. jackal eating
tiger’s leftovers).
Parasitism (+/-)
-: one organism benefits at the
other’s expense. (eg. tapeworm in human
gastrointestinal tract).
Food chain:
- linear depiction of what eats
what (eg. carrot → rabbit → fox → lion).
Food web:
- expanded food chain depicting
interconnections between food chains.
Trophic level:
- an organism’s position within
a food chain or food web.
Ecological pyramid:
- Graphical representation of the accumulation of
biomass at each trophic level.
Autotroph
- produces organic compounds
from abiotic factors (sunlight, water, CO2, etc.) - Autotrophs are able to fix carbon, therefore
they use CO2 as its primary carbon source.
Heterotroph:
- must ingest organic
compounds to generate energy & survive.
-Heterotrophs, however, are unable to fix carbon
and derive its carbon from organic compounds.
Lithotroph:
- utilize inorganic compounds as
their electron donors during cell respiration.
Predation:
- relationship between predator
(hunter) and prey (hunted - plant or animal).
Herbivore:
- plant eater. Has longer intestinal
tract and cecum to eat plants.
Carnivore:
- meat eater.
Omnivore:
- plant and meat eater.
Invasive species
- non-native species that outcompetes native species and overtakes
ecosystem.
Noninvasive species
- : non-native species that survives in but does not overrun an ecosystem.
Naturalized species:
- a type of non-native species that spreads beyond origin that
showcases sufficient reproduction to maintain
its population.
Exotic species:
- a type of non-native species
that lives outside of its native-distributional
range due to human activity.
Primary producers
- , at the lowest trophic level,
are autotrophs undergoing energy production
(eg. photosynthesis) to generate the biomass of
an ecosystem. Consumers (higher trophic levels)
eat producers or other consumers.
Primary consumers (often herbivores)
- are just above producers. Secondary consumers
(carnivores) prey on primary consumers.
Tertiary consumers prey on secondary
consumers.
An apex predator
- is at the top of the chain
(tertiary consumer or higher).
Only ~_____% of energy stored in a trophic level is
converted to _____ tissue in the next trophic
level as energy transfer is _____ between
trophic levels. As energy moves up each trophic
level in the pyramid, ~_____% of it is lost as heat.
1) 10%
2) organic
3) inefficient
4) 90%
Scavengers (carnivores or herbivores)
- consume other dead animals (or plants). eg. vultures, some
beetles.
Decomposers (saprophytes, fungi,
detritivores)
- breakdown and recycle dead
plant/animal material.
Saprophytes (plants,fungi, microorganisms)
-consume dead or decaying organic material, and work with
scavengers in organic recycling.
______ (most important decomposers) and some ______ decompose organisms, forming ______ (feces and decomposing matter).
1) Fungi
2) bacteria
3) detritus
_____ (worms and slugs) consume detritus, exposing more
organic material for decomposers.
1) detrivores
We can further classify organisms by their energy
and carbon source:
1) Phototroph
Energy Source: Light
Carbon Source: CO2
2) Chemotroph
Energy Source: inorganic compounds
Carbon Source: CO2
3) Photoheterotroph
Energy Source: Light
Carbon Source: organic compounds
4) chemoheterotroph
Energy Source: inorganic compounds
Carbon Source: organic compounds
‘Photo-’ : Organism derives its energy from light.
‘Chemo-’: Organism derives its energy from
inorganic compounds (hydrogen sulfide, ferrous
iron, etc.).
Population dynamics
- explores how populations change in space and time and how they interact
with their environment. - includes: 1) biotic potential and 2) carrying capacity
Biotic potential
-: a species’ ability to undergo
its highest population growth (highest births,
lowest deaths) when conditions are ideal.
Carrying capacity:=
- the maximum population
size an ecosystem can sustain.
r/K selection theory: K-selected Species
- large offspring, long time to mature, significant
parental investment, high survival to reproductive
age (eg. humans, large mammals). Demonstrated
by a type I survivorship curve.
refer to page 130 DAT bootcamp for graphical image
r/K selection theory: R-selected Species
- abundant, small offspring, mature quickly, no parental investment, many do
not survive to reproductive age (eg. bacteria, insects, species with free swimming larvae). Demonstrated by a type III survivorship curve. - In a type II survivorship curve, survival probability is constant regardless of age (eg. hydra, some birds & small mammals, lizards).
refer to page 130 DAT bootcamp for graphical image
Malthus’ Principle of Population Theory
- scientist; 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.
Ecological succession
- is the predictable process
where an ecological community develops and
changes over time. Occurs in a new habitat or
after a disturbance.
Primary succession
- occurs after a large disturbance in an area that has never supported
life. Begins with a pioneer species (eg. 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.
Secondary succession
- occurs on terrain that has
supported life previously, and has had destruction
following a disturbance (eg. flood, fire). Follows a
similar pattern as primary succession but begins
with grasses & shrubs.
A keystone species
- maintains ecological balance
despite low abundance (eg. keystone predator
hunts other animals and prevents
overabundance).
__________
Largest of Earth’s biomes (~_______% of Earth’s surface). _______ contribute most of Earth’s atmospheric O2.
Divided into _______ (~3%) and _______ (~97%). _______ are areas
where freshwater meets saltwater. This mixing of salt and freshwater is known as _______.
1) aquatic biomes
2) 75%
3) Photosynthetic Algae
4) freshwater biomes
5) saltwater biomes
6) estuaries
7) brackish wash
Layers of the ocean are divided based on the
amount of sunlight received:
1) Euphotic Zone
2) littoral zone
3) Disphotic Zone
4) Aphotic zone
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.
Disphotic zone
- semi-irradiated with sun (not
sufficient for plants). Bioluminescent
species produce light here.
Aphotic zone:
- no light or photosynthetic
species. Some bioluminescent species. Select
fish can survive off of dead matter
descending to the ocean floor.
Terrestrial Biomes
refer to pg 132 DAT Bootcamp for chart
