Biology 100 Unit 24 Flashcards
– The expanding human population threatens
– ________________________
– ________________________
Biodiversity
The loss of natural resources
Healthy ecosystems: (4 things)
– Purify air and water – Decompose wastes – Recycle nutrients
– Pollinate crops
An organism’s biotic environment includes
– Other individuals in its own population
– Populations of other species living in the same area
– An assemblage of species living close enough together for potential interaction is called a ____________________.
community
are interactions between species. Classified according to effect organisms involved
Interspecific interactions
_____ interactions occur when two populations in a community compete for a common resource.
-/-
_____ interactions are mutually beneficial, such as between plants and their pollinators.
+/+
_____ interactions occur when one population benefits and the other is harmed, such as in predation.
+/-
In interspecific (between species) competition, the population growth of a species may be limited by – The population densities of \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ – By the density of its \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
competing species (-/-) own population
An ecological ___________ is the sum of an organism’s abiotic and biotic resources in its environment.
niche
Interspecific competition occurs when
the niches of two populations overlap.
The _____________________________ states that if two species have an ecological niche that is too similar, the two species cannot coexist in the same place.
competitive exclusion principle
These different species of warblers have an ecological niche that overlaps, leading to ___________________
interspecific competition (+/-) they cant live together
In mutualism, ___________________________________. An example of mutualism includes reef-building corals and
photosynthetic dinoflagellates.
both species from an interconnection
The photosynthetic dinoflagellates
– gain shelter in the cells of each coral polyp,
– produce sugars used by the polyps, and
– provide at least half of the energy used by the coral animals.
– ___________________________
both organisms benefit
Numerous adaptations for predator avoidance have evolved in
prey populations through natural selection.
– Cryptic coloration is ___________________ – A way for prey to hide from predators
camouflage
– A warning coloration is a ___________________
– Way to warn predators that an animal has an
effective chemical defense
brightly colored pattern
– Mimicry is a form of defense in which one _______ ___________________.
animal looks like another species
is the consumption of plant parts or algae by an animal.
Herbivory (+/–)
Herbivores and plants undergo
coevolution,
coevolution:
– a series of reciprocal _____________________
________________________,
– in which change in one species acts as a new selective force on another.
evolutionary adaptations
A plant whose body parts have been eaten by an animal must
expend energy to replace the loss.
Thus, numerous defenses against herbivores have evolved in plants.
– Plant defenses against herbivores include
– ______________________
– ______________________
- spines and thorines
- chemical toxins
Plants and animals can be victims of
parasites and pathogens
__________ an organism that lives in or on a _______
from which it obtains nutrients
parasites, host
____________ include nematodes and tapeworms.
Internal parasites
______________ include mosquitoes, ticks, and aphids.
External parasites
are disease-causing microscopic parasites
Pathogens
examples of pathogens: – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
- bacteria
- viruses
- fungi
- protists
is the feeding relationships among the various species in a community.
Trophic structure
is the feeding relationships among the various species in a community.
Trophic structure
A community’s trophic structure determines the passage of energy and nutrients from plants and other photosynthetic organisms such as
– __________________
– __________________
herbavors
predators
The trophic level that supports all other trophic levels consists of autotrophs, also called _______________.
producers
All organisms in trophic levels above the producers are heterotrophs, or __________________.
consumers
________ are called herbivores, which eat plants.
Primary consumers
Above the level of primary consumers are
carnivores, which eat the consumers from the level below.
– Secondary consumerstertiary consumers quaternary consumers
________ is lost as it moves each trophic level, limiting the number of trophic levels an ecosystem can sustain.
Energy
Detritivores, which are often called scavengers, consume ______________, the dead material left by all trophic levels.
detrus
which are often called scavengers, consume detrus the dead material left by all trophic levels.
Detritivores,
Decomposers are _____________________, which secrete enzymes that digest molecules in organic material and convert them into inorganic forms.
prokraryotes and fungi
are prokraryotes and fungi which secrete enzymes that digest molecules in organic material and convert them into inorganic forms.
Decomposers
both Detritivores, and Decomposers
recycle nutrients and make them available to producers
A _________ is a network of interconnecting food chains.
food web
– In food Webs
– consumers may eat more than one type of producer
– several species of consumers may feed on the same species of producer.
A food web shows mutliple interactions among producers, predators, and prey
which is a better representation of what occurs in nature.
is concerned with the number of different species and their relative abundance in a community
Species diversity
Species diversity is important in ecosystems because it makes them more productive and enables them to ____________________________________________.
rebound much faster if faced with a disturbance
Although each of these woodlots has the same number of species, ______________________________________.
the more evenly distributed lot is more diverse
have a disproportionate impact on diversity
Keystone species
A _____________________ is a species whose impact on its community is larger than its biomass or abundance indicates and
– occupies a niche that holds the rest of its community in place.
keystone species
Examples of keystone species in marine ecosystems include – Pisaster sea stars because they keep the population of
mussels in a marine environment in check.
– WithoutPisaster,_______________________________ ____________________________________________.
mussels would completely dominate many marine habitats
are events that damage biological communities.
Disturbance
– Disturbances include
storms, fires, floods, droughts, overgrazing, or human activity.
– The types, frequency, and severity of disturbances varies from
community to community.
After a disturbance, an ________________________ follows.
ecological succession
________________________ is the colonization of a species in a given habitat after a disturbance.
ecological succession
– Primary succession begins in a virtually lifeless area with
no soil. Ex: _____________________________
volcanos and glacial activity
– Secondary succession occurs when a disturbance destroys an existing community but leaves the soil intact.
– Ex:_____________________________________
fires and floods
________________________: are organisms that have been introduced into non-native habitats by human actions and
invasive species
– have established themselves at the expense of native communities.
– The absence of natural enemies often allows rapid population growth of _____________
invasive species.
Examples of invasive species include the deliberate introduction of
– rabbits into Australia
– cane toads into Australia.
include essential elements and chemicals needed throughout different levels of an ecosystem. They include
biogeochemical cycles
Biogeochemical cycle include
both biotic and abiotic components
is the major ingredient of all organic molecules
carbon
Carbon is found in:
– ____________________
– ____________________
– _____________________________________
- atmosphere
- fossil fuels
- dissolved Carbon components in ocean
The return of CO2 to the atmosphere by respiration closely balances _______________
The carbon cycle is affected by burning wood and fossil fuels.
its removal by photosynthesis.
In the phophoric cycle:
Organisms require phosphorus for ___________________ _________________________________.
nucleic acids, phopholipids, and ATP
In the phophoric cycle:
The phosphorus cycle does not have
an atmospheric component.
In the phophoric cycle:
are the only source of phosphorus for terrestrial ecosystems.
Rocks
In the phophoric cycle:
Plants absorb phosphate ions in the soil and build them
into organic compounds.
In the phophoric cycle:
Phosphates are returned to the soil by ________________
decomposers
In the phophoric cycle:
_______________in aquatic ecosystems are typically low
enough to be a limiting factor.
Phosphate levels
________________________________
– essential to the structure and functioning of all organisms, and
– a crucial and often limiting plant nutrient.
Nitrogen is an ingredient of proteins and nucleic acids,
Nitrogen has two abiotic reservoirs: ___________________________________________ ___________________________________________
- the atmosphere is 80% nitrogen
- soil
Although agricultural and other managed ecosystems are necessary to supply our needs,
we also depend on services provided by natural ecosystems.
some Healthy ecosystems – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ – \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
- supply fresh water and food
- recycle nutrients
- decompose waste
- regulate air quality
converts N2 to compounds of nitrogen that can be used by plants and
Nitrogen fixation
In Nitrogen fixation:
– is carried out by some _______________________.
bacteria
