Ecology Flashcards
Community ecology
studies the interaction of populations
population
group of living things living in a given area
Ecological niche
species’ ecological role within a community
ecological niche examples of components
habitat (living place), use of resources, (temp, food acquisition, etc) overall lifestyle, (mating season, when active (day v night))
each species has its own niche within a given area
Fundamental niche
ideal niche– the niche that an organism occupies in the
absence of competing species
realized niche
modified niche that an organism occupies when competitors are present so there is
no niche overlap
realized niche–if two species need the same resource,…
…they need to learn how to coexist by subdividing
Limiting resource-
environmental resource that may
restrict ecological niche of species
limiting resource examples
temp extremes, precipitation amounts
When does competition occur?
when two or more individuals attempt to use the same essential resource, such as food, water, living space, sunlight
Intraspecific competition
competition among individuals of same species
Interspecific competition
competition between different species
Competitive exclusion principle
one species excludes another from its niche as a result of
interspecific competition. if one’s better, the other species will die out
Resource partitioning
two different species may be able to coexist if their niche differs from one another in slightly different ways
Character displacement
when two similar species living in the same area start to
diverge from one another in certain traits–start to evolve to act differently, helps them survive together
Character displacement–darwin’s finches
When G. fuliginosa and G. fortis live separately, each has an
intermediate sized beak
When the two species live together on the same island, G. fuliginosa has a smaller beak (to crack smaller seeds) and G. fortis has a larger beak (to crack larger seeds).
Predation
consumption of one species, the prey, by another species, the predator
Coevolution
interdependent evolution of two interacting species
How is chemical protection achieved for prey through appearance?
aposematic coloration.
What is another name for aposematic coloration?
warning
coloration
Warning coloration
Being one of a select group that can tolerate a plant’s toxin, eating it, (thereby avoiding competition,) and accumulating the toxin in their tissues. Their coloring signals to predators that they are poisonous.
What are some defensive adaptations to avoid predators
?
Mechanical defenses, group living, cryptic coloration, batesian mimicry, mullerian mimicry
Mechanical defenses
shells of turtles, porcupine quills, presence of spines,
thorns, wax in plants help discourage herbivores
herbivores
eat plants
Why would animals live in groups?
easily spot predators
Cryptic coloration
colors or markings that help prey blend into surroundings
What kind of coloration does a poison dart frog display?
aposematic
What kind of coloration does a canyon tree frog display?
cryptic coloration
Batesian mimicry
non-poisonous species resembles a poisonous species; evolved in order to avoid predation
How does a hawkmoth larva make use of batesian mimicry?
Impersonates green parrot snake
Mullerian mimicry
different species, all of which are poisonous, resemble
one another. Predators therefore easily learn a single aposematic coloration
Example of mullerian mimicry
cuckoo bee and yellow jacket
Symbiosis
intimate relationship or association between members of
two or more species
What does symbiosis usually involve?
one species living on or in another species
Mutualism
- symbiotic relationship in which both partners benefit
nitrogen-fixing bacteria of legumes
bacteria supply the plants with
usable nitrogen, and legumes supply bacteria with energy rich organic molecules–it changes atmospheric to usable
Zooxanthellae
symbiotic algae live inside cells of coral, where they
photosynthesize- provide animal with carbon and nitrogen compounds, and
oxygen. When algae is found in coral, coral grows faster. Corals also
provide algae with waste products like ammonia
Mycorrhizae
associations between fungi and roots of plants- Fungus helps
with absorption of materials, plant provides fungus with
organic materials produced by photosynthesis
Commensalism-
type of symbiosis in which
one species benefits and the other is not harmed or helped
Ex of Commensalism
host tree and epiphytes, which are smaller plants (orchids, ferns) that
attach to the branches of the tree. Tree enables epiphyte to obtain adequate
light, water, and minerals (washed out of tree’s leaves by rainfall). Host
tree is
neither harmed nor helped
Parasitism
symbiotic relationship in which one member, the parasite, benefits, and the other
member, the host, is harmed
ex of parasites
flukes, tapeworms, hookworms
Keystone species
species that have an important role in maintaining the
community even though they may not be very abundant
What happens if a keystone species disappears
If keystone species disappears from a community, other species might
become either more common or they may disappear
where are fig trees keystone
fig tree produces a continuous crop of fruits (even in winter), so they
are a keystone species in tropical rainforests
why are gray wolves keystone
top predators such as gray wolf- when population of wolves decline,
herbivores increased, which decrease vegetation population
Succession
the process of community development over time, which involves
species in one stage being
replaced by different species (generally plants, once they stabilize, animals follow)
beginning of succession
pioneer species
pioneer species
the first to colonize a
newly exposed habitat
pioneer species characteristics (r-selected?)
usually r-selected, reproduce fast, not too many resources needed, Can tolerate harsh conditions such as rocky substrate and nutrient-deficient soils
What replaces pioneer species?
Pioneer species are replaced by stable K-selected species
Ex- grasses, herbs, shrubs, or trees This slows down the rate of succession
final successional stage of constant species composition
climax community
kinds of succession
primary + secondary
primary succession
change in types of species over time in a habitat that
was not previously inhabited by organisms–bare rock surfaces, volcanic lava, 100s-1000s of years
protists
microscopic mostly unicellular simple organisms
succession on rock–first step
Begins with establishment of lichens- helps erode rock into soil
lichens
symbiotic relationship between algae and fungus
what happens as the soil builds up during succession on rock
bacteria, protists, mosses, and other fungi appear, then insects, then other r-selected species such as weeds and grasses, then Replaced by K- selected species-
Secondary succession
quicker, change in types of species that takes place after
some disturbance removes the existing vegetation- soil is
already present
Secondary succession example
Ex- habitats damaged by fires or floods, Succession on abandoned cropland
Succession on abandoned cropland
r- selected species already in soil germinate, Trees follow, type depends on specific region
