Ecology Flashcards
What is ecology?
Study of the abundance and distribution of organisms.
Biogeography
Emphasis on historical events that affect organism distribution and abundance.
Define Dispersal and give two reasons
Movement away from high population centers or origin, due to natural movement, or due to human activities.
Biotic Homogenization
Making more of the same
Kinlan and Gaines 1/4
The scale of dispersal is highly variable among taxa
Kinlan and Gaines 2/4
Multiple trophic levels are involved in dispersal.
Kinlan and Gaines 3/4
Herbivores often disperse further than plants
Kinlan and Gaines 4/4
Dispersal is greater in water than terrestrial plants.
Why might species X not be in a given area? (General 4 topics)
Dispersal, Behavior, Biotic Factors, Abiotic Factors
Biotic Factors (4 main)
Predation, parasitism, competition, disease
Behavior
Habitat selection, choose not to live there
Abiotic Factors
water, oxygen, salinity, pH, soil nutrients, temperature, sunlight, wind
A biome can be defined by 2 major variables:
Temperature and Precipitation
Levels of Ecological Research
Population, community, ecosystem, landscape, global
Population Ecology
explores biotic/abiotic factors and their effect on size, density, distribution, and age of populations
Define a population
same species, same place and time
Define dispersal vs. dispersion
dispersal= movement of a population, dispersion=pattern of population
Clumped dispersion
spurred by resource location, mating, social interation.
Uniform dispersion
spurred by territorial demands, and competition within species
Random dispersion
null model
Demography
study of population attributes like sex ratio and age
Pyramid diagrams: Urn shaped (larger on top)
non growing/declining population
Pyramid diagrams: Pyramid shaped
rapidly growing population
Pyramid diagrams: Bell shaped (large in middle)
slow, non growing population
Generation Time
time needed to mature a generation
Generation time is linked to ___ ___.
Generation time is linked to body size.
Cohort
group of individuals of the same age
Survivorship
tracks the number of individuals in a cohort over time
Survivorship Types
low y, high o | constant death rate | high y, low o.
Under idealized conditions, all organisms are capable of _____ growth
exponential
Density Independent inhibition
natural disasters, weather
Density dependent inhibition
normal, biological factors such as overcrowding, or consumption of a resource
Logistic growth
a more realistic growth model containing a carrying capacity, K
Carrying capacity
limit of growth on a population
Interspecific Interactions
Interactions between species, such as predation, symbiosis, competition for resources…
Intraspecific interactions
interactions between members of the same species.
Predation can be considered an ____ ____.
Predation can be considered an evolutionary force.
In the coevolutionary arms race, _____ are always a little ahead of ____.
prey are ahead of predators, because life is more important than a meal.
Defenses: Cryptic Coloration
disguises, and can interfere with other animal’s senses.
Defenses: Aposematic Coloration
bright colors indicate poison (dart frog)
Defenses: Batesian Mimicry
harmless species mimic harmful ones.
Defenses: Mullerian Mimicry
harmful species mimics another harmful one (double l’s)
Defenses: Hard to eat
self explanatory
Defenses: Group
let someone else be caught, and predator mobbing
Defenses: Scare of confuse
self explanatory: eyespots, ink…
Defenses: Vigilance
self explanatory
Defenses: Active Defense
offense
Defenses: Fleeing
fleeing
Symbiosis: Parasitism
(+/-)
Symbiosis: Mutualism
(+/+)
Symbiosis: Commensalism
(+,0)
Competitive Exclusion Principle (CEP)
2 species sharing limited resources cannot coexist forever.
(Intra/Inter) species competition is more common
Intraspecies competition is more common because organisms share the same resources when part of the same species.
Niche
sum of total organism use of environment resources, including habitat, food, temperature, reproduction.
CEP Version II
No 2 species can have the same niche if resources are limited.
Over time, natural selection will ___ ___.
decrease competition.
Character Displacement
tendency for characteristics of sympatric populations to diverge more than allopatric populations. This is because of the CEP.
Definition of Community
group of populations in the same area/habitat.
Trophic Structure
who eats what/whom, food chains, food webs.
Top Down Control
Predators dictate lower trophic levels.
Bottom Up Control
Trophic levels controlled by abundance of primary producers/ nutrients
Trophic Cascades
Indirect effect of predators on lower autotrophic levels.
Dominant Species
most abundant, great biomass
Keystone Species
exert strong ecological control by their niches, often the main predator., example, beaver.
Biodiversity
variety of life in all forms, genetics, and ecosystems
Richness
total number of species in community
Evenness
distribution of individuals among different species
Biodiversity Crisis
extinctions increasing, and trophic downgrading.
Causes for Modern Extinction: Habitat Destruction
loss of habitat, and fragmentation
Fragmentation
destruction of habitat decreases possible gene flow.
Causes for Modern Extinction: Introduced Species
invaders can alter habitat, reduce/displace native species via competition, predation, etc.
Invasive Species must have:
wide environmental tolerances, large native range, high population growth, predator resistance.
Overexploitation
harvesting at higher rates than population growth.
Solutions to Biodiversity Crisis
awareness, biodiversity reserves, restoration, and policy/economics.
Ecosystem Level Ecology
focus on what organisms do, energy matter, chemical cycling,
Ecosystem Level Ecology view on organisms
how they obtain energy, how that energy is transferred.
Photosynthesis/Respiration
CO2+H2O–>G + O2
Energy Pyramids
decreases by 10% each level up.
Nutrients essential for growth
C,N,P, H2O
