Unit 8: Ecological Interactions Flashcards
Define
Ecology
The study of living organisms (biotic) and their environment (abiotic)
List
Levels of Ecological Organization
Individual
Population
Community
Ecosystem
Biome OR Landscape
Biosphere
Define
Population
A group of individuals that have gene flow
Define
Community
All populations living and interacting in a given area
(and also a really hilarious TV show)
Define
Ecosystem
The living and nonliving aspects of a particular environment
List
Abiotic factors that influence ecosystems
Availability of sunlight
Temperature
Availability of water
What organisms are most important in an ecosystem?
Autotrophs
All other organisms depend on their ability to capture energy and make organic molecules
Define
Biome
All ecosystems on Earth that share similar biotic and abiotic factors
What two factors determine terrestrial biomes?
Temperature and precipitation
List
Terrestrial biomes and basic characteristics of each
- Rainforest: Consistent temperature (warm) and rainfall (a lot)
- Savanna: Hot with little precipitation
- Desert: Dry (Subtropical = hot and dry; Arctic tundra = cold and dry)
- Chaparral: Hot, dry summers and short rainy season
- Grasslands: Temperature fluctuates seasonally; fairly dry
- Temperature forests: Temperature fluctuates seasonally; consistent rainfaull
- Boreal forests: Cold and dry winter with short periods of warmth in the summer
List
Major aquatic biomes
Marine (saltwater) - intertidal, coral reefs, oceanic zones
Freshwater - lakes, ponds, rivers, wetlands
Define
Climate
Long term, predictable conditions
Define
Weather
Short-term conditions (daily or seasonal) in an area
Define
Demography
Statistical descriptions of populations
How are populations described?
Total size (N)
Distribution
Density
Composition (age, sex, etc)
How can population size be determined?
Counting
Quadrats
Mark & Recapture
Describe
Quadrat use
Random locations selected
Quadrat of specific size is set at random location
Individuals within the quadrat are counted
Total population extrapolated from quadrat samples
Describe
Mark & Recapture
Animals are caught and tagged
Tagged animals are released
New group is caught
Number of tagged animals is compared to total number in sample
Population (N) = (Total number marked * Sample size) / (Number marked from the sample)
List the types of
Dispersion patterns
Uniform
Random
Clumped
Define
Survivorship
Ratio of individuals that survive over a specified time period compared to the initial population
Often given as a rate per 1000
Define
Mortality rate
Ratio of individuals that die over a specified time period compared to the initial population
Often given as a rate per 1000
Describe
Survivorship curve (generic)
A graph that shows the survivorship of a population by age
Values near 100 indicate a low mortality, whereas values near 0 indicate that very few survive to the specified age
Describe
Three types of survivorship curves
Type 1: Most individuals that are born survive into adulthood
Type 2: Survivorship drops consistently over life expectancy
Type 3: Most individuals born do not survive into adulthood
Define
Exponential population growth
Population growth with no limiting factors; J-shaped curve
Define
Logistic population growth
Population growth that slows as the population size increases
Outline
Three stages of logistic growth model
1. Exponential phase: The population has few density-dependent factors that limit growth
2. Transition phase: The rate of increase levels off
3. Plateau / Leveling phase: The rate of increase approaches zero and the population levels off
Define
Carrying capacity
The maximum number of individuals that one area can support
Define
Density-dependent limiting factors
Factors that do not affect population growth for very small populations, but have large impact on large populations
List
Density-dependent factors
Intraspecific competition
Disease
Build-up of toxins
Define
Intraspecific competition
Competition between members of one population
Examples: Food / resources, land (territoriality), mates
Define and give examples of
Density-Independent factors
Factors that limit population growth that equally impact populations near zero and near K
Ex: Natural disasters
Define
r (ecology)
Intrinsic rate of increase
The per capita change in population size (per capita birth minus mortality)
Define
ZPG
Zero population growth
r = 0
Define
Life History
How a population’s evolutionary history influences their energy budget
Relate energy acquisition of a population to energy use
Organisms must balance their energy intake and use.
When intake > use, excess energy can be used to grow and reproduce.
Growth, reproduction, and parental care must be balanced to maximize reproductive fitness.
Define
Fecundity
Potential reproductive capacity (idealized)
Relate
Fecundity and parental care
Energy budgets typically mean a population can expend energy on high fecundity but low parental care OR low fecundity with high parental care;
i.e. species typically either make a lot of offspring that mostly die or invest energy in child rearing for relatively few offspring
Describe features of
K selected species
High population (N near K)
Tend to invest in long gestation and parental care for few offspring
Describe features of
r- selected species
Large fluctuations in population size due to changing conditions
Tend to invest in high numbers of offspring instead of parental care
Define
Predation
When animals hunt and kill other animals for food
Define
Herbivory
When animals consume plant materials
List
Defense mechanisms against predation
Escape tactics (speed, loose skin)
Defenses (claws, teeth, protective shells or coats, spikes, etc)
Camouflage
Chemicals (poisons, unpleasant tastes, unpleasant smells)
Behaviors (staying in groups, playing dead)
Aposematic coloration
List
Defense mechanisms against herbivory
Tough tissues
Poisons / foul scents
Spikes / barbs / thorns
Alternative “offerings” or growing near more appetizing plants
Define
Aposematic coloration
Warning colorings
Predators may evolve to associate certain colors with unpleasant tastes, toxins, or smells and then avoid potential prey with those colors
Describe
Batesian mimicry
Evolution of a harmless species to look more like a dangerous species to avoid being preyed upon
Describe
Müllerian mimicry
Convergent evolution of many dangerous prey organisms to look similar, leading to strong aversion by potential predators
Define
Competitive Exclusion Principle
Two species cannot occupy the same niche
Define
Niche
All aspects of a population’s role in an ecosystem
Includes all interactions between the population and other populations, and the population with its environment
Define
Resource partitioning
Two populations with similar niches may divide a resource for which they are competing, and then be able to co-exist within the ecosystem
Define and list the types of
Symbioses
Close and prolonged interactions between individuals of different species
-Mutualism
-Commensalism
-Parasitism
Describe and give examples of
Mutualism
Symbiotic relationship in which both participating species are benefitted
Ex: Anenome and clown fish; bee and flower
Describe and give examples of
Commensalism
Symbiotic relationship in which one species is benefitted and the other is unaffected
Ex: Birds (nesting) and trees
Describe and give examples of
Parasitism
Symbiotic relationship in which one species is benefitted and the other is harmed
Ex: SO MANY!… basically every infection
Define
Foundation species
A species in a community that is integral to the community
Often those that make the usable energy or modify the landscape in such a way that others may inhabit the area
Define
Keystone species
A population in a community that has a major impact on the species richness of that community and which, if removed, would lead to dramatic changes in the composition of the community
Define
Species richness
Number of unique species in a habitat or ecosystem
Define
Invasive species
Non-native species that enter new ecosystems; often lack natural predators and can have rapid population growth that affects native populations in the area
Define
Disturbance
Major changes to a community’s structure and/or composition
Relate species richness and disturbances
Ecosystems with greater species richness are less affected by disturbances and are more able to rebound after disturbances
Define
Succession
The predictable changes to a community over time
Define
Primary succession
The establishment of a new community where there previously was none, and the predictable changes that happens to that community
Describe
Primary succession
Rocky area that lacks soil is inhabited by pioneer species
The pioneer species (plants) break down the terrain and build layers of soil
New plant species replace the pioneers, and simple animal species enter as well
Community changes continue until equilibrium occurs
Define
Secondary succession
Succession of an uninhabited area that already has established soil
Define
Climax community
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