Midterm Flashcards
(218 cards)
1
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Ecology
A
The scientific study of interactions between organisms and their environment that determines their distribution and abundance.
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Evolution
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A change in gene frequencies within a population over time.
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Adaptation
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A characteristic of an organism that improves its ability to survive or reproduce
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Natural Selection
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The process by which individuals with certain traits tend to survive and reproduce at a higher rate than other individuals because of those traits.
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Population
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Group of individuals of a specie that live in the same area and interact with each other.
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Community
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An association of interacting populations of different species that live in the same area
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Biotic
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Living things in a natural system.
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Abiotic
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Physical, non-living components of a natural system
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Ecosystem
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The community and the physical environment (Biotic & abiotic)
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Landscape
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Areas that very substantially from one place to another and typically include more than one ecosystem
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Biosphere
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All living organisms on Earth plus the environments in which they live
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Producer
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Captures energy from an external source and uses it to produce food.
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Consumer
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Get energy by eating other organisms or their remains
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Net Primary Productivity (NPP)
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Energy captured by producers, minus the amount lost as heat in cellular respiration
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Ecological Maxims
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- Organisms interact & are interconnected 2. Everything goes somewhere 3. No pop can increase in size forever 4. Finite energy and resources result in tradeoffs 5. Populations evolve 6. Communities and ecosystems change over time 7. Spatial scale matters
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Ecological Hierarchy (bottom to top)
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Organism –> Population –> Community –> Ecosystem –> Landscape –> Biosphere
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Difference between movement of energy vs nutrients in an ecosystem
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Nutrients cycle but energy flows.
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Laboratory experiments
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Control large # of variables, easier to finance. Lack realism, useful for developing hypotheses.
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Large-scale field experiments
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Huge in scope & good for understanding large scale effects. Hard to control variable and expensive.
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Small-scale field (Mesocosm)
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act as an intermediate, we can manipulate the environment, control factors & variables. Lacks some of the realism from large-scale.
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Steps of Experimental Design
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- Assignments of treatments and control 2. Replication 3. Random assignment of treatments 4. Statistical Analyses
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Scientific Method
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The process is iterative & self-correcting. 1. Make observations & ask questions 2. Develop Hypotheses 3. Evaluate Hypotheses 4. Use results to modify hypotheses
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Biological indicator
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Something that will tell us about the environment. Amphibians are good biological indicators because skin is permeable, eggs lack a protective shell, and they live both on land and in water.
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Convergence
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Evolution of similar growth forms among distantly related species in response to similar selection pressures.
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Biome
Large-scale biological communities shaped by the physical environment, particularly climate. Biomes are categorized by dominant plant forms.
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Epiphyte
Don't have roots but grow from branches higher in trees.
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Desertification
Loss of plant cover and soil erosion as a result of unsustainable practices
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Permafrost
Soil that remains frozen year-round. Prevents drainage and results in saturated soils.
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Lotic
Moving water bodies
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Lentic
Still water bodies
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Benthic zone
Organisms that are bottom dwellers, live and feed on detritus & hyporheic zone.
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Detritus
Dead organic matter
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Hyporheic zone
The substratum below and adjacent to the stream. It's filled with pores and such that invertebrates can live in.
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Littoral zone
Near shore, where the photic zone reaches the bottom.
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Pelagic Zone
Open water, dominated by plankton. Not closely associated with the benthic part of a water body.
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Plankton
Small and microscopic organisms suspended in water.
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Phytoplankton
Are photosynthetic, restricted to the Photic Zone
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Zooplankton
Non-photosynthetic organisms
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Photic Zone
Where all the light can reach bottom. Extends to about 200m in depth.
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How are biomes defined / categorized
Upon dominant plant forms. Because plants occupy sites for a long time and are good indicators of the physical environment.
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Effect of Precipitation & Temp on Biome type
Precip & Temp act together to influence water availability and water loss by plants.
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Mountains mimic terrestrial biomes
Temperatures and precipitation change with elevation, resulting in zones similar to biomes.
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Climate envelope
The range of environmental conditions over which a species occurs / lives
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Actual distribution
Related to other factors such as disturbance and competition
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Potential distribution
The area matching the environmental conditions over which a species occurs
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Stress
Environmental change results in decreased rates of physiological processes, lowering the potential for survival, growth, or reproduction.
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Acclimatization
Adjusting to stress through behavior or physiology. Usually a short-term, reversible process.
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Trade-off
Processes require energy and resources, investment in such processes comes at the expense of maintaining others.
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Denatured enzyme
Enzyme whose function has been lost.
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Isozyme
Variable forms of enzymes with different temperature optima that allow acclimatization to changing conditions.
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Ectotherm
Regulate body temperature through energy exchange with the external environment.
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Endotherm
Rely primarily on internal heat generation, mostly birds and mammals.
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Freezing avoidance
Seasonal migration to lower latitudes or to microsites that are above freezing (burrows)
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Freezing tolerance
Minimizing damage associated with ice formation in cells.
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Thermoneutral Zone
The range of environmental temperature over which a constant basal metabolic rate can be maintained
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Lower critical temperature
When heat loss is greater than metabolic production; body temp drops, and metabolic heat generation increases. This is at the lower end of the thermoneutral zone.
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Dormancy
A state in which little or no metabolic activity occurs.
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Torpor
A state of dormancy in cold climates where body temperature and basal metabolic rates are low to conserve energy (Hibernation)
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Evaporative heat loss
Sweating, panting and licking of the body are methods
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Desiccation tolerance
Reduce surface area-to-volume ratio to minimize evaporative heat loss
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Conduction
Transfer of energy from warmer to cooler molecules
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Convection
Heat energy is carried by moving water or air related to speed of air flow
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Evapotranspiration
Water is drawn from the bottom of plants out through the leaves
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Stomates
Specialized guard cells surrounding leaf openings called stomates
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Pubescence
Hairs on leaf surfaces that reflect solar energy. These hairs also reduce conductive heat loss.
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Boundary layer
A zone of turbulent flow due to friction, next to the leaf surface. Boundary layers increase with leaf size and surface roughness. Greater boundary layer = less conductive heat loss.
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Autotroph
Assimilate radiant energy from sunlight, or from inorganic compounds
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Photosynthesis
Sunlight provides the energy to take up CO2 and synthesize organic compounds
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Chemosynthesis
Energy from inorganic compounds is used to produce carbohydrates
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Heterotroph
Obtain energy by consuming organic compounds from other organisms (autotrophs) or non-living organic matter
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Predator
Capture and consume live prey animals
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Herbivore
Eat plant matter, often not killing the organism.
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Holoparasite
Plants that have no photosynthetic pigments and get their energy from other plants (heterotrophs)
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Hemiparasite
Is photosynthetic yet obtains nutrients, water, and some of its energy from the host plant.
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Light reaction
Light is harvested and used to split water & provide electrons to make ATP & NADPH
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Dark Reaction
CO2 is fixed in the Calvin cycle, and carbohydrates are synthesized
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Light compensation point
Where CO2 uptake is balanced by CO2 loss by respiration
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Photorespiration
Oxygenase reaction that works in opposite to photosynthesis. It takes up O2 and breaks down carbon compounds to release CO2.
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C4 Photosynthesis
Reduces photorespiration. Has physically separated the CO2 uptake and Calvin cycle. CO2 is taken up by PEPcase (high affinity). C4 requires more ATP, transpiration losses are minimized because CO2 uptake can continue with closed stomates.
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CAM Photosynthesis
Ideal for minimizing water loss. CO2 uptake and the calvin cycle are separated temporally --> Open stomates at night, close them during the day.
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Light Saturation Point
Rate of photosynthesis no longer increases as light intensity does.
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Light Compensation Point
Net photosynthetic CO2 uptake rate is 0.
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Mutation
Source of variations in species. The formation of new alleles is critical to evolution.
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Genotype
The genetic make up of an organism
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Phenotype
Observable characteristics determined by the genotype
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Directional Selection
Individuals at one phenotypic extreme are favored over others
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Stabilizing Selection
Individuals with an intermediate phenotype are favored
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Disruptive selection
Individuals at both phenotypic extremes are favored --> Can lead to diversification & speciation
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Genetic drift
Occurs when chance events determine which alleles are passed to the next generation
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Fixation
When an allele is the only version seen in a population it is fixed, it has gone to fixation.
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Gene flow
Alleles move between populations via movement of individuals or gametes. Populations become more similar & new alleles can be introduced into a population.
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Adaptive Evolution
The favoring of adaptations through natural selection
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Cline
Patterns of change in a characteristic over a geographic region
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Species
Groups of organisms whose members have similar characteristics and can interbreed.
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Speciation
The process by which one species split into two or more species
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Habitat fragmentation
Creates isolated patches that can amplify the effects of evolutionary processes.
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Life History
Major events in an animals life including age & size at sexual maturity, amount and timing of reproduction, and survival & mortality rates.
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Life History Strategy
The overall pattern in the timing and nature of life history events. Determined genetically and through natural selection.
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Fitness
The success of genetic contributions to future generations
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Phenotypic Plasticity
One genotype that can produce different phenotypes under different environmental conditions. It may result in a continuous range of sizes; or discrete types called morphs.
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Polyphenism
A single genotype produces several distinct morphs
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Allometry
Differential growth of body parts that results in differences in shape or proportion with size.
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Asexual reproduction
Simple cell division (binary fission), all prokaryotes & some eukaryotes.
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Direct development
Fertilized egg passes into a juvenile without a larval stage
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Metamorphosis
Abrupt transition in form between the larval and juvenile stages
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Complex life cycle
Have at least two stages with different body forms and that live in different habitats.
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Semelparous
Species reproduce only once
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Iteroparous
Species can reproduce multiple times
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r, and r-selection
R is the intrinsic rate of increase of a population. R selection: for high population growth rates; an advantage in newly disturbed habitats and uncrowded condition, produce a lot of offspring early on without much parental investment.
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K, and K-selection
K is the carrying capacity for a population. K selection: for slower growth rates in populations that are at or near K: an advantage in crowded conditions where efficient reproduction is favored. Long-lived and invest heavily in each offspring.
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Stress
Any abiotic factor that limits growth.
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Disturbance
Any process that destroys plant biomass
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Competitive plants
Superior ability to acquire resources and have a selective advantage (low stress, low disturbance)
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Stress-tolerant plants
Have phenotypic plasticity, slow rates of water & nutrient use --> Not palatable to herbivores. (High stress, low disturbance)
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Ruderal plants
Short life span & rapid growth rates. Seeds can survive a long time. Good in low stress & high disturbance.
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Propagule
A seed or egg
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Dormancy
State of suspended growth and development in which an organism can survive unfavorable conditions.
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Niche
The physical and biological conditions that an organism needs to grow, survive, and reproduce
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Niche shift
Movement in one niche to another as a result of gradual morphological change
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Paedomorphic
An organism that retains juvenile morphology and habitat
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Behavioural Ecology
Evolutionary basis for behaviors
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Optimal Foraging Theory
Animals will maximize the amount of energy gained per unit of feeding involved
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Marginal value theorem
An animal should stay in a patch until the rate of energy gain has declined to match the average rate for the whole habitat (giving up time)
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Handicap Hypothesis
A male who can support such a costly and unwieldy ornament is likely to be a vigorous individual whose overall genetic quality is high
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Sexy son hypothesis
Females receive indirect benefits through her sons, who will themselves be attractive to females and produce many offspring.
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Monogamy
Being partners with one individual at a time
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Polygyny
One male to many females
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Dilution Effect
As number of individuals in a group increases, the chance of being the one attacked by a predator decreases.
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Proximate causes of behavior
Regarding how the behavior occurs (immediate)
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Ultimate causes of behavior
Why the behavior occurs as well the evolutionary & historical reasons.
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Profitability calculation
Profitability = Energy (from food) / Time (spent obtaining the food)
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Direct & Indirect Benefits
The ones that partners receive from the other whereas indirect benefits are the good genes found in a mate that could be passed to offspring.
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Distribution
Geographic area where individuals of a species occur
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Abundance
Number of individuals in a given area, reported in size (# of indiv) or in density (# of indiv in unit of square area)
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Budding
A small part may come off of a larger part and live independently
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Apomixis
A single individual may produce viable propagules on their own
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Horizontal spread
A vegetative structure may come off and produce buds
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Genet
A single genetic individuals
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Ramet
Physiologically independent members of a genet
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Disturbance
Events that kill or damage some individuals, creating opportunities for other individuals to grow and reproduce.
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Dispersal limitation
Prevents species from reaching areas of suitable habitat
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Geographic range
The entire geographic region over which a species is found, includes areas occupied during all life stages.
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Dispersion
Spatial arrangement of individuals within a population
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Cooperative breeding
Young birds postpone breeding to help their parents raise more offspring
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Relative population size
Number of individuals in one time period or place relative to the number in another. Estimates are based on data presumed to be related to absolute population size.
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Quadrat
An example of an area-based count. Sampling areas of a specific size. Individuals are counted in several quadrats; the counts are averaged to estimate population size. Determine the avg # in each quadrant then divide by quadrant size in meters squared.
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Line transect
An observer travels along a line and counts individuals and their distance from the line
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Ecological Niche
Physical and biological conditions that a species needs to grow, survive, and reproduce.
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Niche model
Predicts a species' distribution based on conditions at locations the species is known to occupy.
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Area based counts
Used most often to estimate abundance of immobile organisms
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Distance methods
Distances of individuals from a line or point are converted into estimates of abundance
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Mark recapture studies
Used for mobile organisms, a subset of individuals is captured and marked then released. Later, individuals are captured again, and the ratio of marked to unmarked individuals is used to estimate population size. M (marked) x C (captured) / R (marked and recaptured)
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Habitat Rule
The environmental conditions where an organism is most likely to be found.
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Life table
A summary of how survival and reproductive rates vary with age
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Survival Rate
Probability of surviving from age x to age x + 1
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Survivorship
Proportion of individuals that survive from birth to age X
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Fecundity
Number of offspring produced by a female at age X
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Type 1 Survivorship curve
Most individuals survive to old age
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Type 2 Survivorship curve
Chance of survival remains constant throughout the lifetime
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Type 3 Survivorship curve
Very high death rates for young, those who reach adulthood survive well
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Age structure
The proportion of the population in each age class
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Geometric Growth
If a population reproduces in synchrony at discrete time periods and growth rate doesn't change. Pop increases by a constant proportion.
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Geometric growth rate
Growth rate is N t+1 = Lambda (constant rate on increase) X Nt
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Exponential Growth
Individuals reproduce continuously and generations can overlap.
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Exponential Population Growth Rate
dN/dT(rate of change in pop size at each instant in time) = r(exponential pop growth rate)N
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Intrinsic rate of population increase
Aka exponential population growth rate = r
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Population regulation
Density- dependent factors cause population to increase when density is low and decrease when density is high. Density-independent factors (temp, precip, catastrophes) can have a large impact on population size but do not regulate it.
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Logistic Growth
Population increases rapidly, then stabilizes at the carrying capacity.
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Carrying Capacity
Maximum population size that can be supported indefinitely by the environment.
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Logistic Growth Rate
Equation assumes that r declines as N increases: dN/dt = rN(1-N/K), K = carrying capacity
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Various Growth Rates
- Lambda < 1 or exponential < 0 = negative growth
- Lambda = 1 or exponential = 0 we have constant pop size
- Lambda > 1 or exponential > 0 we see pop growth
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Population Dynamics
The ways in which populations change in abundance over time:
| Nt+1 = Nt + B(Births) - D(Deaths) + I(immigrants) - E(emigrants)
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Jump Dispersal
Colonize new regions by long-distance events
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Population Fluctuations
Fluctuations can be deviations from a growth pattern. These could reflect changes in environmental factors or predator abundance.
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Population Outbreak
Number of individuals increases rapidly
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Population Cycles
Populations have alternating periods of high and low abundance at regular intervals
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Delayed Density Dependence
Delays in the effect that density has on population size. Can cause populations to fluctuate in size. E.g the number of individuals born in a given time period is influenced by population densities from several time period ago
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Stable limit population cycyle
We see logistic growth, over shoot then undershoot and this cycle continues with the magnitude of miss being maintainted
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Damped oscillation population cycle
Logistic growth, then overshoot, undershoot, overshoot (not by as much), etc --> Magnitude of miss decreases with each oscillation
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Demographic stochasticity
Chance events affect the survival and reproduction of individuals
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Allee effects
At low densities, individuals have difficulty finding mates, so growth rate decreases as population density decreases. Allee effects can reduce small population size even further.
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Environmental Stochasticity
Change in average birth or death rates from year to year because of random changes in environmental conditions
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Natural Catastrophe
Can eliminate or reduce even large populations, and play a role in extinctions
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Metapopulation
A set of spatially isolated populations linked by dispersal of individuals or gametes. Characterized by repeated extinctions and colonization's of the small individual populations, but the metapopulation persists.
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Isolation by distance
When patches are too far apart
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Patch Size
Small patches may be hard to find and have high extinction rates
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Rescue effect
High rates of immigration that protect a population from extinction
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Eutrophication
High numbers of nutrients in the water allowing for an increase in phytoplankton, decreasing water clarity & oxygen concentrations. Low O2 = massive fish die off
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Bottom-up control
Targets bottom of the food chain
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Top-down control
Top predators control the abundance of populations
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Competition
An interaction between individuals in which each is harmed by their shared use of a limiting resource
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Interspecific
Interaction between two species in which each is harmed when they both use the same limiting resource
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Intraspecific
Between individuals of a single species
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Resource
Features of the environment required for growth, survival, or reproduction, and which can be consumed to the point of depletion
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Physical Factor
Species are also influenced by physical factors (abiotic) that are not consumed such as temperature, pH, salinity. These are not considered to be resources.
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Exploitation competition
Species compete indirectly: Individuals reduce the availability of a resource as they use it
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Interference competition
Species compete directly for access to a resource; this may involve antagonistic actions
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Allelopathy
Plants of one species release toxins that harm other species
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Amensalism
Individuals of one species harmed, the other is not.
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Competitive exclusion principle
If the ecological niches of competing species are very similar, the superior competitor may drive the other species to extinction --> Two species that use a limiting resource in the same way cannot coexist.
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Resource Partitioning
Species using a limited resource in different ways.
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Competition Coefficients
Constants that describe effect of one species on the other (alpha & beta)
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Competitive Reversal
The inferior competitor in one habitat becomes the superior competitor in another habitat
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Character Displacement
Natural selection can influence the morphology of competing species and result in the phenotypes of competing species become more different over time
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Lotka-Volterra competition model
A model to predice the outcome of competition. dN1/dt = r1N1(1-(N1 + alphsN2)/K1) where N1 is pop density of species 1, r1 is intrinsic rate of increase of species 1, K1 is carrying capacity of species 1. Coexistence occurs when alpha < K1/k2 < 1/beta
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Herbivore
Eats tissues of living plants or algae
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Predator
Kills and eats other organisms, referred to as prey
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Parasite
Lives in or on another organism, feeding on parts of it. Typically do not kill the host.
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Parasitoid
Insects that lay an egg on or in another insect host. After hatching, larvae remain in the host, which they eat and often kill.
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Sit-and-wait Predator
Remaining in one place and attacking prey that move within striking distance
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Exploitative interaction
A relationship in which one organism benefits by feeding on, and directly harming another.
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Aposematic Coloration
Bright coloration that serves as a warning to inform predators of organisms that have toxins
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Crypsis
The prey is camouflaged, or resembles its background.
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Mimicry
The prey resembles another organism that is toxic or very fierce
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Masting
The production of huge numbers of seeds in some years and very few in other years
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Compensation & compensatory growth
Removal of plant tissue stimulates new growth at apical sites.
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Induced defenses
Produced in response to herbivore attack.
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Secondary compounds
Toxic chemicals to reduce herbivory
