Concepts in Ecology Flashcards
What is ecology?
The scientific study of the interactions between organisms and the environment to determine organisms’ distribution and abundance.
What are the different types of ecology?
- Organismal Ecology
- Population Ecology
- Community Ecology
- Ecosystem Ecology
- Landscape Ecology
- Global Ecology
What is Organismal Ecology?
Studies how an organism’s structure, physiology, and behaviour (in animals) meet environmental challenges
What is population ecology?
Analyzes factors that affect population size and how/why it changes over time.
What is community ecology?
Examines how interactions between species, such as predation and competition, affect community structure and organization.
What is ecosystem ecology?
Emphasizes energy flow and chemical cycling among various biotic and abiotic components of an ecosystem
What is the ecological hierarchy?
Individuals: individual organisms of a certain species
Population: group of individuals of the same species living in an area
Community: group of populations of different species in an area
Ecosystem: community of organisms as well as the abiotic factors they interact with.
What is a landscape/seascape?
Mosaic of connected ecosystems.
What is landscape ecology?
Focuses on the exchanges of energy, materials, and organisms across multiple ecosystems.
What is the biosphere?
Global ecosystem: sum of all the planet’s ecosystems and landscapes.
What is global ecology?
Examines the influence of energy and materials on organisms across the biosphere.
What is a biome?
Major life zones characterized by vegetation types (terrestrial) or by the physical environment (aquatic biomes)
What is the equation for population growth?
Change in population size = births + immigrants - deaths - emigrants
What are the different models that can predict population growth rate?
- exponential population growth
- logistic population growth
What is the exponential model of population growth?
Exponential growth model assumes idealized conditions, unlimited resources, constant birth and death rates, and no migration.
what is the mathematical prediction of exponential population growth?
dN/dt = rN
dN/dt: rate of change of population size
r: per capita rate of increase
N: population size
What is the formula to find the annual per capita rate of increase (r)?
r = b - m
r: per capita rate of increase
b: annual per capita birth rate
m: annual per capita mortality rate
What is the logistic population growth model?
Model that limits growth by incorporating carrying capacity and describes how a population grows more slowly as it nears its carrying capacity.
what is carrying capacity (K)?
maximum population size the environment can support.
What factors limit growth to a carrying capacity in a large population?
Competition, disease and predation
What is the mathematical prediction of population growth?
dN/dt = rN * (K-N)/K
dN/dt: rate of change of population size
r: per capita rate of increase
N: population size
K: carrying capacity
What is the life history of an organism? What are the three traits it includes?
Traits that affect an organism’s schedule of reproduction and survival. Includes:
- Age at which reproduction begins
- How often organism reproduces
- How many offspring produced during each reproductive cycle.
What are life history traits?
evolutionary outcomes reflected in development, physiology, and behaviour of an organism
What is the difference between iteroparity and semelparity
Semelparity: species reproduce once and die (big bang reproduction), favoured in highly variable environments
Iteroparity: species produces offspring repeatedly throughout its life, favoured in dependable environments
What are ecological trade offs?
An improvement in the status of number of offspring/resources for nurturing is necessarily associated with a decline in or loss the other.
What are the types of life history trade-offs?
r-selection/density-independent: selection for traits that maximize reproductive success in uncrowded environments.
K-selection/density-dependent: selection for traits that are sensitive to population density and favoured at high density
What is the difference between r-selected and K-selected species?
r-selected: small, fast-growing organisms that live in unstable environments and produce a large number of offspring
K-selected: large, slow-growing organisms that live in stable environments and produce only a few offspring that they can give a lot of care to
What are the structural features of communites?
- species richness
- biodiversity
- Keystone species
What are Dynamic features of communities?
- competition
- predation
- Herbivory
- Symbioses
What is the difference between structural and dynamic features of communities?
structural: the types and numbers of species present
dynamic: how populations interact with eachother
What is biodiversity?
Total number of species, their evenness, composition, and genetic diversity.
What is exploitative conservation/direct value of biodiversity?
Functions of individual species that serve humans directly (e.g. food/agriculture, medicine, energy, materials)
What is the difference between species richness and species evennness?
species richness: measure of the number of different types of species in an ecosystem
species evenness: measure of the relative abundance of each species
What are interspecific interactions?
Interactions between species in a community that may affect the survival and reproduction of each species. They are summarized as +, -, or 0. Includes competition, predation, herbivory, parasitism, mutualism, and commensalism.
What is interspecific competition?
-/- interaction that occurs when individuals of different species compete for a resource that limits their growth and survival
What are types of interspecific competition?
Exploitative: inderect interactions (resource usage)
Interference: direct interaction (prevent usage)
What does an organism allocate its energy to at varying levels of competition?
low competition: growth
moderate competition: growth and reproduction
high competition: growth, reproduction and survival
What is competitive exclusion?
Local elimination of the inferior competitor due to a reproductive advantage.
What is an ecological niche?
Specific set of biotic and abiotic resources that an organism uses in its environment to fit into the ecosystem.
What is the difference between a fundamental niche and a realized niche?
Fundamental: niche potentially occupied by that species, but varies due to competition.
Realized: portion of fundamental niche that the species actually occupies
What are the similarities and differences of weather and climate?
Similarities: highly variable, high impact on life, abiotic component of ecosystem
Differences: Weather refers to a specific time and place, climate refers to long term weather patterns on a local, regional or global scale
What determines Global climate pattens?
Determined largely by solar energy (causes temp variations which drive evaporation and circulation of air and water) and Earth’s movement in space (causing latitudinal variations in climate).
What does the angle at which sunlight hits the earth affect?
intensity and amount of heat and light per unit of surface area
How do global air circulation and precipitation patterns play major roles in determining climate patterns?
- Water evaporation + warm wet air masses in tropics release water and cause high precipitation
- Dry descending air masses create arid climates
- Air flowing close to earth’s surface creates predictable global wind patterns
- Cooling trade wins blow from east to west in tropics while prevailing westerlies blow from west to east in temperate zones.
What does elevation affect?
Temperature and Humidity
What are Chinooks?
Warm winds that rush down the east side of the Rocky Mountains. Warm Pacific air travels over the mountains, cooling and losing a lot of moisture
What are microclimates?
Essentially uniform local climate of a usually small site or habitat determined by fine-scale differences in temp, humidity, and light.
What is population density?
Structural feature of population that denote the number of individuals per unit area or volume.
What is the difference between crude density and ecological density?
Crude: total number of individuals per unit of the total space
Ecological: number of individuals per unit of the habitat space
What is dispersion?
Pattern of spacing among individuals within the boundaries of the population. Includes clumped, uniform, and random dispersion.
What is the difference between clumped, uniform and random dispersion?
Clumped: individuals aggregate in patches
Uniform: individuals are evenly distributed
Random: The position of each individual is independent of other individuals
What are the three hypothetical survivorship curves?
Type I: low mortality in youth, high mortality in old age
Type II: constant death rate over the organism’s life span
Type III: high mortality in youth and low mortality in survivors
What is resource partitioning?
Two or more similar species coexisting where each species only uses part of the available resources.
What is predation? What regulates predator and prey populations?
Exploitative +/- interaction between species in which a predator species kills and eats the prey species.
Predatory populations are regulated by food availability, Prey populations are regulated by predation.
What is Herbivory? What does it result in?
Exploitative +/- interaction in which an organisms eats parts of a plant or alga.
May result in promotion of plant growth, plant diversity, and mammal communities in grassland.
What is symbioses?
All interactions when individuals live in direct and intimate contact with on another; includes mutualism, parasitism, commensalism, altruism.
What is mutualism?
(+/+) interspecific interaction that includes obligate/facultative mutualism, trophic mutualism, defensive mutualism, and reproductive mutualism
What is the difference between obligate and facultative mutualism?
Obligate: One species cannot survive without the other
Facultative: both species can survive alone
What is trophic mutualism?
Both the engaged partners obtain nutrients and energy from each other in a complementary way, both the partners are specialized in such ways.
What are two examples of mutualism?
- Mycorrhizae: fungi absorb water + nutrients, plant gives fungi food
- Algae provide oxygen for developing salamander embryos, while embryos provide nutrients that facilitate growth of algae
What is defensive mutualism and an example?
One species receives protection against predators or parasites in exchange for offering shelter or food to its partner species. (e.g. aphid provides energy source for ants, ants protect aphids)
What is reproductive mutualism?
One species increases the reproductive success of the other species, while obtaining nutrients in return. (e.g. plant-pollinator relationship, animals eat fruit and spread seeds in droppings)
What is parasitism?
(+/-) symbiotic interaction where the parasite derives its nourishment from the host which results in negative impacts on host fitness (growth, survival, reproduction, increased mortality)
What is commensalism?
(+/0) Interaction between species that benefits one species and neither harms nor helps the other
What are two examples of commensalism?
- Clownfish get protection from predators from stinging anemone, having no effect on anemone
- Remora attaches itself to shark and save energy by remaining stationary and snacks on shark kills.
Why is commensalism difficult to confirm?
Any close association between species likely affects both species even if only slightly.
What is altruism ad an example?
Behaviours that increase the fitness of another individual, even to the point of potential detriment for themselves. May include reciprocal altruism (individuals sharing food with individuals whom they have received food)
What is trophic structure?
Feeding relationships between organisms in the community. Includes food chains (who eats whom) and food levels (branching food chain with complex trophic interactions)
What are the trophic levels from bottom to top?
Producers, Primary consumers, Secondary consumers, Tertiary consumers, Apex predators.
What is a keystone species?
Species that maintains the local biodiversity of ecosystem and has a disproportionately large effect on community structure, diversity and abundance, relative to its biomass/abundance.
What is the result of the removal of a keystone species?
- Reduced biodiversity and ecosystem degradation
- Surge in species population, potentially outcompeting and displacing other species (top-down trophic cascade)
What is an example of a keystone species?
Sea otters prey on sea urchins and prevent them from overpopulating the seafloor, devouring kelp forests that provide cover and food for many other marine animals.
What is a community disturbance?
Disturbance changes a community by removing organisms or changing resource availability (fire, flood, human activity).
Why is intermediate disturbance able to foster greater diversity than high or low disturbance?
Species that thrive at both early and late successional stages can coexist.
What do high and low level disturbance exclude?
High: slow growing species
Low: Dominant species exclude less competitive species
What are succession mechanisms?
Sequence of community and ecosystem changes after a disturbance.
How does energy flow through food webs?
Solar energy is harnessed and transformed into biomass and heat, openly flowing through the system.
How do nutrients flow through the food webs?
Nutrients are recycled in a closed system, where inputs, transformations and losses happen at any point.
What is the rule of thumb in the trophic pyramid?
Only about 10% of energy stored in organic matter in a given trophic level is converted to organic matter in the next trophic level.
What are detritivores?
Decomposers that get their energy from detritus (nonliving inorganic material); usually prokaryotes and fungi
What are the reservoirs of carbon?
Carbonate rocks: mostly inaccessible (64e6 Gt)
Atmospheric CO2: Biologically available for carbon fixation (548 Gt)
Dissolved CO2: biologically available (630 Gt)
Biomass: Biologically available (610 Gt)
