Ch 40: Ecology Flashcards
Ecology
Study of interactions between organisms and the environment, Including Biotic (Living) and Abiotic (nonliving)
Biotic factors
plants, animals, dead trees, may include behaviors as well as interactions with other species
Abiotic Factors
Nonliving, chemical, and physical components, E.x air, water, soil, sunlight, temperature, and climate
Climate
the weather in some locations averaged over some long period of time.
2 Scales of climate
Macroclimate patterns, Microclimate
Macroclimate patterns
global, regional, local levels the changing angle of the sun over the year, bodies of water, and mountains exert seasonal, regional, and local effects on macroclimates
Microclimate
the small fine-scale variation, for example under a log or on a riverbank shaded by vegetation
Biomes
3 things
Major types of ecosystems that occupy very broad geographic regions
- The layering of vegetation in all biomes provides diverse habitats for animals
- Biomes are dynamic and usually exhibit extensive patchiness
- Similar characteristics can arise in distant biomes through convergent evolution
Two main types of Biomes
Aquatic and Terrestrial.
General Features of Terrestrial Biomes(3)
- named for major physical or climatic factors and for vegetation
- No sharp boundaries
- Vertical layering is an important feature of terrestrial biomes, and in a forest, it might consist of an upper canopy, low-tree layer, shrub understory, ground layer of herbaceous plants, forest floor, and root layer
- ecotone - area of intergraation
Disturbance and Terrestrial Biomes
- A disturbance is an event such as a storm, fire, or human activity that changes a community
- Fire suppression has changed the vegetation of the Great Plains
Aquatic Biomes(3)
1- The largest part of the biosphere (planet) – covers 75% of the surface
2- Two types – Freshwater and Marine
3- All Aquatic Biomes have Vertical stratification which forms unique layers
Photic Zone(aquatic)
enough light for photosynthesis to occur a (Aphotic –almost no light)
Benthic Zone(aquatic)
the bottom layer, composed of sand, inorganic matter, organic sediments called
detritus (dead)
Thermocline(aquatic)
As you go from top to bottom you have multiple layers of fast temperature changes
thermocline(aquatic)
separates the warm upper layer from the cold deeper water, in oceans and most lakes, a temperature boundary
turnover(aquatic)
Many lakes undergo a semiannual mixing of their waters, mixing oxygenated water from the surface with nutrient-rich water from the bottom
Two types standing bodies (lakes), and running bodies (rivers)(Freshwater Biomes)
Littoral Zone and Limnetic zone
Oligotrophic lakes(Freshwater Biomes)
deep lakes that are nutrient-poor and oxygen-rich contain little phytoplankton
Eutrophic lakes(Freshwater Biomes)
shallower, high nutrient content and lower oxygen levels high concentration of phytoplankton
current(Freshwater Biomes)
the unique physical features of Streams and rivers
What do flowing bodies of water have?(Freshwater Biomes)
Flowing bodies of water have vertical divisions from the headwaters to the mouth, If unpolluted they can be very productive
Estuaries (Freshwater Biomes)
where freshwater streams or rivers merge with the ocean
Intertidal zone(Marine Biomes)
where land meets the water, submerged and exposed by the twice-daily tides.
Neritic zone(Marine Biomes)
past intertidal zone shallow water over continental shelves
Pelagic biome(Marine Biomes)
the vast realm of open water
Coral reef(Marine Biomes)
created by cnidarians and their hard calcium carbonate shells. Support other corals, sponges, and algae. Among the most productive ecosystems on Earth.
Must define a population
a group of individuals of a single species living in the same general area
Population Ecology
Study of how biotic and abiotic factors influence a populations
4 factors that influence populations
- Density
- Distribution
- Size
- Age
Density
number of individuals per area (the unit of area can change), births→ immigration increases, deaths→emigration increases
Dispersion
a pattern of spacing among individuals within the boundaries of the populations.
3 types of dispersion
Clumped, Uniform, and Random
Demography
the study of vital statistics of a population and how they change over time. Birth and Death rates especially using survivorship curves
life table
age-specific summary of the survival pattern of a population, made by following cohorts
cohort
a group of individuals of the same age
survivorship curve
is a graphic way of representing the data in a life table, The survivorship curve for Belding’s ground squirrels shows a relatively constant death rate
Survivorship curves can be classified into three general types(name and define)
- Type I: low death rates during early and middle life and an increase in death rates among older age groups
- Type II: a constant death rate over the organism’s life span
- Type III: high death rates for the young and a lower death rate for survivors
reproductive table
or fertility schedule is an age-specific summary of the reproductive rates in a population, It describes the reproductive patterns of a population
The Exponential Model of Population Growth
- It is useful to study population growth in an idealized situation
- Idealized situations help us understand the capacity of species to increase and the conditions that may facilitate this growth
- Any species, regardless of its life history. Is capable of exponential growth if resources are abundant.
Exponential population growth(4)
is population increase under idealized conditions
- Under these conditions, the rate of increase is at its maximum, denoted as rmax
- The equation of exponential population growth is
- Exponential population growth results in a J-shaped curve
- The J-shaped curve of exponential growth characterizes some rebounding populations
The Logistic Model of Population Growth
- Exponential growth cannot be sustained for long in any population
- A more realistic population model limits growth by incorporating carrying capacity
- Carrying capacity (K) is the maximum population size the environment can support without habitat degradation
- Carrying capacity varies with the abundance of limiting resources
Life History
- Traits that affect an organism’s schedule of reproduction and survival.
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Three Variables
- How early in life does reproduction begin?
- How often does the organism reproduce?
- Some have one event (big-bang reproduction(semelparity)
- Some produce offspring in repeated events (iteroparity)
- How many offspring per reproductive event
- These traits are evolutionary outcomes, not conscious decisions by organisms
K-selection
life-history traits that are sensitive to population density and carrying capacity. (logistic model), Populations living close to the density imposed by the carrying capacity
r-selection
life-history traits maximize reproductive success (exponential model)
density-independent populations
birth rate and death rate do not change with population density
density-dependent populations
birth rates fall and death rates rise with population density
Competition
as the density of a population increases the competition for resources intensifies. Organisms compete for food, space, or essential nutrients
Territoriality
Available space for territories or nesting may be limited thus controlling the population
Disease
increasing densities allow for easier transmission of diseases.
Predation
As prey populations increase, predators may find the prey more easily
