Ecology Study Set - Biology Exam 4

Ecology

The scientific study between organisms and their environments

Population

A group of the same species living in a defined area

Community

A group of differing populations living in a specified area

Ecosystem

The community of organisms in an area and the physical factors they interact with

Landscape Ecology

How spatial patterns and ecological processes interact across different scales, shaping ecosystems, biodiversity, and environmental dynamics

Biosphere

The sum of all the planet’s ecosystems and landscapes

Climate

The long term (with a minimum of 30 years of study) prevailing weather conditions at a given place

Global Air Circulation

Hot air rises and cool air sinks - at the equator, air and water masses are heated, sent towards the poles, cooled, and circulated back down

Reasoning for Air Flow Towards Poles

Since the planet is roughly spherical, different areas spin at different speeds. The equator, which has the largest circumference, moves the fastest, whereas regions closer to the poles move more slowly. This difference in rotational speed affects how air moves across the planet. As a result, air is deflected away from the equator and generally flows toward the north and south poles, shaping our weather and climate systems

Seasonality

Depicted by the earth’s tilt on its axis and movement around the sun (when it is summer in the northern hemisphere, it is winter in the southern hemisphere)

Cause of Wind

Water and air obtain different specific heat temperatures - during the day the air is warmer than water. This causes the air over the land to expand and rise. At the same time, the heavier/cooler air that rested above the hot air sinks back down (rapidly) and creates breezes

The Rain Shadow Effect

Moisture filled air is forced up over a mountain from the ocean. It is cooled and releases moisture - producing rain fall on the windward side. The air eventually falls back down on the leeward side

Vegetation Climate

Plants transpire and return water to the atmosphere - this act lowers temperatures and can induce precipitation

Abiotic Factors

Small scale differences in temperature, precipitation, sunlight, and wind

Biotic Factors

Living factors, or other organisms that are components of an individual’s environment

Microclimates

Localized patterns in landscape change via shade casting, alterations in soil evaporation, or changing wind patterns

Terrestrial Biomes

Major life zones characterized by vegetation (determining average temperature and precipitation of an area can lead to identification of this)

Tropical Forest

Lush vegetation, little variation in temperature (around 25 degrees C), consistent rainfall, and incredible biodiversity of plants and animals

Desert

Low and highly variable precipitation, low and scattered vegetation adapted to arid conditions (fluctuates between 10 - 25 degrees C)

Savanna

Long dry seasons followed by seasonal rainfall, scattered trees among grasses, larger herbivores and many insects

Chaparral

Rainy winters and dry summers, significant plant diversity with a majority of low shrubby plants, and browsing animals are common (like deer)

Temperate Grassland

Seasonal precipitation with dry, cold winters and wet, hot summers, many grasses, periodic drought and fire, large grazing animals, very fertile soils make them prime for agriculture

Northern Coniferous Forest

Largest terrestrial biome on earth locate only within the northern hemisphere - dominated by cone-bearing trees such as spruce, pines, figs, or heavily logged trees

Population Density

Number of individuals per unit area or volume

Population Dispersal

Patterns of spacing of individuals within the population boundary

Major Patterns of Dispersion

1. Clumped: resource availability and social interaction

2. Uniform: competition for resources and territoriality

3. Random: resource abundance and seed dispersal

Population Increase and Decrease Factors

Births and immigration lead to influx, while deaths and immigration lead to deflux - both influenced by competition, resource availability, habitats, etc.

Demographics

The study of vital population statistics and how they vary overtime

Life Tables

Often representing a cohort (a group of individuals of the same age that are followed until they are dead), these summarize survival and reproductive rates of individuals within a specific age group

Survivorship Type I Curve

Represents very little die off at early age - most deaths occur at later ages (ie. elephants and humans)

Survivorship Type II Curve

Obtaining 50/50 chance of either survival or death at any point of one’s life (ie. squirrels)

Survivorship Type III Curve

High mortality rate when individuals are young. Those that do survive will continue to live and see much older ages

Reproductive Rates

Focusing on females given their reproductive output statistics - high output does not guarantee high rates unless conditions for adequate growth and survival prevail

Exponential Growth

When resources are most plentiful and populations increase by a constant proportion at each instant in time

Logistic Growth

Increase in growth with an eventual flattening as the population approaches a point where resources can no longer sustain its growth

Carrying Capacity

The maximum population size that a particular environment can sustain

Density Dependance/Equilibrium Density

All organisms depend on their density given that enough individuals are needed to reproduce, but not to the point where resources are limited

Density Dependent Mechanisms

1. Competition: as population size increases, competition for resources will as well

2. Territoriality: trying to maintain dominance over a certain area - can lead to conflict and death

3. Disease: if transmission rates of disease increase as populations become more crowded, then its effect is dependent

Ecological Footprint

The summary of the aggregated resources required to sustain humans (can be heavily based on overall resource consumption)

Competition

The result of two different species using a resource that limits the survival and reproduction of both individuals

Ecological Niche

Inclusion of all environmental factors that influence growth, survival, and reproduction of a species

Fundamental Niche

The physical abiotic conditions species live under - in the absence of interactions with others

Realized Niche

The portion that occupies interaction amongst other species such as competition, predation, disease, and parasitism

Competitive Exclusion

Two different species occupy identical niches and are competing for the same limiting resource - they cannot coexist indefinitely, and ultimately one species will rule out the other

Resource Partitioning

The differentiation of niches that enables different species to coexist within a community

Exploitation

A species utilizing another species where one benefits and the other is harmed - predation, herbivory, and parasitism (these relationships can drive out certain organisms and lead to influxes of growth in others)

Endoparasites

Parasites that live within their host organisms

Ectoparasites

Parasites that live on the exterior of their hosts

Mutualism

An organismal relationship where both species benefit (mycorhizzal fungi on trees: fungi receive photosynthetic products while the tree gains a more extensive root system for nutrient and water uptake)

Commensalism

An relationship that benefits one of the interacting species, but neither harms nor benefits the other

Species Diversity

The variation of different organisms that make up a community (more diverse communities are more likely to withstand environmental stresses)

Species Richness

Component of species diversity that depicts the number of different species found within a community

Relative Abundance

Component of species diversity that depicts the percentage of individuals belonging to a certain species within a community

Trophic Structure

Describes feeding relationships between organisms in a community (the base of the food chain primary producers: plants and autotrophs)

Primary Consumer

The organisms that injest primary producers

Secondary Consumer

The organisms that injest primary consumers (tertiary and quaternary consumers follow same pattern up the chain)

Foundation Species

Things large in size and high in abundance - trees, desert shrubs, kelp, or coral

Keystone Species

Species that are not in abundance in a community, but their presence improves community structure (cannot be identified until it has been removed from a community and induces drastic changes) - (ie. sea otters being removed from the California coast and sea urchins began to overpopulate)

Ecological Engineers

Significantly alter ecosystems and provide more complex habitat (ie. beavers building damns, and alligator trails/holes serving as refuge for birds and fish)

Disturbance

Any event that changes a community by removing organisms or altering their availability

Ecological Succession

Recovery from a large scale disturbance where the disturbed area is recolonized by a variety of species

Primary Succession

The ecological process where life begins in a barren and uninhabited area

Secondary Succession

The regrowth of an ecosystem following disaster that has not been completely wiped of all existing soil

Genetic Diversity

Genetic variation within a population and between populations

Ecosystem Diversity

Maintaining a variety of ecosystems on earth

Ecosystem Services

The services that natural ecosystems provide to humans

Provisioning

Products obtained from an ecosystem like food, water, or medicines (ie. honey produced by bees)

Regulating

Benefits obtained from the regulation of ecosystems like flood prevention, climate control, and erosion control (ie. mangrove forests with trees that thrive in saline water and soils - prevents coastal erosion and reduces impacts of storm surges)

Supporting

Services necessary for the production of all other ecosystems like nutrient cycling (ie. microorganisms in soil that enhance root growth and nutrient uptake)

Cultural

Non-material benefits obtained from ecosystems like educational, recreational, and spiritual

Nutrient Enrichment

A result of growing more food on land in shorter periods of time. This results in fertilizer run off into local waterways that eventually get dumped in larger bodies of water. Such accumulation depletes oxygen levels in water and makes it impossible to sustain life.

Environmental Toxins

Byproducts of human activity released into the atmosphere, waterways, animals, etc.

Greenhouse Gasses

Gases that can absorb yet also retain and emit solar energy, ultimately leading to an increase in atmospheric temperature

Ozone Layer

A layer of three oxygens that blocks harmful UV radiation from the sun

Ozone Layer Depletion

Caused by a man-made chemical being released into the air called chloroflourocarbon when oxygens bond to the CFC’s instead of each other and halt production

Introduced Species

Humans either accidentally or intentionally transporting species to a new location where they exhibit zero competition for resources and obtain the ability to dismantle resources and prey on native species

Overharvesting

Humans over consuming products leading to both loss of species and harmful waste

Global Change

Alteration in climate conditions, atmospheric chemistry, and ecological conditions that make earth’s capacity to sustain life unattainable

2 Approaches to Conserving Populations

1. Focus on small populations

2. Focus on declining populations to prevent them from becoming small

Minimal Viable Population Size

The minimum a population size can be at to sustain its numbers - examine the size of a small population as it begins to ream the effects of the population vortex

Effective Population Size

Examines the breeding potential within a population

Weighing Conflicting Demands

Process used by scientists when examining species to take into account the costs and benefits saving a certain species holds

Biodiversity Hot Spots

Relatively small areas around the globe with rich species diversity (protecting these spots ensures more species are cared for)

Natural Reserves

Islands of biodiversity in overall areas of altered habitat

Zoned Reserves

Extensive regions that are undisturbed surrounded by human activity

Urban Ecology

Looks at organisms and their environment in an urban setting

Aquatic Biomes

Biomes characterized by the amount of light penetration and nutrient availability

Photic Zone

Region of water where light levels are sufficient for photosynthesis

Aphotic Zone

Region of water where light levels are insufficient enough to carry out photosynthesis

Pelagic Zone

Region of water that is not considered near the shoreline (open water)

Benthic Zone

Region compromising the bottom of a body of water - includes sediments

Lakes

Standing bodies of freshwater of varying sizes - may be oligotrophic: oxygen rich and nutrient poor, or eutrophic: oxygen poor and nutrient rich

Wetlands

Flooded with water part of the time, supports plants that are adapted to water-logged soils, acts as biological filters for water run-off, important for flood prevention, one of the most productive biomes on Earth, home to diverse communities of organisms

Streams and Rivers

Moving water of varying velocities, great capacity to carve out the landscape and deposit materials further down river, headwater streams are often narrow with a rocky bottom, as the river progresses it grows in width and the amount of sediment

Estuaries

A transition zone between river and sea, brackish often salty inflow from the ocean, very nutrient-rich (salt marshes are an example), crucial for fish breeding and waterfowl feeding areas

Intertidal Zone

Submerged twice daily by tides, often brutally hot or buffeted by waves, variation in temperature and salinity

Ocean Pelagic Zone

Open ocean zone susceptible to ocean currents, distinct photic and aphotic zones - covers 70% of the Earth's surface

Coral Reefs

Formed from calcium carbonate skeletons of corals, incredibly biodiverse but threatened due to their narrow range of temperature and pH tolerance

Marine benthic Zone

Sea floor with many sessile organisms, typically aphotic

Temperate Broadleaf Forest

Moderate climates and rainfall, dominant species are the deciduous trees, heavily logged and settled but through conservation efforts are returning to their original range