Final Exam/Ecology Exam Flashcards
What is Ecology?
The scientific study of the interactions between organisms and their environment.
Abiotic Component
Nonliving chemical and physical factors such as temperature, light, water, minerals, air.
Biotic Component
Living factors, all the other organisms that are part of an individual’s environment.
Organismal Ecology
The evolutionary adaptations that enable individual organisms to meet the challenges of their abiotic environments.
Population Ecology
Population- A group of individuals of the same species living.
Community Ecology
Community- All the organisms that inhabit a particular area, how interactions between sp., such as predation, competition, and symbiosis, affect community structure and organization.
Ecosystem Ecology
Ecosystem- All the abiotic factors in addition to the community of species in a certain area. Energy flow and the cycling of chemicals among the various biotic and abiotic factors.
Biosphere
Global Ecosystem-Sum of all ecosystems. Includes the atmosphere to an altitude of several kilometers, the land down to the water-bearing rocks about 1500m deep, lakes and streams, caves, oceans to a depth of several kilometers.
Types of Ecology?
Organismal Ecology Population Ecology Community Ecology Ecosystem Ecology Biosphere
Sunlight
Aquatic Environment: Distribution of algae(Sunlight only goes down to certain depths in the sea.)
Land: In forests, shading by trees causes competition for light at ground levels.
Water
Aquatic Environment: Water Balance
Land: Drying out or dehydration, waxy coat on leaves
Mammals: Layer of dead outer skin with a waterproofing protein; kidneys excrete urea with minimal water loss.
Temperature
Affects metabolism
At temperature of 50 C(122 F) enzymes are denatured
Mammals and birds: warm-blooded, stay active over wider temperature ranges.
Wind
Causes evaporative cooling in summer
Bacteria, Protista, Insects: Depend on nutrients blown by the wind
Plants: Pollen and seeds dispersed by the wind; affects the pattern of plant growth.
Rocks & Soil
Physical structure and chemical composition of rocks and soil determine the distribution of plants, and animals that feed on plants.
The composition of underlying rocks affects water chemistry in rivers and streams.
Periodic Disturbances
Fires, hurricanes, tornadoes, volcanic activity can destroy biological communities.
Recolonization post-diaster/disturbance leads to changes in the community structure.
Abiotic Factors
Sunlight Water Tempature Winds Rocks & Soil Periodic Disturbances(Natural Disasters)
Thermoregulation
Contraction of blood vessels in the skin; contraction of muscles attached to hair causes goose bumps.
Acclimation
Longer term physiological response; related to the range of conditions that the species naturally experiences. Species living in warm climates cannot acclimate to the extreme cold.
Anatomical Responses
Seen more in plants than animals, trees show “flagging”.
Behavioral Responses
Reptiles move between sun and shade; birds migrate.
Physiological Responses
Thermoregulation
Acclimation
Anatomical Responses
Behavioral Responses
Population Ecology(Focuses On?)
- Population size- # of individuals
- Growth rate- rate of change in population size
- Density- # of individuals/ unit area
- Structure- relative #s of individuals of different ages, ethnicity, etc.
Population- Group of individuals of the same sp. living in a given area at a given time.
Population Density Measurement
- Count total # of individuals/area
- Sampling technique-
a. # of organisms in a given area:
larger than the # of samples and sample size, greater the accuracy
b. Indirect indications: # of nests or burrows
c. Mark-recapture method:
Place traps
Mark captured animals- tag/collar/spot
Release
Trap
Capture marked and unmarked animals
Estimate total # of individuals
Patterns of Dispersion
The way individuals are spaced within the population’s geographic range.
- Clumped patterns: Aggregates; due to the unequal distribution of resources
- Uniform pattern: Due to interactions among individuals
- Random: Absence of strong attraction/repulsion among individuals; rare
Exponential Growth Model
This is the rate of expansion under ideal, unregulated conditions. The population multiplies by a constant factor during a constant time. The rate at which the population grows depends on the number of individuals already in the population.
Logistic Growth Models
After exponential growth for a while, one or more environmental factors limit growth- population limiting factor.
Carrying Capacity
The number of individuals in a population that the environment can maintain with no net increase or decrease. Population growth=0.
Population Growth Models
Exponential Growth Model
Logistic Growth Model
Density-Dependent Factors
Population limiting factors whose effects intensify as the population increases in density(ex. food supply, accumulation of waste products.)
Density Independent Factors
Population limiting factors whose intensity is unrelated to population density, ex. weather change, such as frost .
Population Cycles
Some species have regular boom and bust cycles caused by predation, food supply constraints, reduced fertility due to stress from crowding.
Methods of Regulation of Population Growth
Density-Dependent Factors
Density Independent Factors
Population Cycles
Diversity
The variety of different kinds of organisms that make up the community.
Species Richness
Total # of different species in the community.
b. Relative abundance of the different species.
Prevalent Form of Vegetation
One of the Key Properties of Communities
Stability
Ability to resist change and return to original species composition after a disturbance. Depends on type of community and nature of the disturbance.
Trophic Structure
Feeding relationships among the various species
Interspecific Interactions: Interactions between species.
1. Competition
2. Predation
3. Symbiosis
Competition
As population density increases and nears carrying capacity,individuals compete for limiting resources such as food.
Gauss-Competitive Exchange Principle
Niche
The sum total of a species use of the biotic and abiotic resources in its environment is called the species niche.
Parts of niche include temperature range, size of trees, time of the day is active, size and type of insects it eats.
Resource Partitioning
The differentiation of niches that enables similar species to co-exist in a community. As a result of competition, one sp. may become extinct or one may evolve to use a different set of resources.
Predation
Predators- Acute senses such as claws, teeth, fangs, stingers or poison, heat sensing organs(rattlesnake)
Predation Defenses
Plant Defenses- Spines/thorns, chemical toxins
Animal Defenses- Hiding, escaping, defending, alarm calls, distraction displays, camo, cryptic coloration, chemical toxins, mimicry.
Effects Of Predation
When certain species are killed off by predators, it hurts the ecosystem.
Parasitism
One organism benefits, other is harmed.
Example:
Internal parasite-tapeworms, protozoa
External parasite- mosquitos suck blood, Aphids suck sap
Mutualism
Both organisms benefitted
Mycorrhizae-root-fungus association
Lichens-fungus-algae association
What is Ecological Succession?
The process of community change.
Primary Succession
When a community arises in a virtually lifeless area with no soil.
Takes hundreds or thousands of years
Autotrophic microorganisms, moss, lichens, grasses, shrubs, trees
Secondary Succession
Community destroyed but soil is intact.
Energy Flow
Passage of energy through the components of the ecosystem.
Chemical Cycling
The use and reuse of chemical elements such as carbon and nitrogen within the ecosystem.
Biomes
Major types of ecosystems that cover large geographic areas.
Tropical Rainforest
Rainfall
Vertical Stratification
Savanna
Grasslands with scattered trees
Large herbivores and predators
Insects- especially ants and termites
Desert
Sparse rainfall
Cacti- water saving adaptations- spines, poisons
Chaparral
Mid-altitude coastal areas with mild rainy winters and long, hot, dry summers
Dense evergreen shrubs
Temperate Grassland
Prairies of Central North America
Seasonal drought, occasional fires, grazing by large animals
Temperate Deciduous Forest
Deciduous trees
Animals hibernate in winter, trees drop leaves before winter
Coniferous Forest
Cone-bearing evergreen trees such as pine, spruce, fir and hemlock
Tundra
Permafrost(Permanently frozen subsoil)
Bitterly cold winters
High winds
No trees
