Chapter 1 Flashcards
What is ecology?
the scientific study of the abundance and distribution of organisms in relation to other organisms and environmental conditions.
Ecological systems
Biological entities that have their own internal processes and interact with their external surroundings
Individuals
the most fundamental unit of ecology.
Individuals acquire nutrients and energy,
and produce waste.
Individuals have a membrane boundary that separates internal processes from the external environment.
Populations
individuals of the same species living in a particular area.
Geographic range (distribution) is the extent of land or water within which a population lives.
Abundance is the total number of individuals.
Density is the number of individuals per unit area.
Composition is the makeup in terms of age, gender, or genetics.
Communities
Populations of species living together in a particular area.
Includes many types of interactions, such as predation and competition.
Ecosystems
one or more communities of living organisms interacting with their nonliving physical and chemical environments.
Research is focused on movement of energy and matter between physical and biological components.
This includes the “flow” of material from “pools” of elements, such as carbon, oxygen, hydrogen, nitrogen, and phosphorus.
The biosphere
all ecosystems on Earth.
Distant ecosystems are linked together by exchanges of wind and water and by the movement of organisms.
Individual approach
Understands how adaptations, or characteristics of an individual’s morphology, physiology, and behavior enable it to survive in an environment.
Population approach
Examines variation in the number, density, and composition of individuals over time and space.
Community approach
Understands the diversity and interactions of organisms living together in the same place.
Ecosystem approach
Describes the storage and transfer of energy and matter.
Biosphere approach
Examines movements of energy and chemicals over the Earth’s surface.
Evolution
a change in the genetic composition of a population over time.
Natural selection
A change in the frequency of genes in a population through differential survival and reproduction of individuals that possess certain phenotypes.
Three requirements
- Individuals vary in their traits.
- Traits are heritable.
- Variation in traits causes some individuals to experience higher fitness (survival and reproduction).
prokaryotes
First organisms without distinct organelles.
Can utilize sources of energy that most other organisms cannot, such as N2 and H2S gas.
Protists
Eukaryotes that include protozoa, some algae, and slime molds.
Some protists can grow very large and look like large plants (e.g., kelp).
fungi
have hyphae that extract nutrients from dead or living tissues.
They secrete acids, and enzymes digest food externally.
Many are decomposers and many are plant mutualists.
Producers
or autotrophs—convert chemical energy into resources.
Consumers
or heterotrophs—obtain their energy from other organisms.
Mixotrophs
can switch between being producers and consumers.
Detritivores
break down dead organic matter (i.e., detritus) into smaller particles.
Decomposers
break down detritus into simpler elements that can be recycled.
Predation
when an organism kills and consumes an individual.
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Parasitism
when one organisms lives in or on another organism.
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Herbivory
when one organism consumes producers.
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Competition
when two organisms that depend on the same resource have a negative effect on each other.
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Mutualism
when two species benefit from each other.
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Commensalism
when two species live in close association and one receives a benefit, whereas the other is unaffected.
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Habitat
The place, or physical setting, where an organism lives. Distinguished by physical features, such as dominant plant type.
Niche
the range of abiotic and biotic conditions an organism can tolerate.
Example: Different insects prefer to feed on different crop species that may be growing in the same field.
Hypotheses
ideas that potentially explain a repeated observation.
Proximate hypotheses
address the cause of immediate changes in individual phenotypes or interactions.
Ultimate hypotheses
address the fitness costs and benefits of a response.
Randomization
a requirement for manipulation experiments; every experimental unit must have an equal chance of being assigned to a particular treatment.
Mathematical models
representations of a system with a set of equations that correspond to hypothesized relationships among the system’s components.
Ecologists often test mathematic models using natural or manipulative experiments.
Greenhouse gases
compounds in the atmosphere that absorb infrared heat energy emitted by Earth and then emit some of the energy back toward Earth. High amounts of these gases can increase average Earth temperatures.
