Principles of Ecology: Chapter 1
What is Ecology?
Ecology is the scientific study of the abundance and distribution of organisms in relation to other organisms and environmental conditions.
Ecological systems vary in size; each ecological system is a subset of the next larger one. These stacking systems form a _____________.
Hierarchy. Think Russian nesting dolls.
What is the fundamental unit of ecology? Why is it not a smaller biological unit?
An individual.
What is a population?
Individuals of the same species living in a particular area.
Give an example of a hypothetical natural natural boundary that separates populations.
ex. mountain, river, elevation difference, where a continent meets an ocean...
What is the geographic range (aka distribution) of a population?
the extent of land or water within which a population lives
What does the composition of a population refer to?
It describes the makeup of a population in terms of gender, age, or genetics
What is an ecological community?
All populations of all species living together in a particular area.
Why must scientists decide on boundaries for communities they want to study?
Because community boundaries are not always rigid. (This can manifest as communities tapering into each other between elevations for example, as opposed to a forest stopping abruptly for a beach.)
What is an ecosystem?
One or more communities of living organisms interacting with their nonliving physical and chemical environments, which include water, air, temperature, sunlight, and nutrients.
Where does most of the energy in an ecosystem come from? Where does it go?
The energy originates as sunlight and escapes earth as radiated heat.
What is the textbook's example of energy flowing into an ecosystem that DOES NOT originate as sunlight?
Energy from hydrothermal vents.
In contrast to the movement of energy, the movement of matter largely _________ within an ecosystem.
cycles
How do scientists generally distinguish ecosystems?
By their flows of energy and materials
What is the biosphere?
All the ecosystems on earth
What are the 5 levels of hierarchy of ecological systems in order of smallest to largest?
The individual, the population, the community, the ecosystem, and the environment
What are adaptations?
the characteristics of an organism that make it well-suited to its environment.
What is a phenotype?
An attribute of an organism, such as its behaviour, morphology, or physiology
What is a genotype?
The set of genes an organism carries
How are phenotypes determined?
A phenotype is determined by the interaction of the organism’s genotype with the environment it lives in.
What is evolution?
Change in the genetic composition of a population over time.
What is natural selection?
a change in the frequency of genes in a population as consequence of certain individuals reproducing with greater success than others due to their phenotypes
What are the 3 conditions natural selection depends on?
1. Individual organisms vary in their traits.
2. Parental traits are inherited by their offspring.
3. The variation in traits causes some individuals to experience higher fitness, which we define as the survival and reproduction of an individual.
What is fitness?
The survival and reproduction of an individual
What are parasites?
Organisms that live in or on another organism, called the host.
What are herbivores?
Organisms that consume producers, such as plants and algae
What is competition?
An interaction with negative effects between two species that depend on the same limiting resource to survive, grow, and reproduce
What is mutualism?
When two species interact in a way that each species receives benefits from the other (lichens)
What is a symbiotic relationship? What kind of organisms do these include?
When two different types of organisms live in a close physical relationship. Includes parasites, parasitoids, mutualists, and commensal organisms.
Are symbiotic relationships positive, negative or neutral to all parties within?
A mix of all three.
What is a habitat?
The place or physical setting in which an organism lives
What is a niche?
The range of abiotic and biotic conditions an organism can tolerate
What is the difference between a habitat and a niche? Give an example.
Habitats cover a broad area and within them are found several niches. A boreal forest is a habitat for example, but the conditions in the trees, soil and water would all make different potential niches. A species (like an earthworm) that can tolerate the conditions of its niche (soil) may not be able to tolerate the conditions of other niches (the canopy, the air) in its habitat.
No two species have exactly the same niche, true or false? Why?
True, each has distinctive attributes of form and function that determine the conditions it can tolerate, how it feeds, and how it escapes enemies.
What are the three steps we can break the scientific method into?
How does a manipulative experiment test a hypothesis?
By altering a factor that is hypothesized to be an underlying cause of a phenomenon.
The _________________, also known as the ______________, is the factor that we want to vary in an experiment.
manipulation, treatment
A ____________ is a manipulation that includes all aspects of an experiment except the factor of interest.
control
Being able to produce a similar outcome multiple times is known as...?
replication
What is Randomization?
An aspect of experiment design in which every experimental unit has an equal chance of being assigned to a particular manipulation. That particular manipulation could mean a set of conditions, interference, interactions or something else.
What are microcosms?
Simplified ecological systems that attempt to replicate the essential features of an ecological system in a laboratory or field setting.
What are natural experiments?
Experiments that rely on natural variation in the environment to test a hypothesis