Ecology Quiz 1 Flashcards
Define Ecology
Ecology is the study of the interactions of living organisms with their environment
Ecology refers to a scientific endeavor, not environmental activism.
A core goal of ecology is to understand distribution and abundance of living things in the physical environment.
Levels and Branches of Ecology In Order
Organismal Ecology
Population Ecology
Communities Ecology
Ecosystems Ecology
Biosphere/Biome Ecology
Organismal Ecology:
study adaptations that enable individuals to live in specific habitats. These adaptations can be morphological, physiologic, and behavioral. Examples like drought tolerance in desert plants to conditions where water is liming and polar bears living in the arctic.
Population Ecology:
A group of individuals of a single species that live in a particular area and interact with one another.
together all the pine trees make up a population. focus on the number of individuals in an area and how and why population size changes. Examples like deer population growth in a given area over time.
Communities Ecology:
An association of populations of different species living in the same area at the same time.
represent all the plant and animal species that comprise a community. study the processes driving interactions between species, as well as their consequences. Example plant pollinator interactions and their influence on plant species abundance.
Ecosystems Ecology:
A community of organisms plus their physical environment.
study the storage and movement of nutrients and energy among organisms and the surrounding atmosphere, soil, and water. Example carbon cycling in a boreal forest.
Biosphere/Biome Ecology:
(highest level of organization and encompasses all) earth image so everything
Landscapes:
Areas with substantial differences, typically including multiple ecosystems
Direct vs. Indirect Interactions
Even species that do not interact directly can be connected by shared environmental features.
Relationships between members of an ecological community can be classified within two broad categories, direct effects and indirect effects. The first of these, direct effects, as the name implies, deals with the direct impact of one individual on another when not mediated or transmitted through a third individual. If you have ever watched a cheetah capture a gazelle or a bee pollinate a flower, then you have observed a direct effect in action. There are eight main types of direct effects which are classified by the net effect of the relationship on each individual; positive, negative, or neutral.
The second major class of interactions, indirect effects, can be defined as the impact of one organism or species on another that is mediated or transmitted by a third. In other words, A (donor) has an effect on B (transmitter), which then affects C (recipient). There are two main ways by which an indirect effect can occur. The first is known as an interaction chain, in which a donor species affect the abundance of a transmitter and has an effect on a recipient. When a bird species (donor) begins to aggressively prey upon a specific caterpillar (transmitter), the reduction in herbivory by the caterpillars can lead to increased growth or numbers of the plants the caterpillar was consuming (recipient).
Explain why ecology is important to understanding of the natural world and human endeavors
Ecologists ask questions about the natural world in order to understand these connections.
Humans have an enormous impact on the planet - emission of greenhouse gasses, extract resources which leads to destroying habitats, invasive species
Important how natural systems work to meditate the consequences of human impact
Early views of ecological systems
There is a “balance of nature” in which natural systems are stable and ten to return to an original state after disturbance - this is not how we view ecosystems today
Each species plays a distinct role in that balance
Superorganism: Frederick Clements states that ecological communities are superorganisms that each species in a community has a particular role in the function of the ecosystem. Each community has different species that are contained in each community. Each community is its own unit and when disturbed you have predictable and repeatable succession of plants reaching the climax community.
Individualistic Hypothesis: Henry Gleason said each species has a different set of preferences and can tolerate different variables and has their own environmental requirements. Associations are complete coincidences. Associations are “not an organism, scarcely even a vegetation unit, but merely a coincidence”
Mutualism like fungi dependent on tree hosts aligns with the superorganism but in general the individualistic hypothesis holds true.
Contemporary views of ecological systems
- Communities resemble a loose collection of organisms with their own set of preferences
- Random processes and perturbations can play an important role and can structure communities.
- Different communities can form in the same area under similar environmental conditions.
Example: two lakes meters apart carry different stuff like one more dirty - Natural systems do not necessarily return to their original state after disturbance.
- Ecological interactions are more complex than previously thought.
Example: mutualism meaning there are a lot of interactions - One view has not changed: Events in nature are interconnected. A change in one part of an ecological system can alter other parts of that system.
Superorganism VS Individualistic Hypothesis
Superorganism: Frederick Clements states that ecological communities are superorganisms that each species in a community has a particular role in the function of the ecosystem. Each community has different species that are contained in each community. Each community is its own unit and when disturbed you have predictable and repeatable succession of plants reaching the climax community.
Individualistic Hypothesis: Henry Gleason said each species has a different set of preferences and can tolerate different variables and has their own environmental requirements. Associations are complete coincidences. Associations are “not an organism, scarcely even a vegetation unit, but merely a coincidence”
Spatial scales:
Small—e.g., soil microorganisms
Large—e.g., atmospheric pollutants
Temporal scales:
Short—e.g., leaf response to sunlight
Long—e.g., species change over geologic time
Evolution:
- Change in genetic characteristics of a population over time.
- Descent with modification— organisms gradually accumulate differences from their ancestors.
Adaptation:
A characteristic that improves survival or reproduction.
Natural selection:
Individuals with certain adaptations tend to survive and reproduce at a higher rate than other individuals.
Ecosystem processes:
Producers (autotrophs) use energy from an external source (e.g., the sun) to produce their own food. Also called primary producers.
Net primary production (NPP): Energy captured by producers minus amount lost as heat in cellular respiration.
Consumers (heterotrophs) get energy by eating other organisms or their remains.
Energy captured by producers is eventually lost from the ecosystem as metabolic heat.
Energy moves through ecosystems in one direction only—it can’t be recycled.
But nutrients are continuously recycled from the physical environment to organisms and back again—this is the nutrient cycle.
How do ecologists answer ecological questions?
No single approach works in all situations, so ecologists use a variety of methods
The scientific method: observation, critical question, develop hypothesis, make prediction that can be tested, perform experiment to test prediction, results, interpret and conclude
Control: Stays the same acts as a reference
Principles are rare in ecology bc its contextual
Observational studies: Advantages - does not need a lot of manipulations, cost effective, can be very narrow, hard to mimic real conditions, large scale questions can see all the interactions. Disadvantages - slow process, can’t identify all influencing variables rely on correlations. Observational studies draw inferences from samples to a population
The independent variable is not under the control of the ecologist
Lab experiments: Advantages - reducing variation to very controlled, isolate and manipulate, see cause and effect, different instruments that can apply in field Disadvantages - not in natural environment so less variation so reduction
Field experiments: less control but causational relationships
Modeling: large scale time scale questions and limitations if data is bad then bad
Experimental design:
Replication—performing each treatment more than once; reduces possibility that results are due to a variable that was not measured or controlled in the study.
Assign treatments at random— also limits the effects of unmeasured variables.
Analyze results using statistical methods: standardized ways to determine whether observed differences are significant (great enough to be of biological importance).
Trophic Level Orders
Producers: Plant
Primary Consumers
Secondary Consumers
Tertiary Consumers
Decomposers such as bacteria and fungi
