Lab practical 1 Study Guide

Define/describe sustainability based on the US EPA’s definition.

According to the United States Environmental Protection Agency, sustainability is everything that we need for our survival and well being depends, either directly or indirectly, on our natural environment.

Define/describe the UN definition of sustainable development.

A form of development that “meets the needs of the present without compromising the ability of future generations to meet their own needs”.

Explain the concept of the “Tragedy of the Commons”. Provide an example of a “commons” and explain how the Tragedy of the Commons could impact the resources of the commons.

Describes a situation where individuals with access to a public resource (common) take full advantage of it and act in their own selfish wants, needs, and interest. Resulting in that resource depleting, disappearing, or being eliminated. 

What is “carrying capacity”?

Refers to the maximum number of individuals of a species that an environment / ecosystem can sustainably support over time. 

What typically happens to a population of organisms when its population size exceeds the carrying capacity of the environment? List several reasons why this happens. 

The population enters a state called “overshoot”. Overshoot is defined as to shoot pass, over, or beyond. This could happen because of climate change, reproductive lag times 

Describe the concept of an “ecological footprint”. What kinds of factors go into determining an individual’s ecological footprint?

An ecological footprint is defined as the area of productive surface / land that is required to create the biomass needed to keep up with human consumptions or waste absorption like the carbon emissions from fossil fuels. 

An ecological footprint is calculated by The global footprint network. They gather / obtain information from official organizations like the United Nations and other well-known and trusted groups. They obtain this information annually from most of the countries in the world and contrast and aggregate it to get a bigger and more clear picture of how much ecological footprint we use around the world. 

Define biocapacity.

The area of biologically productive land and ocean area to provide food, fiber, and timber. As well as accommodate urban infrastructure, and absorb excess CO2. 

What factors can decrease a country’s biocapacity?

Deforestation, climate change, urbanization, etc

Define biocapacity deficit.

When a population's ecological footprint exceeds the biological capacity of its surrounding environment to regenerate resources and absorb waste. 

Define ecology.

The scientific study of how living organisms interact with one another and with their physical, non-living environment. 

Define population.

All members of one species in a given area. 

Explain how a mark-recapture study is conducted. 

capturing an initial sample of the organism, marking them, releasing them to mix back into the wild, and taking a second sample to see how many marked individuals are recaptured. 

Explain why a mark-recapture study is conducted.

To estimate the size of a population. 

What are the 4 “assumptions” of the mark-recapture technique?

1. The population is closed: No individuals are added or removed (births, deaths, immigration, or emigration) between the two captures.

2. Marks are not lost or overlooked: The marked individuals retain their marks and are correctly identified during recapture.

3. Marked and unmarked individuals have the same chance of being captured: Marking does not affect an individual's likelihood of being caught.

4. Recaptures are random: The captured sample is representative of the entire population, with no bias toward certain individuals.

Define carrying capacity.

The number of individuals an environment can support. 

Identify density-dependent factors that influence carrying capacity.

Competition for resources, predation, disease and parasites, waste accumulation, territoriality. 

Identify density-independent factors that influence carrying capacity. 

Natural disasters, climate, weather, pollution, human activities. 

What is exponential growth?

When the population growth starts off very slowly and then gets faster.

What does a graph of exponential growth look like?

A continuous, upward-curving line that starts relatively flat and gradually becomes almost perfectly vertical. Often called a “J” curve. 

What factors cause a population to experience exponential growth?

When there is enough food, space, and other resources for every single bacterium. 

What is logistic growth?

A pattern of population growth that occurs when a populations increase slows and eventually stabilizes as it approaches the carrying capacity of its environment. Take into account environmental limitations. 

What does a graph of logistic growth look like?

“S” shaped curve 

What factors cause a population to experience logistic growth?

When resources become limited, causing population growth to slow and eventually stabilize. 

Define keystone species.

An organism that plays an important role in its ecosystem, their presence is crucial in maintaining environmental balance and keeping it healthy. 

Explain what a trophic cascade is.

When you have an apex predator controlling the distribution of resources, and they lead to these cascades of indirect effects. 

What happens if a keystone species is removed from a community?

Their entire ecosystem can collapse. 

Define demography.

The scientific study of human populations. 

What three rates are considered when studying demography statistics?

Fertility rate, mortality rate, migration rate. 

Define “crude birth rate”.

A demographic metric that measures the annual number of live births per 1,000 people in a scientific population

Define “crude death rate”. 

A basic demographic metric that measures the total number of deaths in a specific population over a given period, divided by the total mid-year population, and expressed per 1,000 people. 

What are some methods biologists use to trap and study organisms?

Baiting traps for small animals 

Digging pitfall traps for lizards

Using dung to lure in beetles

Climbing into a tree canopy for rare insects and plants 

What is an indicator species?

A species that gives us clues about the health of the entire habitat

Define biome.

A large, distinct geographical region on earth defined by its climate, soil, and the specific plants and animals that have adapted to live there. 

What two factors determine which biome will exist in a particular area?

Temperature and precipitation

What is the difference between “richness” and “evenness” when referring to biodiversity?

Richness: the absolute number of unique species present in a specific habitat or community 

Evenness: How evenly the individuals in a community are distributed among those species. 

Explain why biodiversity is important and why it should be studied.

It provides ecosystem services and provides over half of all modern medicines. Studying it helps us develop conservation strategies and prevent food shortages. 

What are the differences between gray, black, and red soils?

Grey soil: indicates the highest water table depth during the wettest part of the year and overall wetness of the soil. 

Black soil: indicates a high amount of organic matter as compared to those that are lighter brown in color. 

Red soil: indicates high amounts of iron due to microbial medicated reactions. 

What is humus?

A portion of the makeup of soil that is composed of plant matter, macroscopic organisms, and microscopic organisms. This enables soil to resist changes in pH. 

What is infiltration rate?

How fast water can enter the soil. 

In addition to humus, what three components make up soil?

Sand, silt, and clay. 

What soil characteristic determines how much air and water can enter soil?

Particle size.