Disss1

Pre-Lab Questions

Terrestrial biomes are characterized by the ___ and the annual precipitation of a region.

a. Average elevation

b. Average annual temperature

c. Salinity

d. Geographic Location

What are the two primary components of an ecosystem?

2. A ___ is a location where an organism physically resides or is adapted to live.

a. Niche

b. Biome

c. Habitat

d. Trophic Level

3. What is the name for organisms that get their energy from the Sun and do not need to eat other organisms?

a. Producers

b. Primary consumers

c. Secondary consumers

d. Tertiary consumers

Ecosystems

4. What is the term for the increased concentration of a substance as it works its way up the food chain?

©eScience Labs, 2018

©eScience Labs, 2018

Exercise 1: Biomagnification

Data Sheet

Table 2. Components of the Biomagnification of DDT

Element of the Exercise	Answer
The original concentration of DDT in the water
Concentration of DDT in the plankton
How many times higher is the concentration of DDT in the plankton than in the water?
Concentration of DDT in the shrimp
Concentration of DDT in the seatrout
Concentration of DDT in the osprey
How many times higher is the concentration of DDT in the osprey than in the water?

Exercise 1 Post-Lab Questions

1. DDT is also toxic to fish and aquatic invertebrates. Based on what you know about ecosystems and food chain dynamics, what are some potential impacts to an aquatic ecosystem that receives a particularly high dose of DDT (i.e., a much higher original concentration of DDT in the water)?

2. Half-life is the time required for half of an amount of a particular compound to degrade (see table below). The half-life of DDT in the soil is from 2 to 15 years, and the half-life of DDT in an aquatic environment is 150 years.

1 half-life	50% degraded
2 half-lives	75% degraded
3 half-lives	88% degraded
4 half-lives	94% degraded
5 half-lives	97% degraded

a. How many years have passed after five DDT half-lives in an aquatic environment?

b. If the original concentration of DDT in the water is 2 ppm, how much DDT would be remaining in the water after 1 half-life?

c. How much DDT would be remaining in the water after 5 half-lives?

3. Do you think DDT has the potential to cause more long-term harm to an estuary ecosystem or a terrestrial (on land) ecosystem? Why?

Exercise 2: Studying a Miniature Ecosystem

Data Sheet

Table 3. Ecosystem Observations

Time	Observations
Day 1
Week 1
Week 2
Week 3
Other (note time)
Other (note time)

Table 4. Elements of the Terrarium Ecosystem

Abiotic Elements	Biotic Elements

Exercise 2 Post-Lab Questions

1. What are the organisms in your terrarium ecosystem?

2. What trophic levels are present in your terrarium ecosystem?

3. Give an example of an organism that is higher on the trophic pyramid than a producer that would thrive in your ecosystem.

4. What niche would the organism in Question 3 be filling in your terrarium ecosystem?

5. What adjustments to the abiotic and biotic components of your terrarium ecosystem would make it healthier?

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