Question

name: kayleigh h...
period: 5th
date: 9/5/25
u1l8-13 lions assess. #2 study guide
unit 1 africa - assessment #2
individual (paper)
review for midpoint assessment on tues 09.09.25
lesson 8: how is energy used in organisms?

(kg) | organism a | organism b
amount ingested | 10.7 | 24.3
amount needed to maintain biomass | 63.0 | 84.0
amount egested | 30.4 | 42.1
what’s “missing”?

1. what is “missing” from each organism? what does the “missing” energy get used for in the organism?
2. if organism b eats organism a, what energy is directly available to organism b from organism a?
3. provide evidence to back up your claim in question #2 (use what we learned in lesson 8 to help you!)

% of energy used efficiently
organism a: 24% | organism b: 57%

1. based on the table above, which organism is the least efficient with their energy? how do you know?

lesson 9: animal nutrition lab
write a cer to answer the driving question.
*** digestive tract on next page! use both images!!!
driving question: what type of eater would the organism to the right be?
claim:
** “this organism is a __________ (herb., omniv., carn.).”
image of a skull with teeth

Explanation:

Question 1:

Step1: Recall energy flow in organisms

In an organism, the energy ingested is used for maintaining biomass, egested (excreted as waste), and the remaining is used for cellular respiration (metabolic processes like growth, movement, reproduction, etc.). The formula for the "missing" energy (used for respiration) is: \( \text{Missing Energy} = \text{Amount Ingested} - \text{Amount Needed to Maintain Biomass} - \text{Amount Egested} \)

Step2: Calculate for Organism A

For Organism A: \( \text{Missing Energy}_A = 10.7 - 63.0 - 30.4 \)? Wait, no, wait, maybe I mixed up. Wait, actually, the correct approach is that the energy ingested is allocated to: energy for maintenance (to stay alive, maintain biomass), energy egested (waste), and energy used for respiration (the "missing" part, used for life processes like growth, reproduction, movement, cellular activities). So the correct formula is: \( \text{Ingested} = \text{Maintenance} + \text{Egested} + \text{Respiration (Missing)} \). So \( \text{Respiration} = \text{Ingested} - \text{Maintenance} - \text{Egested} \)

Wait, but for Organism A, Ingested is 10.7, Maintenance is 63.0? That can't be, because 10.7 is less than 63.0. Maybe there's a typo, or maybe the units are different? Wait, maybe the "Amount Needed to Maintain Biomass" is per unit time, and Ingested is also per unit time. Wait, maybe I misread the numbers. Let me check again.

Organism A:

• Amount Ingested: 10.7 kg
• Amount Needed to Maintain Biomass: 63.0 kg
• Amount Egested: 30.4 kg

Wait, that would mean \( 10.7 = 63.0 + 30.4 + \text{Respiration} \), which would give a negative respiration, which doesn't make sense. Maybe the numbers are reversed? Maybe "Amount Needed to Maintain Biomass" is the energy used for maintenance, and Ingested is the total energy taken in. Wait, maybe the table has a mistake, or maybe I misinterpret the columns. Alternatively, maybe "Amount Needed to Maintain Biomass" is the energy stored or used for growth, and the "missing" is respiration. Wait, perhaps the correct formula is \( \text{Ingested} - \text{Egested} = \text{Assimilated} \), and then \( \text{Assimilated} = \text{Maintenance} + \text{Respiration} + \text{Growth} \). But the table says "Amount Needed to Maintain Biomass", maybe that's the maintenance energy. So \( \text{Assimilated} = \text{Ingested} - \text{Egested} \), then \( \text{Respiration} = \text{Assimilated} - \text{Maintenance} \)

Let's try that. For Organism A:

• Assimilated = 10.7 - 30.4 = -19.7. Still negative. That can't be. So maybe the numbers are in grams or another unit? Or maybe the table has a typo. Alternatively, maybe "Amount Ingested" is 107 instead of 10.7? Let's assume it's a typo, maybe 107. Then:

Organism A:

• Ingested: 107
• Maintenance: 63
• Egested: 30.4
• Assimilated = 107 - 30.4 = 76.6
• Respiration = 76.6 - 63 = 13.6

Organism B:

• Ingested: 243 (maybe typo, 24.3 is too small)
• Maintenance: 84
• Egested: 42.1
• Assimilated = 243 - 42.1 = 200.9
• Respiration = 200.9 - 84 = 116.9

But since the original numbers are 10.7, 24.3, maybe the units are different, like kilojoules instead of kilograms? Because mass and energy are different. Maybe the table has a mistake in units. Assuming the units are energy (like kJ), then:

For Organism A:
Ingested: 10.7 kJ
Maintenance: 6.3 kJ (maybe a decimal mistake, 63.0 is too big)
Egested: 3.04 kJ

Then Assimilated = 10.7 - 3.04 = 7.66 kJ
Respiration = 7.66 - 6.3 = 1.36 kJ

Alternatively, maybe the "Amount Needed to Maintain Biomass" is the energy used for growth and maintenance, and the "missing" is respiration.…

Step1: Compare efficiency percentages

Organism A has 24% energy used efficiently, Organism B has 57%.

Step2: Determine least efficient

Efficiency is the percentage of energy used for useful purposes (like growth, reproduction, or maintaining biomass). A lower percentage means less energy is used efficiently. Since 24% < 57%, Organism A is the least efficient.

Answer:

1. The "missing" energy is the energy used for cellular respiration (powering life processes like growth, movement, reproduction, and cellular functions). For Organism A: \( 10.7 - 63.0 - 30.4 \) (assuming units are correct, but likely a typo; with corrected numbers, it's the energy for respiration). For Organism B: similarly, the energy for respiration.
2. The energy directly available to Organism B from Organism A is the energy in Organism A's biomass (e.g., 63.0 kg of energy, assuming corrected units).
3. Evidence: Energy flow in ecosystems shows that the energy available to a predator is the prey's assimilated energy minus its respiration energy, which equals the prey's biomass energy (from the table, "Amount Needed to Maintain Biomass").
4. Organism A is the least efficient. We know this because its % of energy used efficiently (24%) is lower than Organism B's (57%).

(Note: The table likely has a typo in the "Amount Ingested" or "Amount Needed to Maintain Biomass" values, as the given numbers for Organism A result in a negative energy balance, which is biologically impossible. Assuming corrected values, the above explanations hold.)