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byzantiummule272Lv1

28 Sep 2019

What happens if the population overshoots its carrying capacity?This might happen, for example, if resources decreased dramaticallyfrom one year to the next, causing the carrying capacity todecrease. If population were at its old car- rying capacity, itwould suddenly find itself above its new carrying capacity. Whatwould happen?

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Beverley SmithLv2

28 Sep 2019

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Related questions

You will know if the ant population has reached the carrying capacity (K) of the 2 acre plot when __________.

a) ants are no longer born

b) ants no longer die

c) the ant birth rate equals the death rate

d) there is no longer room for ants to tunnel

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As a 4-year old child, your BIOL 1114 instructor contracted mumps, a viral disease. Although he is now middle-aged, he is immune to this disease. Which one of the following is the best hypothesis to explain this observation?

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azurewolf904

Question 1

Which is a population?

		All the members of a species inhabiting a given location.
		All the interacting populations in a given area.
		The living community and the physical environment functioning together as an independant and relatively stable system.
		All of the above

5 points

Question 2

Which is not an abiotic factor?

		Intensity of light
		type of substratum
		range of temperatures
		living things

5 points

Question 3

What does the fertility rate have to be in order to keep a population stable (neither increasing or decreasing)?

		1
		2
		3
		4

5 points

Question 4

Japan's population is falling due to a low fertility rate.

True

False

5 points

Question 5

When the population remains relatively constant over a number of years this is known as

		steady state
		abiotic state
		biotic state
		Both abiotic and biotic states

5 points

Question 6

Which are the living components of the environment?

		biotic factors
		abiotic factors
		neutrality factors
		non-organic factors

5 points

Question 7

What is carrying capacity?

		The maximum number of organisms the resources of an area can support.
		The amount of abiotic factors in an area.
		The amount of energy.
		The density of a star.

5 points

Question 8

Which can synthesize their own food?

		heterotroph
		herbivore
		autotroph
		carnivore

5 points

Question 9

Which is an example of a saprophyte?

		vulture
		bacteria
		mouse
		frog

5 points

Question 10

This consumes both plants and animals.

		Carnivore
		Herbivore
		Omnivore
		Tachivore

5 points

Question 11

Global warming might actually cause global freezing.

True

False

5 points

Question 12

There are good odds that a future virus can cause the extinction of the human race.

True

False

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Question 13

A heterotroph can make its own food.

True

False

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Question 14

According to the 1st Law of Thermodynamics, disorder always increases.

True

False

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Question 15

In 5 billion years the Sun will expand and burn up the Earth.

True

False

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Question 16

Einstein stated that World War 4 will be fought with sticks and stones.

True

False

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Question 17

Which is not true of the First Law of Thermodynamics?

		Energy cannot be created
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Question 18

According to the Second Law of Thermodynamics, the heat death of the universe is its ultimate fate.

True

False

5 points

Question 19

Which is organic?

		CH₄
		CO₂
		H₂O
		N₂

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Question 20

The Sun and the core are the primary energy sources for the Earth.

True

False

limejackal967

yeast population dynamics

Procedure

1. Work in pairs on this lab, so 12 tubes per pair of students. And share a tube rack with one other pair of students

2. Turn on your spectrophotometer. It needs at least 15 minutes to warm up to give you good readings.

3. Add 5 mL of yeast extract solution (YECM) to each of 12 tubes. (The yeast extract provides vitamins and amino acids for yeast growth and will be the same for all cultures). The tubes should be labeled with your initials, treatment, and tube number. Tape or Parafilm down the lids of 3 tubes, and label them âCONTROLâ.

Do not touch the insides of the tubes or lids! Try to keep these as sterile as possible!!

4. Add 50 mL live yeast culture to each of the remaining 9 tubes.

5. Add the varying volumes of sugar and/or ethanol using Table 1 below.

6. Use Parafilm to close the tops of each tube, making sure the Parafilm is tight and no air can get in, and label each tube with the following:

Amount of sugar added (mL) Amount of ethanol added (mL)

Name of your group Tube number

Table 1: setup yeast tubes (remember, 1 mL = 1000 mL)
Tube number	Yeast culture medium? (5 mL)	Live yeast culture? (50 mL)	Sugar added (mL)	Ethanol added (mL)
1 â control	YES	NO	0	0
2 â control	YES	NO	0	0
3 - control	YES	NO	0	0
4	YES	YES	0	0
5	YES	YES	0.25	0
6	YES	YES	0.5	0
7	YES	YES	0	0.25
8	YES	YES	0.25	0.25
9	YES	YES	0.5	0.25
10	YES	YES	0	0.5
11	YES	YES	0.25	0.5
12	YES	YES	0.5	0.5

Procedure for measuring absorbance (in absorbance units, or AU)

7. Calibrate the spectrophotometer:

Turn on the spectrophotometer and let it warm up for 15 minutes. You will get erroneous results if you donât let it warm up first.

Be sure the spectrophotometer is set to read at the wavelength of 550 nm

With no tube in the spectrophotometer and the lid closed, use the left-hand knob to adjust the reading to 0% Transmittance/push zero button to calibrate

Insert a CONTROL tube (making sure it is clear, without bacterial contamination which would make it cloudy), and use the right-hand knob to readjust the spectrophotometer to 100% Transmittance.

When reading the absorbance, be sure to line up the needle on the spec with its reflection.

8. Immediately before reading any tube, vortex the tube so that the spinning column reaches the bottom of the tube for several seconds. This is critical! The yeast cells are heavy and will tend to sink to the bottom of the tube, so you must vortex the tubes to resuspend them: otherwise, your spectrophotometer readings will be erroneously low. If the vortex is not enough to suspend the pellet of yeast cells at the base of the tube, take a piece of Parafilm and cover the top of the tube, then cover this with your thumb and shake the tube vigorously. The pellet should dislodge and the yeast cells should be easily resuspended after doing this. Use a Kimwipe to wipe down the outside of each tube, to remove fingerprints and other smudges that could affect the absorbance reading. (COULD BE A POTENTIAL ERROR)

9. Record the absorbance (in absorbance units, AU) for the tube on your data sheet.

10. Repeat steps 5 and 6 for every tube.

11. Leave the spectrophotometer turned on for the next user.

Figures you should include are:

Average absorbance vs. time for the no ethanol (0 mL) treatment

Average absorbance vs. time for the 0.25 mL ethanol treatment

Average absorbance vs. time for the 0.50 mL ethanol treatment

Sugar added vs. average carrying capacity (K). Use different symbols to denote each of the three alcohol concentrations

A. After a limit, the increasing concentration of sugar decreases the carrying capacity and growth rate. This is because at higher sugar concentrations, the medium becomes hypertonic and the yeast cells loss water towards the medium.With increasing concentration of the ethanol, the carrying capacity and the growth rate decreases. Why does this happen?

B. Is there any interaction between the effects of adding sugar and alcohol on yeast?

C. why do some cultures not reach K?

D. What are the potential sources of error and assumptions made in this experiment?

E. What do these results mean in a more general (non-yeast) context?