Bio 103, Lab 10: Genes, Environment, Selection

Paul Grobstein's picture
Last lab, we studied inheritance and recognized that there is an important distinction between genotype and phenotype. This week we want to look at the role that genes, environmental factors, and selection play in an organism's phenotype. To do so we will look at the phenotypes of populations of the plant Brassica rapa ("fast plants").

The plants you'll be looking at were all seeded at the same time several weeks ago. There are two genetically different populations (A and B) and each was grown under four different conditions (high light and fertilizer, low light and high fertilizer, high light and low fertilizer, low light and low fertilizer). To get started, examine specimens of each with the following questions in mind. Neither population is genetically homogenous, so keep in mind that there may be some variation due to unknown genetic factors.

  • Do genes affect plants?
  • Do environmental variables affect plants?
  • Are there characteristics that are affected only by genes, only by the environment, by both?

The answers to these questions are likely to be different for different plant characteristics. After looking generally at the plants, pick several different qualitative and/or quantitative characteristics to study in more detail. Among the latter, include a particular quantitative characteristic of these plants: the number of petiolar trichomes on the first true leaf. Describe relevant observations and interpretations in the lab forum area.

We will compare data on the number of petiolar trichromes in our plants with data from other laboratories in populations derived from ours by using as parents only those individuals having a number of trichomes greater than 90% of the population to determine if this characteristic is subject to evolutionary change.

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multiyearheritability.xls29.5 KB
Anonymous's picture

dwarf plants

do you guys have your controlled height ? THanks

ekoike's picture

Environmental and Genetic Variables as a factor in Phenotype

Crystal Reed and Eri Koike

In this lab, we selected four characteristics of the plants (height until the first leaf, height of tallest part of plant, amount of buds on the plant and the stem color and thickness of the stem) in order to determine what factors were influenced by genes, environmental conditions and random genetic variations.

In our first of a series of observations, we counted the amount of buds on the tallest part of the plant. We initially predicted that the environmental conditions (in our case fertilizier) would affect the number of buds.

Wild Type LL HF: 21 buds

Wild Type LL LF: 10 buds

Petite LL HF: 15 buds

Petite LL LF: 10 buds

Through these two observations, we can find that the environmental conditions, which was in our case high vs. low fertilizer, drastically influences the amount of buds on the tallest part of a plant.

Wild Type HL HF: 27 buds

Wild Type HL LF: 9 buds

Petite HL HF: 22 buds

Petite HL LF: 8 buds

Through our additional observations, we found that fertilizer has more of an impact than light and the type of seed. We found that although the standard did tend to have a slightly larger number of buds, there were other instances where the standard had less or the same as the petite. Therefore, we found that the environmental factors (specifically the fertilizer) had more of an impact on the bud phenotype than the genetic factors.

 

In our next set of observations, we decided to look at the height until the first leaf and the height of the tallest plant. We initially predicted that the type of seed (wild vs. petite) and the environment (High/low fertilizer) would influence the height of the plants.

Changes in High/Low Fertilizer in Low Light:

Wild Type LL HF: (Height until first leaf) 2 in.; (Height of tallest plant) 6.75 in.

Wild Type LL LF: 3.125 in.; 6 in.

Petite Type LL HF: 1.75 in.; 5 in.

Petite Type LL LF: .9375 (15/16) in.; 3 in.

Changes in High/Low Fertilizer in High Light:

Wild Type HL HF: .75 in.; 9.5 in.

Wild Type HL LF: .125 in.; 1.75 in.

Petite Type HL HF: .0625 in.; .1825 in.

Petite Type HL LF: .125 in.; 1.75 in.

In this observation, we found that different environmental conditions work well for the growth of different types of plants. In the wild type plants, the best condition for growth was in high light and high fertilizer. Although we predicted that would be the result for both types of seeds, we found in the petite type that in fact low light and high fertilizer helps it to grow the tallest. For the height to first leaf, we found that it is greatly affected by light but also to a lesser degree by genes.

Therefore, we can state that each plant has its own optimal conditions that it can thrive in.

 

Our next set of observations has to do with the stem color and thickness of the stems. We initially predicted that the seed type would influence the color and thickness as well as the environmental factors.

Wild Type LL HF: Light green; 3/32 in. thick

Wild Type LL LF: Light purple; 1/32 in. thick

Petite Type LL HF: Dark purple; 2/32 in. thick

Petite Type LL LF: Medium Purple; 1/32 in. thick

Wild Type HL HF: Medium Green; 3/32 in. thick

Wild Type HL LF: Dark Purple; 2/32 in.

Petite Type HL HF: Dark Green; 4/32 in.

Petite Type HL LF: Dark Purple; 1/32 in.

Through this set of observations, we found that the petite type plants tended to be darker in stem shade except when high light was applied to the wild type. So therefore, we can state that the genetics had to do more with stem color than the environmental conditions and the stem thickness was heavily influenced by the environmental factors (since the stem was thickest in the high fertilizer)

And finally, our last set of observations has to do with the number of trichomes on the petiola of the first leaf.

Wild Type LL HF: 3 petiolar trichomes

Wild Type LL LF: 6 petiolar trichomes

Petite Type LL HF: 0 petiolar trichomes

Petite Type LL LF: 0 petiolar trichomes

Wild Type HL HF: 4-6 petiolar trichomes

Wild Type HL LF: 1 petiolar trichomes

Petite Type HL HF: 0 petiolar trichomes

Petite Type HL LF: 17 petiolar trichomes

Through these set of observations, we can conclude that generally, the number of petiolar trichomes has to do with seed type (*There is one outlier to this case in the Petite Type HL LF where there were 17 trichomes.*) and that environmental factors don't have any influence on the number of trichomes.

Shanika's picture

Shanika, Lakesha, Sharhea

Today, we did an investigation on plants. Below you will find our analysis:

Height (inches) Petiole Trichomes
Low Light, Standard, High Fertilizer 4 1
Low Light, Standard, Low Light 3.25 11
Low Light, Petite, High Fertilizer 3.87 n/a
Low Light, Petite, Low Fertilizer 2.5 n/a
High Light, Standard, High Fertilizer 4.125 26
High Light, Standard, Low Fertilizer 2.125 4
High Light, Petite, High Fertilizer 4.375 n/a
High Light, Petite, Low Fertilizer 1.625 n/a

 

From our observations, we could see that the environment does affect the plant. The plants placed in the High Light, High Fertilizer, whether standard or petite, grew a lot taller than the other plants. The high fertilizer also made a difference in height for the plants in the low light. The difference in genes was apparent in the petiolar trichomes because the petites did not have any hairs and the standards had a range of amount of hair growth. We think that plants are affected by both the environment and genes, not just one factor affects how the plant grows and how fast. 

kgould's picture

Luisana, Andy, Kate

In this lab we chose three characteristics to compare between the different plants. The data we gathered was of the following eight specimens:

1) LL, S, HF (low light, standard, high fertilizer)

2) LL, S, LF (low light, standard, low fertilizer)

3) LL, P, HF (low light, petite, high fertilizer)

4) LL, P, LF (low light, petite, low fertilizer)

5) HL, S, HF (high light, standard, high fertilizer)

6) HL, S, LF (high light, standard, low fertilizer)

7) HL, P, HF (high light, petite, high fertilizer)

8) HL, P, LF (high light, petite, low fertilizer)

The characteristics we looked at were: the number of petriolar trichomes on the first true leaves, height, and foliage (number of leaves).

Petriolar trichomes on the first true leaves (an average):

1) LL, S, HF: 5

2) LL, S, LF: 1

3) LL, P, HF: 2

4) LL, P, LF: 5

5) HL, S, HF: 4

6) HL, S, LF: 8

7) HL, P, HF: none

8) HL, P, LF: 10

--No correlation that we could find. 

Height (on average):

1) LL, S, HF: 14

2) LL, S, LF: 9

3) LL, P, HF: 11

4) LL, P, LF: 4

5) HL, S, HF: 18

6) HL, S, LF: 3

7) HL, P, HF: 11

8) HL, P, LF: 3

--There is a definate correlation between height and fertilizer: the high fertilizer plants are taller. 

Foliage (number of leaves) (on average):

1) LL, S, HF: 7

2) LL, S, LF: 2

3) LL, P, HF: 4

4) LL, P, LF: 3

5) HL, S, HF: 6

6) HL, S, LF: 1

7) HL, P, HF: 5

8) HL, P, LF: 2

--There is also a correlation between foliage and fertilizer: the plants with more leaves were those with high fertilizer. 

Observations:

LL, S, HF and HL, S, HF are both "droopy;" that is, instead of growing vertically they chose to grow outward, or horizontally, in a curve.

Forty-five minutes into the experiment and all of the high-fertilizer plants are drooping.

HL, P, HF had no trichomes on the petrioles because the leaf directly grew from the main stem of the plant.

Low light yielded taller plants in both varieties, but the stems were slimmer than those of high light plants.  

According to our data, the environmental factors, (namely that of fertilizer), made the most difference on the varying characteristics of the plants. The high fertilizer plants grew the tallest and produced the most foliage, where as the low fertilizer plants were smaller and produced only a sparse amount of foliage.

It is obvious that there is a general difference between the standard and petite plants in terms of height, but it seems that genes only play a basic role in height; fertilizer affected the height of the plants more than the genes. 

kcough's picture

*Flower Power*

Elizabeth Harnett, Rachel Tashjian, Kaitlin Cough

 

Environmental Variable (Fertilizer Variance) Looking at number of blooming flowers (BF), height (H), and petiolar trichomes (PT):

Observations:

PT: High fertilizer=more PT (generally)

BF: High/Low fertilizer alone doesn’t seem to have any bearing on the number of blooming flowers

H: High fertilizer=taller plants

Conclusions:

The higher fertilizer increases the height of all seed genotypes (both petite and standard). It does not, however, have any affect on the number of blooming flowers, though it does seem to increase the number of Petiolar Trichomes in both genotypes. Petite seeds in general have fewer or no Petiolar Trichomes, except in Oswald’s case. (As a side note, high lights, except for Bruce, seem to have more blooming flowers than low lights)


Low light, standard seed, high fertilizer=Jorge:

BF: 2

H: 17 cm

PT: 9

Low light, standard seed, low fertilizer=Jane:

BF: 3

H: 11.5 cm

PT: 1

Low light, petite seed, high fertilizer=Oswald:

BF: 8

H: 12.5

PT: 9

Low light, petite seed, low fertilizer=Bitsy Von MuffinTramp III:

BF: 2

H: 5.5 cm

PT: 4

High light, standard seed, high fertilizer=Bruce:

BF: 4

H: 23 cm

PT: 3

High light, standard seed, low fertilizer=Miller:

BF: 23

H: 10.6

PT: 4

High light, petite seed, high fertilizer=Joseph Stalin:

BF: 34

H: 18.5

PT: 0

High light, petite seed, low fertilizer=Annabelle VIII:

BF: 16

H: 4.3

PT: 0


With Genetic Variable (standard seed vs. petite seed), Looking for height, petiolar trichomes, and number of blooming flowers:

Observations:

Seed: no bearing on flowers (50/50)

Height: Standard seeds are taller

Petiolar Trichomes: while petite seeds with low light have an equal or greater number of petite seeds than standard seeds with low light, petite seeds with high light seem to have fewer PT than standard seeds with high light.

Conclusions:

The variation of genotypes has no bearing on the number of blooming flowers, though high lights in the case also seem to have more blooming flowers. The height was affected by the genotype—standard seeds are considerably taller than petite seeds. While petite seeds with low light have an equal or greater number of Petiolar Trichomes than standard seeds with low light, petite seeds with high light seem to have fewer PT than standard seeds with high light.


Low light, standard seed, high fertilizer=Jorge:

BF: 2

H: 17 cm

PT: 9

Low light, petite seed, high fertilizer=Oswald:

BF: 8

H: 12.5

PT: 9

Low light, standard seed, low fertilizer=Jane:

BF: 3

H: 11.5 cm

PT: 3

Low light, petite seed, low fertilizer=Bitsy Von MuffinTramp III:

BF: 2

H: 5.5 cm

PT: 5 (one leaf only with hair on it, rest of leaves are naked)

High light, standard seed, high fertilizer=Bruce:

BF: 4

H: 23 cm

PT: 3

High light, petite seed, high fertilizer=Joseph Stalin:

BF: 34

H: 18.5

PT: 0

High light, standard seed, low fertilizer=Miller:

BF: 23

H: 10.6

PT: 4

High light, petite seed, low fertilizer=Annabelle VIII:

BF: 16

H: 4.3

PT: 0


What characteristics do genetics affect? Height, possibly Petiolar Trichomes

What characteristics do environment affect? Height, number of blooming flowers

Based on our data, our story is that genetics and environment affect all aspects of growth.

ekim's picture

on genetic and environmental effects.

Vivian Cruz, Eurie Kim

In this experiment, we tested the traits of height, color, number of flowers (per stem), and petiolar trichromes.

Height
STANDARD
LLSLF 14.9 cm
HLSHF 22.8 cm
HLSLF 8.1 cm
LLSHF 16.2 cm

avg. 15.5 cm

PETITE
LLPLF 4.6 cm
HLPHF 9.2 cm
HLPLF 3.4 cm
LLPHF 13.0 cm

avg. 7.55 cm

*From these observations, we can tell that the plants with STANDARD genes were taller than the plants with PETITE genes (on average). However, there was also variation in height within each gene group. For instance, the plants with HIGH FERTILIZER within each genetic group were taller than those with LOW FERTILIZER.
*This shows that both genetics and the environment play a role in determining height, but genetics lays a foundation for the trait (and from that foundation, depending on the environment the plant would grow taller than others, or not).

Color
STANDARD
lighter-colored leaves
HLSLF - lower-level leaves had reddish tint

PETITE
darker-colored leaves
HLPLF - lower-level leaves also had reddish tint

*Seeing that there is a general color difference between the two gene groups, genetics affect color, however, in both gene groups, the HIGH LIGHT, LOW FERTILIZER plants both had reddish-tinted leaves, showing that the environment could also affects the leaves' color.

Petiolar Trichromes
STANDARD
HLSLF 11 hairs
HLSHF 14
LLSLF 5
LLSHF 5

PETITE
HLPLF 0
HLPHF 0
LLPLF 4
LLPHF 0

*The PETITE plants generally don't have hair with the except of LLPLF, which did have 4 hairs. This shows that there is still variation within a gene group. Furthermore, within the STANDARD group of plants, the HIGH LIGHTS generally had more hair than the LOW LIGHTS, which also shows that the environment could affect this trait.

Our Story
Both genetics and environment affect traits.

Kendra's picture

Discovering Differences: Environmental and Genetic Influences

Kendra Sykes, Ashley Savannah, and Kerlyne Jean

We tested four different characteristics of the plants. These were: petioral trichomes, height, number of flowers, and number of leaves.

Our first experiment for the petioral trichomes our results were as follows:

wild type HL HF: avg. 15.5

wild type HL LF: avg. 10.25

This shows that the environment has an influence on the number of petioral trichomes.

wild type LL LF: avg. 2.7

petite LL LF: avg. 5.5

This shows that genome does not have an influence on the number of petioral trichomes because it showed up on both though the numbers were different.

The next experiment was height and we hypothesized that bothe environment and genome would influence height our results were the following:

wild type HL HF: avg. 16.25 cm

wild type HL LF: avg. 6.5 cm

This shows that environment does have an influence on the height of the plant because the heights were significantly different.

wild type LL LF: avg. 9.8 cm

petite LL LF: avg. 3.18 cm

This also shows that genome has an influence on the plant because almost all the plants of the wild type were taller than the petite genome. We now see that both environment and genome has an in fluence on height.

The next experiment was the number of flowers on the plants and we hypothesized that environment would have an affect and that genome would not. These are our results:

wild type HL HF: avg. 2.2 flowers

wild type HL LF: avg. 3.7 flowers

Since the difference in number of flowers is so small a clear conclusion cannot be made on whether environment affects the number of flowers.

wild type LL LF: avg. 1 flower

petite LL LF: avg. 0 flowers

The genome may or may not affect the number of flowers in each group of four plants but maybe if buds were counted as well as flowers we would be able to see better observations or differences.

Our last test was the number of leaves on each plant. We think that environment should have an influence on the number of leaves. The results were:

wild type HL HF: avg. 7.1

wild type HL LF: avg. 8

We thought environment would have an influence but it didn't.

wild type LL LF: avg. 5.5

petite LL LF: avg. 8.5

Looking at these findings we think the genome does have an affect on the number of leaves on a plant.

Catrina Mueller's picture

Rachel Mabe and Catrina Mueller

The first thing that we observed was the height of the plants. It's largely affected by genes (hense the names "standard" and "petite"). They also seem to vary due to environmental factors. For both sets of plants, we noticed that the plants with the lower amount of light, but higher amount of fertilizer were the tallest, high light/high fertilizer was the second tallest, low light/ low fertilizer was third, and high light, low fertilizer was the shortest.

The plants with more light tended to be shorter, but had more flowers. Even with different amounts of fertilizer, high light plants had more flowers than their counterparts. We concluded that environment is the main factor in the flower.

The flowers were more clustered when the plant had the higher amount of fertilizer for both sets of plants.

For the standard group, these are the numbers of petiolar trichomes (we only took one leaf from one of each of these plants):

High light, high fertilizer- 18

Low light, high fertilizer- 15

High light, low fertilizer- 10

Low light, low fertilizer- 10

 

The only petite group plant that had these tricomes were the low light, low fertilizer plants. The leaf we looked at had 11 petiolar trichomes.

We were really baffled by the fact that only one set of plants for the petites had these "hairs". The rest seemed to be completely "bald" of these hairs.

Ruth Goodlaxson's picture

Samooble, Rutz, Pagina


Today in lab we looked at two different sets of plants, one "standard" and one "petite." We wanted to discover what factors were influenced by genes, which were influenced by the environment, and if there were any effected by both. Our findings indicated the following:

Height is effected by both genetics and the environment. Stardard plants were consistently taller than petite plants. However, the height varied between the standard plants based on their conditions.

Leaf color is a characteristic purely effected by the environment. We looked at the petite and the standard plants in high light and low fertilizer and discovered that they both had purple leaves at the bottom. Low fertilizer, low light plants also had purple stems, but none of the standard or petite plants that weren't in low fertilizer had purple.

Finally, we counted the petiolar trichromes and discovered that they are a purely genetic trait. They existed solely on standard plants, regardless of conditions, and not at all on petite plants. The number of hairs on the standard plants is as follows:

High light low fertilizer: 6

High light high fertilizer: 14

Low light high fertilizer: 5

Low light low fertilizer: 8

 

From this, we can see that while the presence of hairs is genetic the number of hairs is effected by the environment.

Jen's picture

Jen Bonczar, Kyree Harmon,

Jen Bonczar, Kyree Harmon, Marie Sager

In this lab, we first compared characteristics in genetically different but environmentally same plants in order to determine if certain characteristics were affected by the genes. We then compared characteristics in genetically same but environmentally different plants in order to determine if certain characteristics were affected by the environment. The characteristics we compared were height and stalk thickness.

Plants by number:

 

1. low light high fertilizer standard

 9 petiolar trichomes on stem.

2. Low fertilizer low light standard
19 petiolar trichomes

3. low light high fertilizer petite

no petiolar trichomes

4. low light low fertilizer petite; no petiolar trichomes

5. high light high fertilizer standard

 No petiolar trichomes

6. high light low fertilizer standard
Count of 24 petiolar trichomes on one stem.

7. high light high fertilizer petite

1 petiolar trichome

8. highlight low fertilizer petite

2 petiolar trichomes

 

Genetic differences:

 

5 and 7: environmentally identical but genetically different; maximum height is affected by genes because they were reared in the exact same environment but for some reason heights are different

 

stalk thickness is the same; perhaps not affected by genes

 

5: 18 cm tall

7: 12 cm tall

 

6 and 8: environmentally identical but genetically different; maximum height is affected by genes because they were reared in the exact same environment but for some reason heights are different

 

6: 10 cm tall

8: 3 cm tall

 

stalk thickness is the same; perhaps not affected by genes

 

Environment differences:

 

4 and 7: genetically same but environmentally different; dramatic difference in height; implies that height is a characteristic that is influenced by both genes and the environment

 

4: 5 cm tall

7: 12 cm tall

 

4 and 7 have stalk thickness difference

 

2 and 5: genetically same but environmentally different; dramatic difference in height; implies that height is a characteristic that is influenced by both genes and the environment

 

2 and 5 have stalk thickness differences; implies that this is a function of environment

 

A summary of our observations is that height is affected by both genes and environment but stalk thickness has an enivronmental influence but not a genetic one.

randomness