What is a basic requirement of a scientific hypothesis must have?

On the Galapagos islands Darwin observed tortoises with a dome and saddle shaped shells. How did Darwin observation of these tor

Nataly [62]

Hi

It is true that on the Galapagos islands Darwin observed tortoises with a dome and saddle shaped shells, you can see both in attached image.

Darwin observed that Galapagos Tortoises had the shells with different shapes depending on the Island they live, For example: The tortoises with saddle shaped shells were able to reach up to eat leaves of plants while the tortoises with dome shaped shells would not reach up and they would eat food from on ground sources. This made him think that the differences in tortoise shell is also a strong evidence that indicates that how tortoises have adapted themselves to better get their food as per the available resources and how they have evolved from same ancestral specie into two different species. This point also helped him in proposing the theory of evolution by natural selection.

Hope it helps!

5 0

3 years ago

Good things to say about the wright brothers in a presentation

Goryan [66]

Wilbur and Orville Wright were American inventors and pioneers of aviation. In 1903 the Wright brothers achieved the first powered, sustained and controlled airplane flight; they surpassed their own milestone two years later when they built and flew the first fully practical airplane.

5 0

2 years ago

What are the biggest advantages of natural gas as a fuel source?

GaryK [48]

Due to its cleaner combustion, natural gas is the most environmentally safe fossil fuel. Natural gas doesn't have as many toxic combustion byproducts as other fossil fuels.

Natural gas is adaptable. Starting and stopping a gas-fired power plant is substantially faster than one that burns coal.
Due to its flexibility, it complements renewable energy sources like solar and wind, which are only usable when the sun is out and the wind is blowing.
When burned to produce power, natural gas is the cleanest-burning hydrocarbon, releasing about half as much carbon dioxide (CO2) and only one-tenth as much air pollutants as coal.
By switching to natural gas from coal, there is a significant opportunity to cut CO2 emissions and air pollution in the near future.
Because Natural gas is now so widely accessible through LNG, it can assist nations in coping with short-term supply interruptions.

learn more about Natural gas here: brainly.com/question/4677279

#SPJ4

5 0

2 years ago

What two evidences supports the continents were once together?

Bezzdna [24]

Fossil Fuels and Continental drift support the idea that once continents were together.

Explanation:

Fossil fuels like plants, animals and rocks are of the identical features were found in the two different continents. For example, identical rocks found in the two sides of the Atlantic ocean, even the mountains in two different continents formed of the identical rocks.
The next one is fossils of the seed fern Glossopteris is found across all the southern continents. Hence, there is continental drift happened which caused the separation of continents.

5 0

3 years ago

In your experiment, you found the following offspring only:Tall green: 626 offspring.Tall yellow: 313 offspring.Short green: 309

Karo-lina-s [1.5K]

Complete question:

1. You found a new species of garden pea and have decided to repeat Mendel’s experiments. You have obtained two true-breeding pea plants that are tall (T) with yellow pods (g), and short (t) with green pods (G), respectively. Capital letters indicate dominant traits.

a. What is the genotype and phenotype of the F1 generation? (2p)

b. You allowed self-fertilization in F1 generation and obtained F2 generation. Using Punnett square to obtain the phenotypes, genotypes and their respective ratios. (4p)

2. If you obtained 1248 offspring in the F2 generation in Question 1, calculate how many offspring of each phenotypic class you would expect to have. (4p)

3. When you finish questions 1 and 2, under what assumption/hypothesis did you perform your analysis/calculation? Is there an alternative assumption/hypothesis, which may result in a different conclusion? If yes, what is the alternative assumption/hypothesis and what kind of offspring and in what numbers do you expect to obtain? (4p)

4. You only need to answer A or B to get this 6p. Please indicate which question you are answering. In your experiment, you found the following offspring only: Tall green: 626 offspring. Tall yellow: 313 offspring. Short green: 309 offspring.

A: If you stay with your original hypothesis/assumption, test it using chi2 test and analyze the result (whether you want to reject the hypothesis and why).

B: If you believe that the alternative hypothesis fits better with your data, test it using chi2 test and analyze the result (whether you want to accept the hypothesis and why).

Answer:

1) a. 100% of the progeny will be dihybrid, TtGg, exhibiting the phenotype

Tall plants with green pods.

b. F2 Gentotype:

1/16 TTGG
2/16 TTGg
1/16 TTgg
2/16 TtGG
4/16 TtGg
2/16 Ttgg
1/16 ttGG
2/16 ttGg
1/6 ttgg

F2 Phenotype:

9/16 Tall plants with green pods (T-G-)
3/16 Tall plants with yellow pods (T-gg)
3/16 Short plants with green pods (ttG-)
1/16 Short plants with yellow pods (ttgg)

Phenotypic ratio → 9:3:3:1

2) T-G- → 702 individuals

T-gg → 234 individuals

ttG- → 234 individuals

ttgg → 78 individuals

3)

Null Hypothesis: The population is under Hardy-Weinberg equilibrium. The alleles of this population assort independently.

Alternative Hypothesis: The population is not in equilibrium. Alleles do not assort independently.

4) a. There is enough evidence to reject the null hypothesis, meaning that the difference between the observed number of individuals and the expected ones is statistically significant. The population is not under equilibrium H-W. Alleles do not assort independently.

Explanation:

1) 1st Cross: True-breeding tall (T) with yellow pods (g) pea plant with a short (t) with green pods (G) plant

Tall and Green pods are the dominant traits,
Short and yellow pods are recessive traits.

Parentals) TTgg x ttGG

Gametes) Tg, Tg, Tg, Tg tG, tG, tG, tG

F1) 100% of the progeny will be dihybrid, TtGg, exhibiting the phenotype

Tall plants with green pods.

2nd Cross: F1 self-fertilization

Parentals) TtGg x TtGg

Gametes) TG, Tg, tG, tg

TG, Tg, tG, tg

Punnett square) TG Tg tG tg

TG TTGG TTGg TtGG TtGg

Tg TTGg TTgg TtGg Ttgg

tG TtGG TtGg ttGG ttGg

tg TtGg Ttgg ttGg ttgg

F2) Gentotype:

1/16 TTGG
2/16 TTGg
1/16 TTgg
2/16 TtGG
4/16 TtGg
2/16 Ttgg
1/16 ttGG
2/16 ttGg
1/6 ttgg

Phenotype:

9/16 Tall plants with green pods (T-G-)
3/16 Tall plants with yellow pods (T-gg)
3/16 Short plants with green pods (ttG-)
1/16 Short plants with yellow pods (ttgg)

Phenotypic ratio → 9:3:3:1

2) The total number of individuals in the F2 is 1248.

16 ----------------- 1248 individuals --------------- 100% of the progeny

9 T-G- ----------- X = 702 individuals-------------X = 56.25%

3 T-gg ----------- X = 234 individuals ----------- X = 18.75%

3 ttG- ------------- X = 234 individuals ---------- X = 18.75%

1 ttgg ------------- X = 78 individuals ------------ X = 6.25%

3)

Hypothesis: The population is under Hardy-Weinberg equilibrium. The alleles of this population assort independently.

Alternative Hypothesis: The population is not in equilibrium. Alleles do not assort independently

4) F2 composed of:

Tall green: 626 offspring.
Tall yellow: 313 offspring.
Short green: 309 offspring.

Tall/Green Tall/Yellow Short/Green Short/Yellow

Observed 626 313 309 0

Expected 702 234 234 78

(Obs-Exp)²/Exp 8.23 26.7 24 78

X² = Σ(Obs-Exp)²/Exp = 8.23 + 23.7 + 24 + 78 = 136.93 ≅ 137

Freedom degrees = genotypes - number of alleles = 9 - 4 = 5

Significance level, 5% = 0.05

Table value/ Critical value = 11.07

X² = 137

X² > Critica value

137 > 11.07

There is enough evidence to reject the null hypothesis, meaning that the difference between the observed number of individuals and the expected ones is statistically significant. The population is not under equilibrium H-W. Alleles do not assort independently.

5 0

3 years ago