homologous structures are similar structures in different organisms that have a common evolutionary origin an example is

ATI TEAS 7

TEAS Test 7 science

1. Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:

A. Butterfly wings and bird wings (analogous structures with different origins)
B. The arm of a human, the wing of a bat, and the flipper of a whale
C. The eyes of an octopus and a human (convergent evolution with different origins)
D. The stinger of a bee and the barb of a cactus (unrelated structures)

Correct answer: B

Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. The arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions, they share a common underlying structure due to their evolutionary relationship, evidencing a shared ancestry. These structures are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures with different origins. Option C (The eyes of an octopus and a human) describes convergent evolution where traits evolve independently. Option D (The stinger of a bee and the barb of a cactus) are unrelated structures.

2. Which bones are included in the axial skeleton?

A. Head, neck, and trunk
B. Arms and legs
C. Hands and feet
D. All of the above

Correct answer: A

Rationale: The correct answer is A: Head, neck, and trunk. The axial skeleton comprises bones located in the head, neck, and trunk region, such as the skull, vertebral column, and rib cage. These bones provide structural support and protect vital organs like the brain, spinal cord, and heart. Choices B and C are incorrect because arms, legs, hands, and feet are part of the appendicular skeleton, not the axial skeleton. The appendicular skeleton is responsible for movement, manipulation, and mobility, while the axial skeleton primarily provides central support and protection for essential organs.

3. With which genotype would the recessive phenotype appear if the dominant allele is marked with 'A' and the recessive allele is marked with 'a'?

A. AA
B. aa
C. Aa
D. aA

Correct answer: B

Rationale: The recessive phenotype appears when an individual has two copies of the recessive allele. In this case, the recessive allele is marked with 'a.' Therefore, the genotype 'aa' would display the recessive phenotype as both alleles are recessive. Choice A (AA) has two dominant alleles, choice C (Aa) has one dominant and one recessive allele, and choice D (aA) represents the same genotype as Aa due to the principle of allele dominance.

4. Which of the following statements is FALSE?

A. An organelle is a specialized structure in a cell, such as a ribosome.
B. An organ is made up of different types of tissues that work together to perform specific functions.
C. Organ systems are two or more organs performing similar functions.
D. A tissue contains a variety of cells that work together to perform a specific function.

Correct answer: B

Rationale: The statement provided in Option B is FALSE. Organs are actually made up of different types of tissues that work together to perform specific functions, rather than being composed of similar tissues. Organs consist of various tissues, each with their own specialized functions that collectively contribute to the overall function of the organ. Options A, C, and D are true statements. Option A correctly defines an organelle as a specialized structure in a cell, like a ribosome. Option C accurately describes organ systems as multiple organs working together to perform related functions. Option D correctly explains that a tissue is composed of different cells working together to carry out a specific function.

5. During exercise, heart rate increases to deliver more oxygen to the body's tissues. What other cardiovascular response also increases?

A. Blood pressure decreases
B. Blood vessel diameter narrows
C. Blood flow to muscles increases
D. Blood viscosity thickens

Correct answer: C

Rationale: During exercise, the cardiovascular response includes an increase in blood flow to the muscles to deliver more oxygen and nutrients needed for energy production. This helps to support the increased demand for oxygen and nutrients by the working muscles. Blood pressure typically increases during exercise to help facilitate this increased blood flow to the muscles. Additionally, blood vessel diameter may widen (vasodilation) to allow for more blood flow, rather than narrow. Blood viscosity does not typically thicken during exercise.