General Biology II (Part II)

Question 1

is a powerful and important process. It is a process which, over billions of years, gradually selects the organisms that are better adapted to their environment to continuously change life and make all living organisms in our world the way they are today.

Answer 1

Biological Evolution

Question 2

is not a finished event wherein humans are the final product.

Answer 2

Evolution

Question 3

Rather, it is a continuing process which has been changing and forming life on Earth for billions of years, and continues to do so for as long as organisms are born, dying and competing for what they need to survive and reproduce.

Answer 3

Evolution

Question 4

“Species are groups of interbreeding natural populations that are reproductively isolated from other such groups.”

Answer 4

Species - Ernst Mayer’s definition

Question 5

The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation.

Answer 5

Reproductive Isolating Mechanism

Question 6

They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.

Answer 6

Reproductive Isolating Mechanism

Question 7

2 Types of Reproductive Isolating Mechanism

Answer 7

Pre- Zygotic Isolation Mechanisms
Post- Zygotic Isolation Mechanisms

Question 8

• prevents fertilization and zygote formation

Answer 8

Pre-zygotic isolation mechanisms

Question 9

• happens before fertilization occurs between gametes

Answer 9

Pre-zygotic isolation mechanisms

Question 10

5 types of Pre- Zygotic Isolation Mechanisms

Answer 10

• Geographic or Ecological or Habitat Isolation
• Temporal or Seasonal Isolation
• Behavioral Isolation
• Mechanical Isolation
• Gametic Isolation

Question 11

3 Types of Post- Zygotic Isolation Mechanisms

Answer 11

• Hybrid Inviability
• Hybrid Sterility
• Hybrid Breakdown

Question 12

is the evolutionary process by which populations evolve to become distinct species. It is the process by which new species develop from existing species.

Answer 12

Speciation

Question 13

3 Mode of Speciation

Answer 13

Allopatric Speciation
Sympatric Speciation
Parapatric Speciation

Question 14

• occurs when two species that could interbreed do not because the species live in different areas. The two species live in different habitats and will not encounter one another: each is isolated from the other species.

Answer 14

Geographic or ecological or habitat isolation

Question 15

• different groups may not be reproductively mature. For example, two populations of plants may produce flowers in different seasons, making mating between the populations impossible.

Answer 15

Temporal or seasonal isolation

Question 16

patterns of courtship is different.

Answer 16

Behavioral isolation

Question 17

• differences in reproductive organs prevent successful interbreeding.

Answer 17

Mechanical isolation

Question 18

• incompatibilities between egg and sperm prevent fertilization. Often this occurs because the female immune system recognizes sperm as foreign and attacks it.

Answer 18

Gametic isolation

Question 19

• fertilized egg fails to develop past the early embryonic stages.

Answer 19

Hybrid inviability

Question 20

• their hybrids are ________ because gonads develop abnormally or there is abnormal segregation of chromosomes during meiosis.

Answer 20

Hybrid sterility

Question 21

• F1 hybrids are normal, vigorous and viable, but F2 contains many weak or sterile individuals

Answer 21

Hybrid breakdown

Question 22

______________ or geographic speciation occurs when some members of a population become geographically separated from the other members thereby preventing gene flow.

Answer 22

Allopatric speciation

Question 23

occurs when members of a population that initially occupy the same habitat within the same range diverge into two or more different species

Answer 23

Sympatric Speciation

Question 24

occurs when the groups that evolved to be separate species are geographic neighbors. Gene flow occurs but with great distances is reduced.

Answer 24

Parapatric Speciation