Evolution and Speciation Overview

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Questions and Answers

What role does the environment play in natural selection?

It provides nutrients for survival.

It has no impact on survival.

It selects individuals that are more fit to survive. (correct)

It mainly affects reproduction rates.

Which statement best defines mutation?

An alteration in DNA sequence due to environmental factors.

A process where two species interbreed.

A form of natural selection leading to better fitness.

A copying error in DNA during cell division. (correct)

What is gene flow?

A form of natural selection that enhances species' traits.

The transfer of genetic material between populations. (correct)

The avoidance of reproduction between two species.

The process by which species become extinct.

Which type of reproductive isolation occurs due to physical barriers?

Geographical Isolation Signup and view all the answers

What is the result of a population bottleneck?

A significant decrease in population size. Signup and view all the answers

Which form of reproductive isolation is characterized by different mating rituals?

Behavioral Isolation Signup and view all the answers

Temporal isolation prevents species from mating because:

They breed at different times. Signup and view all the answers

What term describes the phenomenon where 'survival of the lucky ones' occurs after a population experiences a drastic decrease?

Genetic Drift Signup and view all the answers

What characterizes organisms belonging to the same species?

They are able to interbreed and produce fertile offspring. Signup and view all the answers

What is the definition of speciation?

The evolution of new species. Signup and view all the answers

Which of the following is NOT considered a factor responsible for speciation?

Food availability Signup and view all the answers

What is the significance of sterile hybrids like mules and ligers in relation to species classification?

They illustrate that hybrids are not classified as part of either parent species. Signup and view all the answers

Which genetic difference between chimpanzees and humans is mentioned?

1.2% Signup and view all the answers

Which of the following best describes 'genetic drift'?

Random changes in allele frequencies in a population. Signup and view all the answers

Why can two organisms of different species not interbreed successfully?

They have a significant genetic difference. Signup and view all the answers

What role does reproductive isolation play in speciation?

It prevents different species from mating and producing fertile offspring. Signup and view all the answers

Which of the following best defines an ecosystem?

A chain of interaction between organisms and their environment. Signup and view all the answers

What is the primary difference between climate and weather?

Climate averages conditions over time; weather describes short-term events. Signup and view all the answers

Which climate type is characterized by extremely cold temperatures and summers that rarely exceed 50°F (10°C)?

Polar Signup and view all the answers

What is meant by the term biodiversity?

The variety of life forms in a specific environment. Signup and view all the answers

Which of the following steps is NOT part of the operation of an ecosystem?

Permanent storage of organic materials in consumers. Signup and view all the answers

Which climate type typically experiences warm summers with mild winters and occasional thunderstorms?

Temperate Signup and view all the answers

In which type of ecosystem do organisms primarily interact with water bodies?

Aquatic Ecosystem Signup and view all the answers

What role do decomposers play in an ecosystem?

They degrade complex organic compounds for reuse. Signup and view all the answers

What is genetic diversity primarily concerned with?

The range of different genes within species Signup and view all the answers

Which level of biodiversity includes all the different habitats and ecological processes?

Ecosystem diversity Signup and view all the answers

What percentage of the world’s plants and animal species can be found in the Philippines?

70% Signup and view all the answers

Species diversity refers to what aspect of biodiversity?

The variety of species present in an ecosystem Signup and view all the answers

The interrelatedness of genes, species, and ecosystems is a concept of which aspect of biodiversity?

Ecological interdependence Signup and view all the answers

Why does the Philippines have such a high level of biodiversity?

Its geographic isolation Signup and view all the answers

Which aspect of biodiversity focuses on the variety and abundance of species?

Species diversity Signup and view all the answers

Which of the following does not contribute to ecosystem diversity?

Genetic variation among species Signup and view all the answers

Ecosystem diversity includes which of the following characteristics?

Diversity of ecological processes Signup and view all the answers

What is the largest contributor to the richness of biodiversity in a specific region?

Geographic isolation of the area Signup and view all the answers

Study Notes

Evolution

Evolution is the process by which living organisms developed and diversified from earlier forms.
A species is a group of organisms that share a close genetic heritage, can interbreed, and produce fertile offspring.
If two organisms can produce fertile offspring, they are considered the same species, for example, two humans can produce children as human DNA is similar.
If two organisms cannot produce fertile offspring, they are considered different species, for example, humans and chimpanzees are different species as their DNA is different by 1.2% to 1.6%.
A mule, a hybrid of a horse and a donkey, is sterile, proving that horses and donkeys are different species.
A liger, a hybrid of a lion and tiger, is sterile, proving that lions and tigers are different species.

Speciation

Speciation is the evolution of new species.
Factors responsible for speciation include:
- Natural Selection: "Survival of the fittest", environment favors individuals best suited to survive and reproduce.
- Mutation: A change in the DNA sequence, can be caused by cell division errors, radiation, chemical exposure, or viral infection.
- Gene Flow: Transfer of genetic material from one population to another. Continued gene flow prevents populations from becoming distinct, while cessation of gene flow promotes speciation.
- Reproductive Isolation: Inability or unwillingness to interbreed, leading to speciation. Types of isolation include:
  - Geographical Isolation: Physical barriers prevent interbreeding.
  - Habitat Isolation: Species occupy different environments within the same geographic area, preventing interbreeding.
  - Behavioral Isolation: Species develop different mating rituals, leading to non-recognition or lack of preference between populations.
  - Temporal Isolation: Species breed at different times, preventing interbreeding.
- Genetic Drift: "Survival of the lucky ones", commonly occurs after a population bottleneck causing a drastic decrease in population size.

Environment

The place or surroundings where organisms live, adapt and interact for survival.

Climate

The average weather in a given area over a longer period of time.

Types of Climates

Tropic: Hot and humid.
Dry: Little precipitation, moisture evaporates quickly.
Temperate: Warm and humid summers with thunderstorms, mild winters.
Continental: Warm to cool summers, very cold winters with possible snowstorms, strong winds, and temperatures below freezing.
Polar: Extremely cold year-round, temperatures never reaching 50°F (10°C) even in summer.

Ecosystems

An aspect of the environment where living organisms interact with each other and the surrounding environment.
A chain of interaction between organisms and their environment.

Types of Ecosystems

Terrestrial Ecosystem: land-based ecosystems.
Aquatic Ecosystem: water-based ecosystems.

Structure of an Ecosystem

Terrestrial Ecosystem: Composed of producers (plants), consumers (animals), and decomposers (bacteria and fungi).
Aquatic Ecosystem: Composed of producers (algae), consumers (fish, invertebrates), and decomposers (bacteria and fungi).

Biodiversity

Biological diversity, referring to the vast variety of life on Earth.
More specifically, it can refer to the species in a region or ecosystem.
Encompasses the interrelatedness of genes, species, and ecosystems and their interactions with the environment.

3 Levels of Biodiversity

Genetic Diversity: Diversity of genes within a species.
Species Diversity: Number of species within an ecosystem or the entirety of the biosphere.
Ecosystem Diversity: Variation in habitats, biological communities, ecological processes, and diversity within individual ecosystems.

Philippine Biodiversity

The Philippines contains 2/3 of the Earth's biodiversity and 70% of the world's plants and animal species due to its geographic isolation.

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Description

Explore the fascinating processes of evolution and speciation. Understand how species are defined, the importance of genetic heritage, and the factors driving the emergence of new species. Juxtapose examples such as mules and ligers to appreciate the concept of species differentiation.