Quizs Ch 22 Notes Part I Introduction to Evolution

Criticism of the Law of Acquired Characteristics

• Changes in body cells can be inherited, not just changes in DNA of gametes.

• Only genetic mutations in DNA can be passed to offspring.

• Environmental factors have no impact on genetic inheritance.

• All characteristics acquired during an organism's life are inherited.

Impact of Darwin's observations

• They led to the development of Mendelian genetics.

• They caused a paradigm shift in understanding how evolution occurs.

• They were primarily focused on the study of animal behavior.

• They confirmed the static nature of species.

Lamarck's theory

• Individuals can change

• Species are fixed and unchanging

• Natural selection is the only mechanism of evolution

• All traits are inherited from parents

Law of Acquired Characteristics

• These acquired traits, formed during an individual organism's lifetime, can be passed on to offspring, leading to population changes.

• Only genetic traits can be inherited by offspring.

• Acquired characteristics are never passed to the next generation.

• Natural selection is the only mechanism for evolution.

Criticism of Lamarck's Law of Use and Disuse

• Implies that an organism can sense its needs and change to meet them (e.g., I need to reach those leaves to survive).

• Suggests that traits acquired during an organism's lifetime can be passed to offspring.

• Indicates that all organisms evolve at the same rate regardless of environmental changes.

• States that disuse of a trait leads to its enhancement in future generations.

Variation occurs in all populations

• Variations are differences between individual organisms and are inherited

• Variations are always harmful to populations

• Variations occur only in certain species

• Variations are caused by environmental factors only

ADAPTATION

• Adaptations are based on variations that were randomly inherited.

• Adaptations are always beneficial and never harmful.

• Adaptations occur only in response to environmental changes.

• Adaptations are the result of conscious choices made by organisms.

Lamarck's Law of Use & Disuse

• In response to a change in the environment, an organism can change certain body parts during its lifetime (e.g., stretch neck).

• Organisms can only adapt to their environment through genetic mutations over generations.

• All body parts of an organism are equally affected by environmental changes.

• An organism's traits are fixed and cannot change in response to environmental factors.

Jean-Baptiste de Lamarck's contribution to evolutionary theory.

• He was the first to propose a mechanism for how life evolves, although his paradigm was incorrect.

• He discovered the theory of natural selection.

• He was the first to suggest that species do not change over time.

• He introduced the concept of genetic drift.

Our planet is home to a huge variety of organisms.

• Scientists estimate 1-5 million species of organisms are alive today.

• Scientists estimate 5-20 million species of organisms are alive today.

• Scientists estimate 20-50 million species of organisms are alive today.

• Scientists estimate 50-100 million species of organisms are alive today.