Natural Variations and Evolution Flashcards

Study Notes

Natural Variation and Evolution

Natural variation is the process by which individuals with traits better suited to the environment survive and reproduce.
Organisms that adapt effectively pass on favorable traits to their offspring, enhancing survival rates.
Genetic variation (GV) leads to differences in physical traits (phenotypes) among organisms and arises mainly from mutations.
Adaptations are traits or behaviors that have evolved through natural selection to improve survival in specific environments.

Mutation and Its Role

A mutation is a change in an organism's DNA, potentially resulting in new traits. While most mutations can be harmful, some are beneficial and contribute to evolution.
Most natural variations are genetically determined, forming the basis for evolutionary processes.

Evolution and Life Origins

Evolution involves gradual changes in species over time, influenced by natural variations and adaptations.
The origin of life is theorized to begin from a primordial soup composed of organic compounds.

Charles Darwin and Species Definition

Charles Darwin proposed theories concerning common ancestry among species, emphasizing the role of natural selection.
A species is defined as a group of similar organisms that can interbreed and produce fertile offspring.

Fossils and Their Significance

Fossils are preserved remnants or traces of ancient organisms and provide evidence of past life, showing gradual complexity from sponges to mammals over 3 billion years.
Fossils found in rocks share the same age as the rock layer, assisting in the dating of geological periods.

Structural and Developmental Similarities

Homologous structures indicate organisms share a relatively recent common ancestor, reflected in similar bone arrangements among vertebrates.
Vestigial structures are reduced or non-functional parts that no longer serve their original purpose, illustrating evolutionary changes.
Analogous structures indicate features that serve similar functions but arise independently, not from common ancestry.
All vertebrates show initial similarities during early development, such as gill slits and tails.

Resistance and Genetic Material

Antibiotic resistance in bacteria and viruses arises as they evolve and adapt, making them more difficult to eliminate with existing medications.
DNA contains the genetic information passed from parents to offspring, allowing for the assessment of how closely related different species are, such as the 98% genetic similarity between humans and chimpanzees.

Dating Fossils

Relative dating compares the age of fossils and rock layers without providing exact age, whereas absolute dating offers actual numerical ages.
Understanding evolutionary processes through fossil records and genetic analysis continues to shed light on the history of life on Earth.

Description

Explore key concepts of natural variation, genetic variation, and how organisms adapt through evolutionary processes. This flashcard quiz will help reinforce your understanding of the mechanisms that drive evolution and the survival of species. Ideal for students studying biology.