CH 22: An Introduction to Evolution

BIO 1134

Earth’s biodiversity is organized into _____ domains and unified by the process of evolution.

3 domains

• domain bacteria

• domain archaea

• domain eukarya

Jean Baptiste Lamarck - mechanisms of evolution

• (1744-1829)

• a naturalist with a philosophical approach

  • tries to understand the world using logic, reasoning and big ideas

  • popularized the view that species change over the course of many generations by adapting to new environment

• First model of evolution (1809)

• Inheritance of acquired characteristics

  • proposed that organisms may alter their behavior in response to environmental changes and further hypothesized that behavioral changes could modify traits and these modified traits could be inherited by offspring

  • Ex: believed giraffes developed their long necks and front legs by feeding on leaves at the top of trees and having to exercise stretching up to leaves, altering the neck and legs

• First model which was the inheritance of acquired characteristics was the mechanism for evolutionary change

Charles Darwin - mechanisms of evolution

• (1809-1882)

• a naturalist with an empirical approach

  • uses data and experiments to explain nature

  • believed that existing species have evolved from pre-existing ones

• created the second model of evolution

• natural selection

True or False: Charles Darwin’s influence on biology began in the mid-1800s and continues today.

True

Charles Darwin and Alfred Wallace history of our understanding of evolution.

• The work of many geologists and naturalists influenced the work of both Charles Darwin and Alfred Wallace

  • through others works they learned that Earth was very, very old and dynamic

  • earth now is the product of time and many, many geologic, atmospheric, chemical, and biological changes

Charles Darwin Voyage of the H.M.S Beagle

• (1831-1836) - Darwin was 22 years old in 1831

• 5 year around-the-world surveying voyage examining different species and record information about the weather, geological features, plants, animals, fossils, rocks, minerals, and indigenous people

• struck by the diversity of life on the Galapagos Islands, west of South America, which included many species found nowhere but on one of the islands

• Gave him the opportunity to compare species of older continents to their counterparts on younger islands

• His comparisons of species between South America and the Galapagos Islands were the most influential to his development of the theory of evolution

• saw lizards and tortoises and birds where he observed their different becks in relation to eating habits

Alfred Wallace

• (1823-1913)

• Created On the Law Which Has Regulated the Introduction of New Species (1855)

  • developed a theory of evolution by natural selection essentially identical to Darwin’s

  • not as widely known as Charles Darwin’s

  • asked Darwin’s opinion of his work in June 1858

  • decided to join forces with Darwin with same theories

• Wallace traveled and studied species in Africa, Asia, and South America

Charles Darwin - On the Origin of Species

• Charles Darwin understood artificial selection (human selection of desired phenotypes in domesticated crops) and questioned if the environment could do the same “selecting”

  • this is the basis of natural selection

• Published On the Origin of Species by Means of Natural Selection in 1859

  • did not use the term evolution but instead descent with modification

  • claimed natural selection as the mechanism of evolution

Descent with modification

is the evolution of species from ancestral species as changes accumulate over time

• ex: birds and their beaks

Evolution

• change over time

• species evolve from ancestral species as changes accumulate over time

Natural selection

• occurs from the interactions of the environment and the inherent variability in a population

• is differential reproductive success that results from interactions between heritable variation in a population and the environment

Artificial selection to natural selection

• Artificial selection shows us that populations can change over time when certain traits are chosen

• Natural selection is the same process—just with nature doing the choosing instead of humans.

Evidence of Biological Evolution

• The Grant’s research with Galapagos finches is evidence of evolution by natural selection

Evidence for Biological Evolution types

1. Studies of natural selection

2. Selective breeding (artificial selection)

3. Biogeography

4. Convergent evolution

5. Fossil records

6. Homologies

   1. anatomical

   2. developmental

   3. molecular

What else also contributes to the evolution of species?

Horizontal Gene Transfer

• mechanisms of biological evolution

  • vertical descent with mutation

  • horizontal gene transfer

How does antibiotic resistance develop in a strain of bacteria?

Gene transfer, mutations, and natural selection produce bacterial strains resistant to antibiotics