Biodiversity chapter 18

Define the scientific theory of evolution

the gradual process by which modern organisms arose from earlier, more primitive organisms through the accumulation of genetic changes in populations over time. These changes can eventually lead to the formation of new species

Population

a group of individuals of one species that live in the same geographic area at the same time

Species

a group of similar organisms that can interbreed with each other

Application of Evolution: Agriculture

evolution of pesticide resistance in insects and other pests

Application of Evolution: Medicine

rapid evolution of disease-causing bacteria and viruses

Application of Evolution: Conservation management

uses evolutionary principles of population genetics for rare and endangered species

Application of Evolution: Bioremediation

evolution of micro-organisms in polluted soils for clean-up

Aristotle

believed organisms moved toward perfection

Leonardo da Vinci

correctly recognized fossils as remains of extinct organisms

Jean-Baptiste Lamarck

proposed that acquired traits could be inherited (if you used a body part more it would enhance, less it would shrink, and this was passed on)

Charles Darwin

after his voyage on the HMS Beagle, developed the theory of evolution by natural selection, which explained how species change over time based on variation, competition, and differential survival

Alfred Russel Wallace

independently reached similar conclusions to darwin

Charles Lyell (extra)

wrote principles of geology, earth’s features developed slowly over long periods by geologic processes, varieties of plant and animals could be developed in a few generations by artificial selection

Thomas Malthus (extra)

noted there has to be strong checks (famine, disease, war) on human populations

premises of evolution by natural selection as proposed by Charles Darwin: Variation

Individuals in a population differ in traits

four premises of evolution by natural selection as proposed by Charles Darwin: Overproduction

More offspring are produced than can survive

four premises of evolution by natural selection as proposed by Charles Darwin: Limits on population growth

Resources are limited, leading to competition (predators, disease, weather)

four premises of evolution by natural selection as proposed by Charles Darwin: Differential reproductive success

Individuals with favorable traits survive and reproduce more successfully

compare the modern synthesis with Darwin’s original view of evolution

Darwin explained evolution through natural selection but did not know how traits were inherited. The modern synthesis combines Darwin’s ideas with genetics, explaining variation through mutations and gene recombination and incorporating evidence from molecular biology, paleontology, systematics, and developmental biology

summarize the evidence for evolution obtained from the fossil record-

Fossils preserved in sedimentary rock show progression from simple organisms to more complex forms over time. Transitional fossils (such as early whales and birds) document evolutionary changes and reveal relationships between modern species and their ancestors

Index fossils (extra)

organisms that existed for a relatively short geological time but were preserved as fossils in large numbers over large geographic areas

define biogeography and describe how the distribution of organisms supports evolution

biogeography is the study of the geographic distribution of organisms past and present. Species on islands resemble nearby mainland species more than those in similar environments in other parts of the world, supporting the idea of descent with modification and continental drift

Migrating birds

birds can carry seeds, insects and other organisms long distances

Oceanic rafting

floating objects such as macroalgae and driftwood transport passengers

Wind/storms

strong winds can carry small organisms aerially, or aid rafting

Comparative anatomy shows: Homologous structures

same underlying structure, different function, indicating common ancestry (hands, wings, fins, hooves)

Comparative anatomy shows: Vestigial structures

reduced or nonfunctional traits inherited from ancestors (“legs” in whales)

Comparative anatomy shows: Analogous structures

similar function but different origins, showing convergent evolution (organs which do similar jobs, but evolved separately)

Convergent evolution (extra)

sometimes similar environmental conditions result in the independent evolution of similar structures (aardvark, anteater, pangolin)

Homoplastic features (extra)

structurally similar and have similar functions, but evolved independently in distantly related organisms (homoplasy, insect wings vs bird wings)

Molecular comparisons among organisms

Darwin had fossils, biogeography, and comparative anatomy to give insight as to evolutionary processes

briefly explain how molecular biology and developmental biology provide insights into the evolutionary process

All organisms share a nearly universal genetic code, and similarities in DNA and protein sequences reflect evolutionary relationships. Developmental biology shows that similar genes (such as Hox genes and Pax6) control development across many species, indicating common ancestry

give an example of how evolutionary hypotheses are tested experimentally

Researchers Reznick and Endler studied guppies in high- and low-predation environments. When guppies were moved to low-predation habitats, they evolved larger body size and later maturity within a few generations, experimentally demonstrating natural selection in action