Chapter 4 Terms
Evolution and Biodiversity
EV: To understand to role of biodiversity through evolution: Change over time
Directions: Students must define all Chapter 4 terms and submit for grade. Students will retain their
definitions once they have been checked for completeness. These terms are vital for student
understanding of the concepts that will be discussed in the chapter.
Biological evolution
Tectonic plates
Natural selection
Ecological niches/niche
Scientific theory
Fundamental niche
Chemical evolution
Realized niche
Fossils
Generalist species
Fossil record
Specialist species
Mutations
Specialization
Natural selection
Geographic isolation
Genetic variability
Reproductive isolation
Differential reproduction
Extinction
Adaptation/adaptive traits
Endemic species
Coevolution
Background extinction
Hybridization
Mass extinction
Horizontal gene transfer
Mass depletion
“survival of the fittest”/”survival of the strongest”
Artificial selection
Genetic engineering/gene splicing
Recombinant DNA
Genetically modified organisms (GMO’s)
Transgenetic organisms
Topics of discussion:
1) Origins of Life
 Scientific evidence indicates that the earth’s life is the result of about 1 billion years of
chemical change to form the first cells, followed by about 3.7 billion years of biological
change to produce the variety of species we find on the earth today.
 Biological evolution
 Natural selection
 Fossils: How do we know which organisms lived in the past?
2) Evolution, natural selection, and adaptation
a. Genetic mutations: changes in the population gene pool……biological evolution by natural
selection involve the change in a population’s genetic makeup through successive
generation (NOTE: populations change, not individuals-evolve by becoming genetically
different.
b. Mutations: genetic variability…..beneficial?
c. Natural selection and adaptation: genetically based traits that increase their chances of
survival and their ability to produce offspring with the same traits.
d. Genetic variability,, heritability, differential reproduction
e. Adaptation or adaptive trait-heritable trait that enables an organism to survive through
natural selection and reproduce better under prevailing environmental conditions.
Natural selection tends to preserve beneficial adaptations in populations and discard
harmful ones.
f. Hybridization and gene swapping: other ways to exchange genes.
i. Horizontal gene transfer….hybridization and gene transfers and the resulting
adaptations can occur rapidly compared to the thousands to millions of years
required for the conventional Darwinian evolution of sexually reproducing species
through natural selection.
g. Limits on adaptation through natural selection
i. 1st-a change in environmental conditions can lead to adaptation through conventional
natural selection only for genetic traits already present in a population’s gene pool.
ii. 2nd-if a beneficial heritable trait is present in a population, the population’s ability
to adapt may be limited by its reproductive capacity
iii. Common myths about evolution through natural selection..
h. Common myths about evolution through Natural selection
i. Evolution through natural selection is about leaving the most descendants:
organisms do not develop certain traits because they need them or want them: and
there is no master plan leading to genetic perfection
1. Three common misperceptions
a. “survival of the fittest” – means “survival of the strongest”…..fitness
is a measure of reproductive success, not strength. Thus, the fittest
are those that leave the most descendants.
b. Organism develop certain traits because they need or want them.
The gene for the giraffe to have a long neck was passes from an
ancestor, therefore the giraffe passes down that gene to offspring.
c. Evolution by natural selection involves some grand plan of nature in
which species become more perfectly adapted. NO PLAN OR GOAL
OF GENETIC PERFECTION HAS BEE IDENTIFIED IN THE
EVOLUTIOANARY PROCESS.
Thinking question: Do you accept or reject the scientific theory of biological evolution by natural
selection? If you reject, what specific mechanism do you believe can account for the variety of life on
the earth and what is the accepted and peer-reviewed scientific evidence for such a mechanism.
3) Geologic processes, climate change, catastrophes and evolution
The very slow movement of huge solid plates making up the earth’s surface, volcanic eruptions,
and earthquakes can wipe out existing species and help form new ones.
a. Tectonic plates-how has the earth’s surface changed over its long history
b. Climate change and natural selection
c. Catastrophes and natural selection
4) Ecological niches and adaptation
a. Ecological niches: how species live and coexist
i. Ecological niche
ii. Fundamental niche
iii. Realized niche
b. Generalist and specialist species: Broad and narrow niches
i. Generalist species
ii. Specialist species
5) Speciation, extinction, and biodiversity
a. How do species evolve? A new species can arise when members of population are isolated
from other members for so long that changes in their genetic makeup prevent them from
producing fertile offspring if they get together again.
b. speciation
c. geographic isolation
d. reproductive isolation
e. extinction
i. endemic species- species that are found only in one area and are especially
vulnerable to extinction…..they exist only on islands and other unique small areas
f. background extinction, mass extinction and mass depletion
i. background extinction
ii. mass extinction
iii. mass depletion
g. Effects of human activities on the earth’s biodiversity: Are we a wise species?
6) Genetic engineering and the future of evolution