ENVS 1100 Lecture Notes - Lecture 16: Global Warming, Habitat Fragmentation, Habitat Destruction
3 May 2018
School
Department
Course
Professor
Evolution
October 9, 2014
Invasive Species – non-native species whose introduction causes or is likely to
cause economic or environmental harm
Extinction – the complete loss of a species from an area (local/global)
Evolution is the change over time. Differences in gene frequencies from one
generation to the next is the definition of evolution.
Biological evolution is genetic changes in organisms across generations. This
includes changes in appearance, functioning and behavior
Coevolution – two species each provide the selective pressure that determines
which traits are favoured by natural selection in the other
Evolution by natural selection is a process in which traits enhance the survival and
reproduction are passed on more frequently to future generations than those traits
that do not. Natural selection causes organisms that are best adapted to the
environment (the fittest) to pass on their traits to future generations.
Selective Pressures – nonrandom influence affected who survives and reproduces
Genes – distinct pieces of DNA that determine characteristics an individual displays
Population – considered to be all organisms…
Gene Frequencies – assortment and abundance of particular variants of genes
relative to each other within a population
Genetic Diversity – heritable variation among individuals of a single population
within the species as a whole
Genetic Drift – change in gene frequencies of a population over time due to random
mating that results in the loss of some gene variants
Bottleneck Effect – when population size is drastically reduced, leading to the loss
of some genetic variants (population is less diverse)
Founder Effect – when a small group with only a subset of the larger population’s
genetic diversity becomes isolated and it evolves into a different population
(missing some traits)
Charles Darwin’s Theory of Natural Selection:
Some individuals will be better suited….
Adaptation
• Trait that helps an individual survive or reproduce
Survival is only half the story- you have to reproduce to mass on good traits that aid
survival.
Individuals are selected for, but populations evolve.
Individuals do not necessarily change their own genetic makeup.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
October 9, 2014 cause economic or environmental harm. Invasive species non-native species whose introduction causes or is likely to. Extinction the complete loss of a species from an area (local/global) Coevolution two species each provide the selective pressure that determines. Differences in gene frequencies from one generation to the next is the definition of evolution. Biological evolution is genetic changes in organisms across generations. This includes changes in appearance, functioning and behavior which traits are favoured by natural selection in the other. Evolution by natural selection is a process in which traits enhance the survival and reproduction are passed on more frequently to future generations than those traits that do not. Natural selection causes organisms that are best adapted to the environment (the fittest) to pass on their traits to future generations. Selective pressures nonrandom influence affected who survives and reproduces. Genes distinct pieces of dna that determine characteristics an individual displays.
