Evolution
Theory that species change over time
In 1859, British naturalist Charles Darwin published what article?
On the Origin of Species by Means of Natural Selection.
what two points did Darwin's article speak of?
evolution and natural selection (Those individuals with variations that make them best suited to their environment will, on average, be more likely to survive and
reproduce)
the discovery of fossils (1700s) first suggested that the Earth was what?
very old and that species could change over time.
what scientist believed that a species didn't change?
Aristotle
who was the first to propose evolution?
Lamark
What scientist suggested that an old Earth had gradually changed through slow, accumulating processes?
Lyell
Who was the first to propose natural selection?
Darwin
what are teh main two points of on the origin of species?
First, modern species have descended from common ancestors (evolution).
Second, natural selection is the mechanism of evolution.
what were darwins 4 observations and what 3 conclusions did it lead him to?
OBS 1. OVER PRODUCTION
More individuals are born
than can be supported by
the environment.
OBS 2. LIMITED RESOURCE
The amount of resources
(such as food, water,
shelter, sunlight) stays
relatively constant.
CONC 1. More offspring are born than can be supp
three important points to know about evolution?
Individuals don't evolve.
Natural selection acts on
individuals, but only
populations evolve.
Natural selection works with heritable traits.
Only genetically coded traits are subject to natural selection.
Evolution does not have a goal.
Evolution occurs i
Natural selection
Those individuals with variations that make them best suited to their environment will,
on average, be more likely to survive and
reproduce.
adaptation
the accumulation of favorable traits in a population over time.
artificial selection
Humans have been substituting our desires for natural selection for millenia, enforcing unequal reproductive success.
example of artificial selection?
dog breeds
example of natural selection today?
MRSA - Methicillin-resistant Staphylococcus aureus.
Insecticide resistant malaria mosquitoes
Herbicide resistant weeds
Peppered moths in England
myxoma virus in rabbits
Radiometric dating
Fossils can be dated using their geological position
how does carbon dating work
Living organisms incorporate carbon from the environment into their bodies
This includes carbon-12 and carbon-14 in known ratios
After it dies the carbon-12 (standard atomic mass) doesn't go away, but carbon-14 isotopes decay
Half-life is how long it take
Transitional forms
provide evidence of change within lineages.
Biogeography
is the study of the geographic distribution of species.
comparative anatomy
Comparisons of the body structures of modern organisms is
how can the fossil record, bio-geography, comparative anatomy, and bioinformatics give evidence of the evolution of past life on earth?
bio- For example, the geographic isolation of Australia accounts for the dominance of marsupial mammals.
const- Examination of animal forelimbs shows they are all constructed from similar bones.
bio inf- All life uses DNA
for genetic code. Closely related
natural selection acts on ________
individuals
only ______ evolve over time
populations
Bioinformatics
employs computational tools to process genetic data.
population
group of individuals of the same species living in the same place at the same time
What are 2 mechanisms that can cause changes in an individual's genes?
mutation and Sexual recombination:
gene pool
consists of all versions of all the genes carried by all the individuals in a population.
Micro-evolution
a generation-to-generation change in the gene pool
what leads to changes in a gene pool?
natural selection
Taken over many generations, micro-evolution can result in what?
the gradual adaptation of species to the local environment.
mutation
Random changes to DNA which can create new genes.
Sexual recombination
During the formation of sperm and eggs,
chromosomes can exchange pieces of
DNA, shuffling genes.
Darwinian fitness
is the contribution that an individual makes to the gene pool of the next generation in comparison to the contributions from other individuals.
what four mechanisms other than natural selection can also contribute to evolution in gene pools?
Genetic drift
Bottleneck and founder effect
Gene flow
Sexual selection
Genetic drift
is a change in a gene pool due to chance.
For example, genes may be lost if a few individuals die or migrate at random.
This is important in small, or isolated, populations.
Bottleneck effect
If a population is drastically reduced in numbers
Founder effect
If a few individuals migrate to a new isolated habitat
Gene flow
is the genetic exchange among populations due to migration
Sexual selection
is a form of natural selection that depends on an individual's ability to obtain a mate.
Macro-evolution
is genetic change on a large scale.
Speciation
the evolutionary formation
of new species
non-branching evolution
an ancestral population changes gradually
branching evolution
an ancestral population splits into two or
more populations
how do branching and non-branching differ
In nonbranching evolution, an ancestral population changes gradually.
In branching evolution, an ancestral population splits into two or
more populations.
how do mass extinctions affect surviving species
cause rapid species diversification
tectonic plates
The Earth's crust is composed of large tectonic plates floating atop a very hot layer of rock called the mantle
mantle
very hot layer or rock
How can novel features affect the pace of evolution?
The evolution of feathers and flight in birds is an example of how structures that serve one role can
gradually change to serve another
species
is a population that is capable of interbreeding to produce healthy, fertile offspring.
Reproductive barriers
prevent members of different species from breeding.
Graduated model of speciation
a species acquires small adaptations to its environment over millions of years.
Punctuated equilibrium model of speciation
there are periods of stasis interrupted by occasional bursts of speciation.
Allopatric speciation
may occur when a physical barrier isolates populations.
Sympatric speciation
may occur quite suddenly due to large-scale genetic changes.
Taxonomy
the identification, naming, and classification of species.
domains
life is classified into one of three large groups called domains based on cell type.
Taxonomic hierarchy
an ordered series of progressively smaller categories.
Phylogenetic tree
are one way to reflect the evolutionary history of organisms.
Phylogenetic trees present a hypothesis about the evolutionary history of related species.
How can phylogenetic trees give insight into evolutionary relationships?
Phylogenetic trees present a hypothesis about the evolutionary history of related species.
Clades
is a any group of species that consists of an ancestral species and all its descendants.
What are the 6 reproductive barriers that prevent species from successfully interbreeding?
Behavioral isolation, Mating time differences, Habitat isolation, Mechanical incompatibility, Gametic incompatibility, Hybrid weakness
What are 3 types of events that can separate a population into two species?
Time, space, or genetics
Cladistics
The analysis of clades
How have major geologic changes affected life on earth?
Geological upheavals can be catastrophic in the short term and can alter the evolution of life on Earth in the long term.
Earthquakes, mountain building, volcanoes