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Natural Selection and the Origin of Species
Name:
Jean-Baptiste Lamarck (1744-1829)
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Realized that species changed over time
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Inheritance of ________________characteristics
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Parents pass on traits that they get during their lives
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Ex. Giraffes stretching to reach food led to longer necks, and these were passed on to offspring
We know it is __________________________________
Thomas ________________ (1766-1834)
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Determined that populations grow exponentially, while resources grow arithmetically
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Production cannot keep up with population growth
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Point of crisis
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A.K.A. ________________________________
Charles ________________ (1797-1875)
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Geologist
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Came up with the idea (new at the time) that the Earth had always gone through similar geologic changes as happen
today (________________________________)
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Continental drift, volcanism, etc.
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Before this, it was thought that the Earth did not often change, except for times of catastrophes (i.e.
Earthquakes and Volcanic eruptions were rare and only destroyed things)
Also discovered the Earth was older than thought in the day
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Most people thought the Earth was no more than 10,000 years old
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Lyell’s work pushed that back to several million years
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Later findings eventually pushed that back to ________________________________
Artificial Selection
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________________make gradual changes to species to get organisms we want through encouraging breeding of those
with desired traits
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Also known as ________________________________
Sexual Selection
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Some species have traits designed to ________________________________
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Often, these traits are detrimental to the organism, as they require a lot of energy or make them stand out
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Ex. Birds building complicated nests and singing and dancing to attract a mate
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Or, peacocks displaying intricate tail feathers to attract a mate.
In these cases, the organism is putting itself in danger to attract a mate
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However, if they are successful, they ________________________________________________
Charles ________________ (1809-1882)
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English naturalist
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HMS ________________
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Chart the coastline of South America
Fascinated by the different plant and animals he saw
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Collected extant organisms, and fossils of extinct organisms
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Some organisms looked like variants of ones in other areas
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Including those in his native England
________________________________Islands
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Lots of interesting organisms
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Different organisms on different islands or in South America had similar traits.
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Turtles on the islands varied
Darwin’s ________________________________
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Birds on different islands
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Different appearance, food sources, and songs
All were finches.
Darwin’s Conclusions
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Based on the science of the day, and his own observations, Darwin came up with 4 conclusions that led to his theory
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Organisms ________________________________________________is higher than an environment can support
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Individuals within a species ________________________________________________________________
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Traits are passed from ________________________________________________________________
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Individuals with traits that are ________________________________to their environment are more likely to
________________________________________________, passing these traits on to their offspring
Darwin’s Theory of Natural Selection
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Recall that a Theory in science is NOT A GUESS!
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It is an ________________________________for natural phenomena
Theory of Natural Selection
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________________________________for survival the organisms best suited to survive there.
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I.E. If an organism is better able to survive where it lives, it survives. If it is not, it does not.
Sometimes referred to as “________________________________________________”
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Biological Definition of Fitness
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The ability to ________________________________in a given environment
Variation and Adaptation
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Variations are ________________________________________________________________________________
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Examples: ________________________________________________________________________________
Adaptations are variations that _________________________________________________________________________
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Examples: ________________________________________________________________________________
Adaptations
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________________________________are central to Natural Selection
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Variations that are beneficial are selected for
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________________-blending in with surroundings to keep from being spotted
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________________-looking like something dangerous, which makes predators afraid
Gives them an advantage over other members of their species
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They are more likely to survive and pass the trait on
If it is not beneficial, it is not an adaptation!v
Hardy-Weinberg Principle
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States that the allele frequency in a population will remain constant from generation to generation in the absence of
evolutionary influences.
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p2+2pq+q2=1
Things that change allele frequency:
1. ________________________________-Allele frequencies slowly changing over time by chance
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Some alleles can be bred out of the gene pool
2. ________________________________-Movement of alleles from one population to another
3. ________________________________-New alleles arising from mutations
4. ________________________________-Mates choosing certain traits
5. ________________________________-Traits giving an advantage to organisms
Types of Selection
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Directional Selection-________________________________________________________________is favored
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Disruptive Selection-________________________________________________________________are favored
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Stabilizing Selection-_____________________________________________________________is favored over extremes
Evolution
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_________________________________________________________________________________________________
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The variations are often the result of a beneficial mutation giving the organism something it did not previously have
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Over time, ________________________________________________________________in a population
Ex. ________________________________________________________________
As conditions change, the ones with the trait survive better than those without.
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Over time, the ________________________________________________________________in the population
Misconceptions about Evolution
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Does not address how life began
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Has nothing to do with the formation of the universe
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Occurs as traits become more common in a________________
Changes are not huge
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Changes are ________________________________, and adaptations spread through populations
Individual organisms do not evolve
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________________________________________________________________cause natural selection
Organisms do not give rise to other species of organisms
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While mutations are random, evolution is guided by ________________________________
Organisms cannot choose to evolve
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Was accepted well before Darwin. Darwin came up with HOW it occurs (________________________________)
Evolution is ________________________________
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Cosmic evolution is the realm of ________________, not biology
It is ________________________________________________
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________________________________is a different field. Evolution only acts on organisms that
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Offspring will not be significantly different from parents, only ________________
Not all populations survive
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Evolution does not ensure survival; ________________ ________________ (inevitable)
Speciation
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One species ________________________________
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A species is a group of organisms that can r________________________________________________________________
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Dogs are the same species (Labradoodle-fertile)
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Donkeys and horses are not (Mule-sterile)
Usually occurs when part of the population becomes ________________________________________________
Descent with Modification
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Darwin’s way of describing evolution.
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The similar species (ex. The different species of Finch on the Galapagos Islands) all had a ________________
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Often caused by changing environmental conditions
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For the finches, it was ________________________________________________
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A mother population of finches that changed over time into all of the different species that we see now.
Finches from the initial population that had slightly larger beaks did better than those with smaller beaks
when large nuts and seeds were the primary food source available
This led Darwin to conclude that, over millions of years, _____________________________________________
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The “________________________________________________”
Patterns in Evolution
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________________________________Evolution
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Evolution towards similar features in ________________________________
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________________________________Evolution
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Evolution away from features ________________________________________________
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________________of birds, insects and mammals
Ancestor of mammals led to wide variety of features
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Evolving in ________________________________________________________________________________
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“Evolutionary Arms Race”
Adaptive Radiation
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Many species evolving from a ________________________________________________
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Ex. ________________________________________________
When Evolution Does Not Occur
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If environmental conditions change and species are unable to adapt, the result is ________________________________
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Sometimes the reason is _______________________________
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Extinction is the death of the last member of a species
Food or water sources being depleted
Other times, it is ________________________________
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Asteroid killing dinosaurs
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The current one we are causing…
Evidence for Evolution
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Evolution is one of the best supported Theories in all of science
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Evidence for evolution comes from the following:
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_________________
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Remnants of ________________________________
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Can be frozen organisms, mineralized skeletons, imprints, organisms trapped in amber, or other
remnants
Biogeography
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________________of organisms throughout the world
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Different organisms live in different climates
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Little differences, even though they are clearly related
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________________________________-study of development
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Anatomy
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________________structures-similar structures in organisms that are not closely related
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Same bones, same places, different species
________________________________Structures
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Structures in an organism that once had a function, but _______________________________
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Examples:
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Appendix(?), Goosebumps, tail bone, wisdom teeth
DNA Evidence
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All organisms, past and present, ________________
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All humans are ________________similar
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Humans and chimpanzees share ________________of DNA
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Humans and grass have ________________similar DNA
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Humans and bacteria have ________________similar DNA
Follows “________________________________” pattern
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Organisms more closely related have ________________________________________________
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The bases and cell structures are the same, coded from common DNA
Why Do We Study Evolution?
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Understanding the past is nice
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More importantly, it unifies all fields of Biology
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“Nothing in biology makes sense, ________________________________________________.” Theodosius Dobzhansky