Name: ______Period:____
History of Biological Diversity
Evolution: Darwin’s travel
Developing the Theory of Evolution
The Galápagos Islands
Darwin noticed that the different islands all seemed to have their own, ______different varieties of animals.
Somewhat similar species that suited their ______environment.
Origin of Species: ______
In 1859 On the Origin of Species presented evidence and proposed a mechanism for evolution that he called ______.
Today, scientists use ______to mean cumulative change in a group of organisms through time.
Natural selection is _____ synonymous with evolution – it is a ______by which evolution occurs.
______(instead of nature) humans select which organisms get to reproduce and pass on genes.
Peppered Moth: Natural Selection
•The light colored form was the predominant form in ______prior to the Industrial Revolution.
•Around the middle of the 19th century the darker form began to appear. It was first reported in 1848. By 1895 ______of the moths in Manchester were the dark variety.
•In recent years, the burning of cleaner fuels and Clean Air regulations has reduced the pollution there and the lighter colored moths have increased in numbers.
Types of Selection
a. ______– humans select for variations
in plants and animals that they find useful.
b. ______also means “Survival of the Fittest”.
- Fitness in this sense does ______mean strongest.
- Fitness in Darwin terms means reproduction. The one who ______long enough to reproduce the most is the one with the ______fitness.
Types of Natural Selection
Evolution acts on the phenotype of the individual, not the genotype.
There are 4 types of selection that can occur on a population.
1. Directional Selection
– when individuals at ______end of the curve have a higher fitness than individuals in the middle or at the ______end of the curve.
2. Stabilizing Selection
– when individuals near the ______of the curve have higher fitness than individuals at either end of the curve, narrowing of the graph.
3. Disruptive Selection
– when individuals at either end have a higher fitness and individual near the ______of the curve are selected against.
Over time with enough selection a population can go through genetic drift.
- ______– random change in allele frequency.
4. Sexual Selection: the ability to attract a ______
Support for Evolution
Evidence for evolution comes from:
1. The ______record: remains in layers of rock
2. Comparative ______
a. ______Structures
b. ______Structures
c. ______Structures
3. Comparative ______
4. Comparative ______
5. ______distribution
1. Support of Evolution: Fossil Record
•Fossil Record – Fossils are the remains of ancient organisms found in ______of rock in the Earth.
•The layers of rock tell the ______of the Earth, while the fossils found within the rock tell a history of life.
•The fossils are thought to be the ______as the rock they are found in.
Researchers consider ______major classes of traits when studying transitional fossils:
•______traitsare newly ______features, such as feathers, that do not appear in the fossils of common ancestors.
•______traitsare more ______features, such as teeth and tails, that do appear in ancestral forms.
•
2. Support for Evolution: Comparative Anatomy
• A. Homologous structures are anatomically similar ______inherited from a common ______.
•Similar ______with ______function
(similar bones)
(common ancestor)
•B. Analogous structures can be used for the same ______and be superficially similar in construction, but are ______inherited from a common ancestor.
•Structures are ______but have ______function.
•C. Vestigial structures are structures that are the ______forms of functional structures in other organisms.
•Evolutionary theory predicts that features of ancestors that ______longer have a function for that species will become ______over time until they are lost.
3. Support for Evolution: Comparative embryology
•Embryos of many animals with back-bones are very ______.
4. Support for Evolution: Comparative Biochemistry
______ancestry can be seen in the complex metabolic molecules that many different organisms share.
The more ______related species are to each other, the greater the biochemical similarity.
Similarities in ______and protein sequences suggest relatedness.
5. Support for Evolution Geographic distribution
The distribution of ______and animals that Darwin studied were what first suggested evolution to him.
The distribution of plants and animals around the world is studied in the field of ______.
Evolution is linked to migration patterns, climate, and geological forces (such as plate tectonics).
______- an inherited trait that increases a population’s chance of survival and reproduction in a particular environment
______is a measure of the relative contribution an individual trait makes to the next generation.
The better an organism is ______to its environment, the greater its chances of survival and reproductive success.
Through ______, populations often become suited to a specific job called a niche.
•1. niche –the role a population plays in a habitat
- job, profession, role
•2. Competition arises when 2 populations ______the same niche.
Adaptation
Types of adaptations
______is a suite of morphological adaptations that allow an organism to blend into its environment.
______is a type of morphological adaptation where a species evolves to resemble another species.
Population Genetics - study of the traits in a population
A. Population – a group of interbreeding organisms (a species) living in a ______area
B. Gene Pool – ______genetic material of all the members of a population
C. Gene Flow-the transfer of allele or genes from ______population to ______
D. Genetic Drift- any change in the allelic frequency in a population that results from ______.
E. Allele – forms that a ______can take
F. Allele Frequency – the number of each allele for a trait
This “changing of the gene pool” (allele frequency) has a name —› Evolution.
Evolution – the changes in the gene pool of a population over time.
Speciation – formation of a ______species
1. Reproductive Isolation: 2 or more species ______interbreed
2. Geographic /Allopatric Isolation: 2 populations are separated by ______barriers ●examples: rivers, mountains, bodies of water
Types of Evolution
Convergent Evolution: less alike to ______alike
Divergent Evolution=Adaptive Radiation: more alike to ______alike
Coevolution:evolve ______
Punctuated equilibrium: happens in ______period of time
Convergent Evolution:
Occurs when ______organisms that live in ______environments become more alike in appearance and ______.
Less alike to more alike
Examples: - Bird wings/insect wings
- Shark fins/dolphin fins
Divergent/Adaptive Evolution
______species gives rise to ______species
More alike to less alike
Also known as adaptive radiation.
Examples: - Darwin’s Finches.
- Brown bears and polar bears
Co-evolution
Co-evolution occurs when, ______or more organisms evolve ______.
Gradual equilibrium
Predicts that little of evolutionary change takes place in ______gradual steps
Punctuated equilibrium
predicts that a lot of evolutionary change takes place in ______periods of time tied to speciation events.
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