Theory of Evolution
description
Transcript of Theory of Evolution
![Page 1: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/1.jpg)
![Page 2: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/2.jpg)
Idea of Evolution
Charles Darwin (1809-1882) English naturalist Took a trip around the world on a ship called
H.M.S. Beagle Mostly fascinated with the Galapagos Islands Best known for his theory of evolution by
natural selection
![Page 3: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/3.jpg)
Idea of Evolution
Galapagos Islands Groups of animals vary from island to island
Ex: tortoises on each island resemble each other but differ in the shape and function of their shells
Ex: finches on each island resembled each other but differ in the shape and function of their beaks
Darwin believed these unique animals all came from a common ancestor and they changed/adapted to their environment
![Page 4: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/4.jpg)
Idea of Evolution
Evolution Development of new types of organisms over
time Heritable change in the characteristics within
a population from one generation to the next
![Page 5: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/5.jpg)
Ideas of Darwin’s Time
Scientists thought all species were permanent and unchanging
The Earth was believed to only be a few thousand (not billions) of years old
Charles Lyell was a English geologist that believed the Earth’s surface continues to change Influenced Darwin
![Page 6: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/6.jpg)
Ideas of Darwin’s Time Jean-Baptiste Lamarck
French biologist that supported the idea that populations of organisms change over time
Also believed in biogenesis of simple organisms
Proposed that individuals acquire traits during lifetime from behavior and pass them onto offspring Called Theory of Acquired Traits
![Page 7: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/7.jpg)
Darwin’s Ideas Around the same time Darwin and Wallace
formed theory to explain evolution
Published book On the Origin of Species in 1858 Book explained how evolution occurs by
means of natural selection
![Page 8: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/8.jpg)
Descent with Modification Idea that every species must have
descended by reproduction from pre-existing species that arrange over time Ex: finch beaks at Galapagos
![Page 9: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/9.jpg)
Natural Selection
Mechanism from descent with modification 1. Overproduction
More offspring are produced than survive to maturity
2. Genetic variation Traits vary within a
species Ex: deer fur
thickness is passed on to future offspring
![Page 10: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/10.jpg)
Natural Selection (cont’d) 3. Struggle to survive
Organisms need to compete with each other known as “struggle for existence”
When an organism is successful in a new environment its called an adaptation
4. Differential Reproduction Organisms best
adapted for an environment will survive best and reproduce
Survival of the fittest The ability for an
organism to reproduce and pass on adaptations
![Page 11: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/11.jpg)
The Fossil Record
Fossils Remains of an organism
that died long ago Some are remains of
extinct organisms, meaning the species is no longer alive
Superposition Idea that strata form in
layers where the layers closest to the top are the younger than below
![Page 12: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/12.jpg)
The Fossil Record Relative Age
Age compared to other fossils in order of old to young
Absolute Age Using radiometric dating to get actual number age
![Page 13: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/13.jpg)
The Fossil Record
Scientists use these relative and absolute ages to try and make the history of life on Earth as precise as possible
Fossil records are incomplete history because not all organisms have left fossils behind Fossils can easily be
destroyed during the process Finding fossils is rare also
![Page 14: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/14.jpg)
Transitional Species We can infer that species have gradually
changed based on the fossil record Scientists have hypothesized ancestors and later
descendant species
Organisms with features that are between hypothesized ancestors
![Page 15: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/15.jpg)
Biogeography Study of locations of organisms around the
world
Darwin used this method when exploring islands and observed animals variation based on environment
![Page 16: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/16.jpg)
Anatomy and Embryology
Anatomy: study of the body
Embryology: study of development
Homologous structures Anatomical structures that
originated by heredity from a structure in most common ancestor Ex: bones in arms of humans,
penguins, alligator and bat Related structure but function
may differ
![Page 17: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/17.jpg)
Anatomy and Embryology
Analogous Structures When structures have
similar function, but did not develop the same way Ex: wings of bat vs.
bird
Vestigial Structures Organs that no longer
serve a function in an organism
Ex: human tail bone, appendix
![Page 18: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/18.jpg)
Phylogeny
Relationships among groups of organisms
Can make a “tree” of animals evolved Trunk of the tree would
represent species that are closely related
Branches represent a separate population or lineage
![Page 19: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/19.jpg)
Caribbean Anole Lizard
Found in the Caribbean islands of Cuba, Hispaniola, Jamaica, and Puerto Rico Each lizard species body type differs by their habitat
Ex: stocky body and long legged lizards are best adapted for tree truck environments, slender bodies and long tails are best adapted for grassy environments
Hypothesis #1: An ancestral anole species specialized for living on twigs originally lived on one island and later migrated to other islands
OR
Hypothesis #2: Each twig-dwelling species evolved independently on each island from distant ancestor anole species
![Page 20: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/20.jpg)
Evolution in Action
Biologists tested the hypothesis by comparing DNA from the various species DNA evidence supported hypothesis 2 that
each lizard evolved independently on each island
Convergent Evolution Process by which different species
evolve similar traits Ex: sugar glider of Australia and flying
squirrel of North America came from different ancestors but evolved similar adaptations to their environment
![Page 21: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/21.jpg)
Divergence & Radiation Divergence evolution
Process by which the descendants of a single ancestor diversify into species that each fit different parts of the environment Ex: lizards with genes for large toe pads and
short legs ran slowly on the tree trunks and fell easily to predators, lizards with long legs and small toe pads were able to slip away and reproduce
![Page 22: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/22.jpg)
Divergence & Radiation
Adaptive Radiation Pattern of variation when a new population in
a new environment undergoes divergent evolution
![Page 23: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/23.jpg)
Artificial Selection Process the occurs when
human breeders choose individuals that will parent the next generation Ex: faster greyhounds, smaller
tea cup dogs, high milk yield cows, high yielding grain per stalk
Darwin hypothesized domesticated dogs diverged from wolves DNA evidence indicated
similarities with wolves in East Asia, supporting Darwin’s hypothesis and humans selected domestic dogs from wolf population 15,000 years ago
![Page 24: Theory of Evolution](https://reader036.fdocuments.in/reader036/viewer/2022081519/56813c9d550346895da648a1/html5/thumbnails/24.jpg)
Coevolution
Evolution is on-going and many species may evolve together
Coevolution When two or more species have evolved
adaptations to each other’s influence
Predator/Prey Interactions
Introduction of new species
Creating antibiotics