THEORY OF EVOLUTION

Chapter 16

Idea of Evolution

◦Charles Darwin (1809-1882)◦English ________________◦Took a trip around the world on a ship called

________________ Mostly fascinated with the ________________ Islands

◦Best known for his theory of ________________ by natural selection

Darwin’s Journey◦ Began in ________________◦ Sailed on a ship called the H.M.S. Beagle◦ Five year voyage sailing around the coast of ________________

________________ and ________________

Observations Aboard the Beagle◦Darwin collected 68 species of ________________◦Wrote about the different characteristics of habitats and species that live there

◦Species vary ________________◦There are similar organisms around that world with

similar ecological ________________◦Ex: Rhea birds in S. America and ________________ in Africa

Observation Aboard the Beagle◦Species vary ________________

◦Related animals species often occupy different habitats within a ________________ area

◦Ex: Tortoise ________________ ________________ among Galapagos Islands

Observation Aboard the Beagle◦Species vary ________________ ________________

◦Some fossils of ________________ animals were similar to living species

◦Ex: Armadillo ________________ compared to modern day armadillos

Darwin’s Findings◦Galapagos Islands

◦Groups of animals ________________ from island to island◦ Ex: tortoises on each island resemble each other but differ in

the shape and function of their ________________◦ Ex: finches on each island resembled each other but differ in

the shape and function of their ________________◦Darwin believed these unique animals all came from a

________________ ________________ and they changed/adapted to their environment

Idea of Evolution◦Evolution

◦Development of new types of organisms ________________ ________________

◦Heritable ________________ in the characteristics within a population from one generation to the next

Ideas of Darwin’s Time◦Scientists thought all species were ________________ and unchanging

◦The Earth was believed to only be a few ________________ (not billions) of years old

◦During Darwin’s time, new research was being done to figure out the ________________ of the Earth

Ideas that Influenced Darwin

◦James Hutton was a geologist in 1700’s◦Made connections between mountains, valleys, and layers of ________________

◦Believed the ________________ was older than thousands of years -- a time so old for the human mind to image

◦The Earth changes very ________________ and some layers can accumulate as the environment is changing

Ideas that Influenced Darwin◦Charles Lyell was a English ________________ that believed the Earth’s surface continues to change◦He explained that past processes that occurred are still occurring now ◦Ex: ________________ erupted in the past and

still today◦Published a great work called ________________

______ ________________ in 1830 that built on the work of Hutton◦Darwin read this book while on his journey

around the world

Ideas that Influenced Darwin◦Jean-Baptiste Lamarck

◦French naturalist that ________________ the idea that populations of organisms change over time

Ideas that Influenced Darwin

◦Proposed two hypotheses: Called Theory of ________________ ________________ ◦ Organisms could ________________ during their lifetime by

using or not using selected parts of the body◦ Individuals could pass these ________________ traits on to

their offspring◦Ex: Giraffes could ________________ their neck by

stretching over a period of time to get the height they needed to eat and survive and then pass the longer neck trait to their ________________

Ideas that Influenced Darwin

◦Thomas Malthus was an English economist in the 1790s◦ Reasoned that if the human population grew continuously,

there would not be enough ________________ for everyone◦ His reasoning explained why plants and animals produced

more a high amount of ________________ since a portion will not ________________ due to environmental factors◦ Ex: Maple tree produces ________________ of seeds each

summer◦ Ex: Oysters produce ________________ of eggs each year

with the understanding that only a fraction will survive

Darwin’s Ideas◦ Around the same time Darwin and Wallace formed

________________ to explain evolution◦ Darwin was able to publish his book first called _______

_______ _____________ ______ ____________ in 1858◦ Book explained how evolution occurs by means of

________________ ________________

Artificial Selection◦Darwin studied ________________ breeders◦Farmers would select to breed only _____________ with

the largest fruit, or the _____________ that produce the most milk◦ Darwin called this process ________________ ________________

◦Nature provides the ________________, and humans select hose they find to be useful and allow them to breed and pass on ________________ to offspring

Evolution by Natural Selection

◦Mechanism from descent with _____________

◦1. Struggle for Existence◦ Organisms produce more

offspring than can _____________

◦ Ex: grasshoppers lay over 200 _____________ at a time, but only a fraction survive

◦2. Variation and Adaptation◦ Traits vary within a

species and their environment called _____________

◦ These adaptations help increase _____________ to survive◦ Ex: _____________ with

coral snake and scarlet snake

Natural Selection (cont’d)◦ 3. Survival of the Fittest

◦ Organisms best _____________ for an environment will survive best and _____________

◦ The ability for an organism to _____________ and pass on adaptations

◦4. Natural Selection◦ Process by which

organisms with _____________ most suited to their local environment survive and leave more _____________

◦ Organisms _____________ their mate based on desired traits

Common Descent◦Idea that every species must have ___________ by reproduction from pre-existing ___________ that arrange over time◦Ex: finch ___________ at Galapagos

◦All species – living and extinct – are descended from ancient _____________ ancestors

Transitional Species◦Organisms with features that are _____________ hypothesized ancestors

Age of the Earth & Fossils◦Noted that fossils of extinct animals _____________ living species

◦Relative Age◦Age _____________ to other

fossils in order of old to young

◦Absolute Age◦Using radioactive dating to

get _____________ _____________ age

Age of the Earth and Fossils

◦Age of the Earth◦Geologists are certain based on

evidence via radioactive dating to indicate the Earth is about _______ _____________ years old

◦Fossils◦_____________ of an organism that died

long ago◦Many fossils form a series that can

trace back to an ancient extinct _____________

◦Superposition◦Idea that _____________ form in layers

where the layers closest to the _______ are the younger than below

Biogeography◦Study of where organisms live _____________ and where

they and their ancestors lived in the _____________ ◦Darwin used this method when exploring islands and

observed _____________ vary based on their _____________

◦Closely related but Different◦ Darwin believed that the finches of the _____________ all came

from a common ancestor in the _____________ ◦ Over time, _____________ selection produced a variation of

species of finches◦Distantly Related but Similar

◦ Darwin noted that organisms that are _____________ related and inhabit similar environments have _____________ qualities

Anatomy and Embryology◦Anatomy: study of the __________

◦Embryology: study of _____________

◦Homologous structures ◦Anatomical structures that

originated from the _____________ common _____________ ◦Ex: bones in arms of humans,

penguins, alligator and bat◦Related _____________ but

_____________ may differ

Anatomy and Embryology

◦ Analogous Structures◦ When structures have

similar _____________ , but did not develop the same way◦ Ex: wings of bat vs. bird

◦ Vestigial Structures◦ Organs that no longer

serve a _____________ in an organism

◦ Ex: human tail bone, appendix

Anatomy and Embryology

◦Embryology◦ Similar patterns of

embryological _____________ provide further evidence that organisms have descended from a _____________ ancestor

◦ Many animals look _____________ during development and produce _____________ tissue

Genetics and Molecular Biology◦At the molecular level, the _____________ _____________ and homologous molecules provide _____________ of common descent

Phylogeny

◦_____________ among groups of organisms

◦Can make a “__________” of animals evolved◦Trunk of the tree would

represent species that are _____________ related

◦Branches represent a _____________ population or lineage

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

Evolution in Action◦Biologists tested the hypothesis by comparing _____________ from the various species ◦DNA evidence supported hypothesis 2 that each

lizard evolved _____________ on each island◦Convergent Evolution

◦Process by which _____________ species evolve _____________ traits ◦ Ex: twig-dwelling species came from

different ancestors but evolved similar adaptations to their environment

Divergence & Radiation◦Divergence evolution

◦Process by which the descendants of a _____________ ancestor diversify into species that each fit _____________ parts of the environment◦Ex: All breeds of dog share a common ancestor

with wolves

Divergence & Radiation◦Adaptive Radiation

◦Pattern of diversity when a new population in a new _____________ undergoes divergent evolution

Coevolution◦Evolution is on-going and many species may evolve _____________

◦Coevolution ◦When _____________ or more species have evolved

adaptations to each other’s _____________ ◦Ex:

◦Predator/Prey Interactions ◦Introduction of new species◦Creating antibiotics