Charles Darwin 19th century English naturalist
developed a theory on how evolution works
studied on the Galapagos Islands because each island had different environments
wrote On the Origin of Species
Darwin’s Theory Species evolve from a common ancestor
Variation – slight difference in an inherited trait of individual members of a species occurs as a result of mutations during sexual
reproduction
Natural Selection "Survival of the Fittest” organisms with variations that help them
survive, live longer and are therefore able to reproduce to pass on those variations ex. tortoises with longer necks will survive
longer than tortoises with short necks if the food sources are up high
Adaptations an inherited trait that increases an
organism’s chance of surviving and reproducing in its environment
3 Types of Adaptations Structural – involve
physical characteristics ex. coloration, shape
Behavioral – involves the way an organism acts ex. hunting at night,
moving in herds
Functional – involve internal body systems ex. hibernation,
temperature regulation
Environmental Interactions
Camouflage
an adaptation that enables a species to blend in with its environment
Mimicry the resemblance of
one species to another species
Comparative Anatomy the study of similarities and differences
among structures of living species
Homologous Structures – body parts of organisms that are similar in structure, but different in function
Analogous Structures - body parts that perform a similar function, but differ in structure ex. bird wings and insect wings
Vestigial Structures body parts that have lost their original
function through evolution
shows that the structures served a purpose at one point, but now are no longer needed ex. cormorant wings, whale pelvic bones
Molecular Biology Scientists can use DNA to show how closely
related organisms are
Divergence – the point at which an organism breaks away from its common ancestor
The Fossil Record The Fossil Record – made up of all the fossils
ever discovered on Earth provides evidence that species have changed over
time
Fossil – the remains or evidence of once-living organisms
Fossil Formation Mineralization
minerals in water replace the organism’s original material and harden into rock
Carbonization extreme pressure drives
off the organism’s liquids and gases leaving only the carbon outline
Fossil Formation Molds and Casts
Mold – impression of an organism in hardened mud or sand
Cast – a fossil copy of an organism in a rock created by sediment filling in the mold
Fossil Formation Trace Fossils
preserved evidence of the organism’s activity, like footprints
Original Material original tissues of an
organism, like insects in amber (tree sap)
Relative-Age vs. Absolute-Age
Relative-Age – scientists determine the relative order in which rock layers were deposited( Most Accurate when the rock layers are undisturbed.) Law of Superposition – things on the top are the youngest
and things on the bottom are the oldest.
Absolute-Age (Radioactive Dating)– scientists use the ratio of unstable isotopes to stable isotopes to find the age of rocks; more precise ex. carbon-14 dating
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Extinctions Extinction – occurs when last
individual organism of a species dies Mass Extinction
when many species become extinct within a few million years or less
there have been 5 mass extinctions in the Phanerozoic eon
Causes of Extinction Sudden change – like meteor
impact or volcanic eruption Gradual change – like tectonic
plates or sea level changes
The immediate ancestors of humans were members of the genus Australopithecus . The australopithecines (or australopiths) were intermediate between apes and people. Both australopithecines and humans are biologically similar enough to be classified as members of the same biological tribe--the Hominini . All people, past and present, along with the australopithecines are hominins . We share in common not only the fact that we evolved from the same ape ancestors in Africa but that both genera are habitually bipedal , or two-footed, upright walkers. By comparison, chimpanzees, bonobos, and gorillas are primarily quadrupedal , or four-footed.
The Common Ancestor https://
www.youtube.com/watch?v=HphLBNGCBNk
Evidence of Evolution https://
www.youtube.com/watch?v=cC8k2Sb1oQ8
Which of the following correctly describes the general trend in hominid evolution?
A. larger body size, broad forehead, smaller brains
B. increase in brain capacity, bipedalism, use of tools
C. thickening of the skull, protruding teeth, organized hunting
D. large canine teeth, small skulls, diet of coarse plant material
Biogeography is the study of the location of organisms around the world. Which of the following best explains how biogeography can provide evidence for evolution?
A. It shows that organisms have structures that serve no purpose but that resemble structural roles in related organisms.
B. It shows that there are similarities and differences among the DNA of different species.
C. It shows that organisms have changed gradually over millions of years.
D. It shows that some organisms that are unrelated have developed similar adaptations to similar environments.
In his trips to the Galapagos Islands, Charles Darwin observed that 4 of the 13 species of the islands' finches have beaks adapted to eating specific foods. Which best explains how these facts provide evidence for divergent evolution?
A. The finches were different species but resemble each other because of how they evolved in a similar environment.
B. The finches descended from similar ancestors and have evolved adaptations in response to each other's influences.
C. The finches descended from the same ancestor but evolved along their own lines in isolation from each other.
D. The finches descended from a common ancestor but evolved differently in response to their environment.
The Evolution Of Humans https://
www.youtube.com/watch?v=MsHEAnPX59Y
Classification- putting things into groups based on shared characteristics
There have been many different ideas about how to classify living things.
Aristotle placed all organisms into 2 large groups- plants and animals
Linnaeus’ System Linnaeus founded modern
taxonomy.
Taxonomy- the science of describing , classifying , and naming living things
Based on 7 hierarchical categories
Simplified the naming of living things by giving each species a two-part specific name “Binomial nomenclature”
Binomial Nomenclature
Felis domesticus
Genus Species
In a scientific name, the first part of the name is the organism’s genus. Similar species are grouped into one genus. Ex: Felis
The second part of the name identifies the species- a group of organisms that have similar traits and are able to produce fertile offspring.
Classification TodayTaxonomists use an eight-
level system to classify living things based on shared characteristics.
The more characteristics the organisms share, the more closely related the organisms may be.
DOMAIN 1: ARCHAEA ARCHAEBACTERIA
Unicellular prokaryotes
Often live in harsh environments
some produce food by chemosynthesis (energy obtained from places other than the sun)
DOMAIN 3: EUKARYA EUKARYOTES
Complex cells; nuclei and organelles in cells
Some are unicellular Some are multicellular
The domain Eukarya is divided into 4 Kingdoms:1. Protista2. Fungi3. Plantae4. Animalia
Domain Eukarya: Kingdom Protista
One celled or Multicellular organisms that can either be plant-like, animal like, or both
Algae, Amoebas, Paramecium , Euglena
Domain Eukarya: Kingdom Fungi Multicellular Cell wall Does not perform
photosynthesis Absorbs nutrients Reproduce using spores.
Domain Eukarya: Kingdom Plantae Cell wall Perform photosynthesis Vascular vs. nonvascular Flowering vs.
nonflowering
Domain Eukarya: Kingdom Animalia Multi-cellular organisms that lack
cell walls
Range from simple to complex
Invertebrates- Do not have a backbone Worms Sponges Jelly Fish Mollusks Insects
Vertebrates – Have a backbone Fish Amphibians Reptiles Birds Mammals
Dichotomous KeyA series of descriptions arranged
in pairs that can be used to identify an unknown organism
The chosen descriptions leads to another pair of descriptions or to the identification of the organism
Cladogram A branched diagram that shows the relationships
among organisms
New characteristics appear before each branch