Download Evolution

Evolution
From the
Beginning
Mammals
Dinosaurs
Mammals began to
evolve during this
time
First Land plants
and a variety of
marine life
Takes up about 88%
of Earths history
Precambrian Time
 Is the longest time period
 Prokaryotes were first
 Anaerobic forms of life Ex. bacteria , these
are things that don’t use oxygen
 Later photosynthetic forms of life
appeared. Which added oxygen to the
atmosphere.
 Aerobic, oxygen using, forms of life evolved
and eukaryotes appeared
Paleozoic Era
 Early in the Paleozoic Era there was a
diversity of marine life
 Many invertebrate animals, with hard
shells, also things such as jellyfish, worms,
and sponges. Things with out a
exoskeleton.
 Ancestors of squids and octopuses
appeared along with aquatic arthropod
 First vertebrates appeared. First land plants
appeared
 During this time period vertebrates began
to invade the land.
 Reptiles, amphibians, winged insects,
appeared
 At the end of this era there was a mass
extinction affecting both plants and
animals on land and in the sea
 Killing off as much as 95% of the
complex life in the ocean
 Did not affect many fish and many
reptiles also survived
Mesozoic Era
 Events that occurred include the
increasing dominance of dinosaurs.
 Flowering plants appeared
 Birds and flying reptiles
 Mammals evolved
 Leafy tree shrubs
 At the end there was a mass extinction
killing off half of all the plant and animal
groups and all of the dinosaurs
Cenozoic Era
 Because of the extinction of the dinosaurs it
gave way for mammals in the Cenozoic Era to
take over.
 They took over on the land, water, and the air.
 Whales and dolphins evolved; so did grazing
animals
 So did grasses and flowering plants
 During this period there were a series of ice
ages.
 This is the time period humans evolved
Fossil Record
 Relative Dating – dating a fossil by its
relative placement in the rock bed
 Radioactive/Carbon Dating – uses the
half life of radioactive isotopes to find out
how old the fossil is
 How is a fossil formed- sediment settles
on the dead organism and with time and
pressure the remains become fossilized (
rocks)
Pattern of Evolution
 Adaptive radiation - things evolve from a common
ancestor
 Convergent evolution - having similar
characteristics but are not from the same ancestor
Ex. Sharks, dolphins
 Coevolution - When two species evolve in
response to changes in each other over time Ex.
Flowers and pollinators
 Punctuated equilibrium -long stable periods
interrupted by brief periods of rapid change
 Gradualism -the gradual change from on species
to another with intermediate species
Adaptive radiation
Convergent evolution
Coevolution
Darwin
 Voyage of the Beagle 1831- Darwin went to
the Galapagos Islands .
 Darwin observed that the characteristics of many
animals and plants varied noticeably among the
different islands
 Evolution is the change in a species over
time, the process by which modern
organisms have descended from ancient
organisms.
 Artificial selection- nature provides the
variation and humans select those
variations that they have found useful
 Struggle for existence- members of each
species compete regularly to obtain food,
living space, and other necessities of life
 Fitness-ability of an individual to survive
and reproduce in its specific environment
 Adaptation- inherited characteristic that
increase an organism’s chance of
survival
 Natural Selection (survival of the fittest)these things are selected for or chosen
for. Things survive based on how fit they
are .
 Cannot be seen directly, only observed as
changes in a population over time
 Over time, natural selection results in
changes in the inherited characteristics of
a population. These changes increase a
species’ fitness in its environment.
 Descent with modification- over time,
natural selection produces organisms
that have different structures, niches, or
occupy different habit
 Jean- Baptiste Lamarck- Inheritance of
acquired traits. Means that what traits
your parents acquired while alive they
can pass on to you.
Structures
 Vestigial- features or structures that have no
use but seem to be left over from some
evolutionary change.
 Ex. Wisdom teeth, Whales pelvis
 Homologues- They are common characteristics
between like species.
 Ex. Bone structure of a human arm and frog arm
Selection
 Directional- moves the population to one
side or the other
 Stabilizing- moves it back to the middle
 Disruptive- moves it to the extremes
Genetic Drift
 Genetic Drift
 Founders Effect- the original founders
are the base of the gene pool
 Bottleneck- after the population has been
dramatically killed off it lowers the gene
pool
Hardy-Weinberg Principle
 Genetic equilibrium- allele frequencies
remain constant
 5 conditions for Hardy-Weinberg
 Random Mating
 Large Population
 No movement into or out of the population
(immigration, emigration)
 No mutation
 No natural selection
Speciation
 Speciation- the formation of a new
species
 What is a species?
 It is a group of organisms that breed with
one another and produce fertile offspring
 This means that individuals in a species
share the same gene pool
 Gene pool- is all the genes, including all the
different alleles, that are present in the
population
What causes Speciation?
 Selection- mainly disruptive
 Isolation Mechanisms
 Reproductive isolation-When the members of two
populations cannot interbreed and produce fertile
offspring
 Behavioral isolation- this occurs when two
populations are capable of interbreeding but have
different courtship rituals
 Geographic isolation- live in different places,
separated by geographical barriers
 Temporal isolation- reproduce at different times
Classification
 What is classification?
 The naming or the putting things into groups
based off of specific criteria
 Why do we classify things?
 Helps us to distinguish between things.
 The original classification was a
description of the organism.
Classification
 Naming order-Domain, Kingdom, Phylum, Class,
Order, Family, Genus, Species
 3 Domains- Archaea, Bacteria, Eukarya
 5 Kingdoms- Monera, Protista, Fungi, Plant, Animal
 Phylum- there are 36 of these
 Ex. Chordata, Annelide, Arthopoda,
 Taxonomy- is the practice and science of
classification
 Binomial Nomenclature-Carolus Linnaeus came up
with this in the mid 1700s. It is a two name system
to classify, group, things into. This is the one still
used today.
Human Scientific name








Domain- Eukarya- multicellular,
Kingdom- Animala- no cell wall
Phylum- Chordata- has a back bone
Class- Mammalia- has hair, mammary glands
Order- PrimataFamily-HominidaeGenus- Homo
Species- Sapiens
Evolutionary Classification
 Phylogeny- the study of evolutionary
relationships among organisms
 Evolutionary classification- it’s the
strategy of grouping organisms together
based on their evolutionary history
 Cladogram- a diagram that shows the
evolutionary relationships among a group
of organisms.
Phylogeny
Cladogram
Domain Archaea







Unicellular
Prokaryotic
Cell Wall
Both Autotrophic and Heterotrophic
Most cannot live in oxygen
Live in the extreme areas of the world
Kingdom Archaebacteria
Domain Bacteria






Unicellular
Prokaryotic
Thick Rigid Cell Wall
Both Autotrophic and Heterotrophic
Both Photosynthetic and Aerobic
Kingdom Eubacteria the larger of the 2
domains
Domain Eukarya
 Eukaryote Cell- Have a nucleus
 Kingdoms
 Protista- Greatest variety, most are
unicellular but some are multicellular, are
both heterotrophic and autotrophic
(everything that doesn’t fit into the other 3
kingdoms goes here)(Ex. Red, Brown &
Green Algae)
 Fungi- Heterotrophic, feed on dead and
decomposing organisms, they secrete
digestive enzymes into their food source,
(Ex. Mushrooms, multicellular; yeast,
unicellular)
 Plantae- multicellular, photosynthetic
autotrophs, nonmotile, cell wall,
 Animalia- multicellular, heterotrophic, no
cell wall, movable,