Transcript 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,