Download Changes Over Time and Classification

Question: Where did Darwin travel to where he observed many unusual organisms?
DARWIN’S THEORY OF EVOLUTION
Evolution — the process of change over time
In Darwin’s travels aboard the HMS Beagle, which began in 1831, Charles Darwin made
three important observations:
The world includes a tremendous diversity of living things throughout a wide
range of habitats
Animal species, like those in the Galapagos Islands, that are related, can have
different characteristics or occupy different habitats in the same area.
Fossils — preserved remains of ancient organisms, resembled
Darwin’s observations led him to develop the scientific theory of evolution which
explains how modern organisms evolved over long periods of time by natural selection.
Adaptation — a trait that helps an organism survive and reproduce.
Natural selection — process by which individuals that are better adapted to their
environment are more likely to survive and reproduce than other members of the same
species.
Factors that affect process of natural selection:
 Overproduction — species produce more offspring than one can survive (insects, fish)
 Variations — difference between individuals
 Competition — resources are limited, species must compete to survive
Question: How
Whatare
is genetic
fossils formed?
drift?
EVOLUTION
THE FOSSIL
OF POPULATIONS
RECORD
Paleontologists
— scientist
who studies
fossils
or the
preserved
remains
traces of
Genetically speaking,
evolution
is a change
in the
frequency
of alleles
in or
a population
organisms
that
have
lived
in
the
past.
over time.
Three sources of genetic variations:
Fossil record — collections of fossils organized to provide evidence about history of life
Mutations —on
charge
in including
genetic material
of cell have changed over time.
Earth,
how organisms
Genetic Recombination — during sexual reproduction each chromosome in a pair
moves independently during meiosis — in humans this can produce over
8,000,000,000 gene combinations
geneoftransfer
— passing
ofcan
genes
from
TheLateral
formation
fossils are
rare but
occur
by:one organism to another (not including
offspring)
Petrified Fossils
Molds and Casts
Preserved Remains
— remains are buried in
— hollow space in sediment quickly buried organisms are
Gene
pool
—
consists
of
all
genes,
the differentpreserved
alleles, that
a
sediment then change to
in including
the shape all
of an
by are
ice,present
volcanicinash
population
rock over time
– now
organism is called a mold; or clay before they begin to
called petrified fossil
when a mold becomes
decay.
filled with hardened
minerals it becomes a
Hardy — Weinberg principle — states that allele frequencies will remain constant or
cast.
have genetic equilibrium, unless factors cause those
frequencies to change.
The Hardy—Weinberg principle holds under these five conditions:
Relative Dating
Vs.
Radioactive Dating
1. random mating
Age of fossils is determined by comparing
Involves measuring the amounts of
2.
very
large
population
its placement with that of fossils in other
radioactive isotopes in a sample to
3. no
in or out of population
layers
of movement
rock.
determine its actual age
4. no mutations
5. no natural selection
Paleontologists use the geological time scale, or a “Calendar” of Earth’s history, to
represent evolutionary time.
Reproductive isolation, or when two populations no longer inter breed, can cause
evolution
of two separate
species.
This can time
be caused
bydivided
behavioral
geographic
After Precambrian
Time,
the geological
scale is
intoisolation,
eras (Paleozoic,
isolation
and
temporal
isolation.
Mesozoic and Cenozoic) and those eras are subdivided into periods, which range in
length from tens of millions of years to less than two million years.
Question: What is taxonomy?
CLASSIFICATION
In the 1730’s, Carolus Linnaeus, a Swedish botanist, developed a two-word naming
system called binomial nomenclature — first part of name is genus with second part of
name referring to species.
Linnaeus also developed a classification system which included seven hierarchal taxa:
Ex.
Grizzly
Bear
KINGDOM
PHYLUM
CLASS
ORDER
Animalia
Chordata
Mammalia
Carnivora
FAMILY
GENUS
SPECIES
Ursidae
Ursus
Ursus Arctos
Sometimes classification keys are used to identify organism by traits that are visible,
however scientists today now look at how closely members of groups are related.
Phylogeny — study of how living and extinct organisms are related to one another
Clade — group of species that includes a single common ancestor and all descendants of
that ancestor.
Cladogram — diagram that links groups of organisms by showing how evolutionary
lines, or lineages branched off from common ancestors.
Derived Character — trait that arose in the most recent common ancestor of a particular
lineage and passed to its decendants.
Question: What broad characteristics do biologists use to group living things into kingdoms?
DOMAINS AND KINGDOMS
Organisms are placed into domains and kingdoms based on their cell type, their ability
to make food, and the number of cells that make up their bodies.
CLASSIFICATION OF LIVING THINGS
DOMAIN
KINGDOM
CELL TYPE
CELL
STRUCTURES
# OF CELLS
MODE OF
NUTRITION
EXAMPLES
Bacteria
Eubacteria
Prokaryote
Archaea
Archaebacteria
Prokaryote
Protista
Fungi
Eukarya
Plantae
Eukaryote Eukaryote Eukaryote
( lacks a nucleus )
( lacks a nucleus )
Some cell
Cell walls Cell walls
walls
of
of
of cellulose
Cell walls
Cell walls
cellulose
chitin
with
without
PeptidePeptideSome
Chloroglycan
glycan
chloroplasts
plasts
Most
Most
Most
unicelmulticelmulticellular
lular
lular
Unicellular
Unicellular
Some
Some uni
Some green
colonial
Algae uni
Some
multi
AutoHeteroAutotroph
Autotroph or Autotroph or troph or
troph
Heterotroph Heterotroph Heterotroph
Amoeba,
Mushroom Mosses,
Slime
Yeasts
ferns,
E. Coli
Halophiles
molds
flowering
plants
Animalia
Eukaryote
No cell
walls or
chloroplasts
Multicellular
Heterotroph
Sponges,
norms,
insects,
fish,
mammals