Transcript Diversity of Life

Diversity of Life
How can this diversity be explained?
Charles Darwin and the
Beagle
-left
England in 1831
-took 5 years to complete
-was a volunteer naturalist position
-he was 22 years old
-collected plants and animals at every stop
-spent much time on the Galapagos Islands
making observations
-noticed many variations of plants and animals
from island to island
HMS Beagle
Natural Genetic Variation- differences among individuals of a species
-found in all organisms
Ex: fruit size, bacterial resistance, cows milk (volume)
Genetic Variations
Gene Pool-combined genetic information of all
the members of a population.
-typically contain 2 or more alleles
for an inheritable trait
EX: Blood Types, Coat color
4 Sources of Genetic Variation
1 Mutation- change in the sequence of DNA
-some may effect an individuals fitness (for better or worse)
2 Gene Shuffling -23 pair of chromosomes can produce 8.4
million combinations of genes
-Crossing over- produces recombinants (new combinations) with
different phenotypes (Meiosis I)
-Sexual Reproduction- produces many phenotypes but doesn’t
change frequencies (deck of cards)
3 Single Gene Traits- a single gene with 2 alleles will
give you 2 phenotypes (widow’s peak)
4 Polygenic Traits-traits controlled by 2 or more genes
-may have multiple alleles (human skin color, height)
-produces many genotypes ( gene combos.) and phenotypes (looks)
Evolution = Descent with Modification
Evolution only occurs when there is a change in gene frequency within a
population over time. Evolution is a long term change.
Compare these two examples of change in beetle populations. Which
one is an example of evolution?
1. Beetles on a diet
Imagine a year or two of drought in which there
are few plants that these beetles can eat.
All the beetles have the same chances of survival and reproduction,
but because of food restrictions, the beetles in the population are a
little smaller than the preceding generation of beetles.
2. Beetles of a different color
Most of the beetles in the
population (say 90%) have the
genes for bright green coloration
and a few of them (10%) have a
gene that makes them more brown.
Some number of generations later,
things have changed: brown beetles
are more common than they used to
be and make up 70% of the
population
Natural Selection-is one of the basic mechanisms of evolution, along
with mutation, migration, and genetic drift.
Darwin's grand idea of evolution by natural selection is relatively
simple but often misunderstood. To find out how it works, imagine a
population of beetles:
Evolution by Natural Selection
-many different actions are at work in order to make natural
selection concept successful including:
1 There is variation in traits.
For example, some beetles are green and some are
brown.
OUCH!
2 There is differential
reproduction- Since the environment
can't support unlimited population growth, not
all individuals get to reproduce to their full
potential. In this example, green beetles tend to
get eaten by birds and survive to reproduce less
often than brown beetles do.
3 There is Heredity.
The surviving brown beetles have brown baby beetles
because this trait has a genetic basis.
4 End result: The more advantageous trait, brown coloration, which
allows the beetle to have more offspring, becomes more common in
the population. If this process continues, eventually, all individuals in
the population will be brown.
What
happened to
all the green
guys?
Extinction: in some cases all variations may be selected
against and the entire population my disappear
If you have variation, differential reproduction, heredity,
and extinction, you will have evolution by natural
selection as an outcome.
Survival of the fit enough (fittest) high fitness individuals live to
reproduce, low fitness individuals perish.
Artificial Selection-choosing the traits that we want to show up in
the offspring
-nature provided the variations, humans chose the ones that were useful
-Known as Selective Breeding
There can be a down side to artificial selection. Because this
process essentially removes variation in a population, selectively
bred organisms can be especially susceptible to diseases or changes
in the environment that would not be a problem for a natural
population. Inbreeding — the mating of closely related individuals
— is also a problem. In dogs, this has resulted in breeds that have
health issues ranging from decreased life span to hip dysplasia.
Teosinte a relative of corn
Struggle for existence- members of each species compete regularly
for food, living space
An organism competes most closely with other
members of its own species, because they have
the most similar ecological needs to its own;
other species, in decreasing order of ecological
similarity, also compete and exert a negative
influence on the organism's chance of survival.
Interspecific Competition-members of different species
competing for limiting factors
Intraspecific Competition -members of the same species
competing
Evidence to support Evolution
More Modern Evidence Which Supports The Theory of Evolution
Embryonic Development and relative ages of evolution
T
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2
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4
5
6
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8
Match these organisms with the numbered embryo
Human, fish, salamander, turtle, chicken, pig, rabbit, calf
More Modern Evidence Which Supports The Theory of Evolution
Embryonic Development and relative ages of evolution
1
Fish
2
3
Salamander Tortoise
4
Chick
5
Pig
6
Calf
7
Rabbit
8
Human
Looking at embryonic
development can give
you a relative age as
well as
help you determine
how closely
related different
organisms are.
This is OLD School due
to the
advances in DNA
analysis
Which organism
Would be our closest
Ancestor ________?
The Pig, the turtle,
or the salamander
Even more Evidence for The THEORY of EVOLUTION
Homologous Structures are of the same basic structure
but used differently in the adult
Humorus
Ulna
radius
wrist
Phalangies
The STRONGEST & MOST MODERN EVIDENCE which
SUPPORTS the THEORY of EVOLUTION
DNA
Cytochrome C- protein in the electron transport chain of the mitochondria
How do we get new species? SPECIATION
What Is a Species?
A species is a potentially interbreeding population that does not
interbreed with other such populations when there is opportunity
to do so.
1.Hybridization/Artificial Selection: When 2 different species
interbreed so frequently that the resulting hybrid species will begin to
intrabreed enough to sustain itself.
2.Adaptive radiation:
The formation of a number of
diverse species from a single
ancestral one is called an adaptive
radiation. Example: Darwin’s
Finches.
3.Geographic Isolation:
The Kaibab squirrel (Sciurus aberti
kaibabensis, left) became geographically
isolated from the common ancestor with its
closest relative, the Abert squirrel (Sciurus
aberti aberti, right) in the North Rim of the
Grand Canyon about 10,000 years ago. Since
then, several distinguishing features, such as
the black belly and forelimbs have gradually
evolved.
A geographic barrier (mountain
range, river, ocean, etc.)
results in reproductive isolation
and eventual changes
occur in the newly separated
species. Example: Grand
Canyon Squirrels.
Lonesome George the last Pinta Island Giant tortoise
Can you predict the different
Vegetation heights on which these
tortoises fed??
What keeps Similar Species from Interbreeding to
possibly result in new species?
x
=
?
REPRODUCTIVE ISOLATION
Polargrizz- New Species or Hybrid
Liger
“Hercules”
the Liger (12
ft., 900 lbs.).
Male lion &
tigress
Cama
Due to size difference
of the parents they
are born through
artificial
insemination, and
most noticeably they
have no hump. Their
flat backs and
durability make them
great pack animals.
Wolphin
A rare crossbreed
of a bottlenose
dolphin and a
false killer whale
this is probably
the best example
of an animal that
is half and half.
Killer whales have
88 teeth,
bottlenose
dolphins have 44
teeth and
kekaimalu the
wolphin has 66
teeth.
1. STERILIZATION: The Mule is a cross between a donkey stallion (called a jack) and a horse
mare. Hinnies are just the opposite - a stallion horse crossed to a donkey jennet. For all
purposes, hinnies and mules are classified and shown together under the general term Mule. A
mule or hinny may be a male (horse mule or horse hinny) or a female (mare mule or mare
hinny). Sometimes horse mules (the males) are called Johns, and the mares are called
Mollies. Both male and female mules have all the correct "parts" but they are sterile and cannot
reproduce.
2. MECHANICAL ISOLATION: Two different species may try to reproduce but are unable to do so
due to physical differences. Physical differences
prevent hybridization, organs are incompatible
A friendly dog & man
3. Geographic Isolation- two populations are separated
by geographic barriers (rivers, mountains, oceans)
4. Temporal Isolation- two or more species reproduce at
different times
- some rain forest orchids open release pollen on a single
day different from the others
5. Behavioral Isolation- two populations can breed but
have different courtship rituals or other behaviors
Western Meadowlark
Eastern Meadowlark
Different Mating songs
Patterns of Evolutions in Populations do Exist
These Patterns of Natural Selection are best represented by graphs
There are 3 basic patterns of population evolution:
STABILIZING SELECTION: When the individuals in the center of the bellshaped curve have the selective advantage. The population is stable.
DIRECTIONAL SELECTION: When individuals at one end on the bell-shaped
curve have the selective advantage. Change is ocuring in the population.
DISRUPTIVE SELECTION: When individuals at the upper and lower end of
the bell-shaped curve have the selective advantage. What used to be
an advantage is no longer the case
Toxic newts video clip
how does a new species form?
1 Founding
of a new population
2 Geographic Isolation
3 Changes in the gene pool
4 Reproductive Isolation
5 Geographic Overlap
Guppy Selection Expt
http://www.pbs.org/wgbh/evolution/educators/lessons/lesson4/act2.html
The moral of the story is that if
you can not adapt to changes
in your Environment then you
will be outcompeted & die or
(worse?) not reproduce.
You have encountered this animal while backpacking in the Idaho wilderness.
What is it?
Is it the same animal as these?
How do you know?
What is its name?
Common Names
Mountain lion, Puma, Cougar, Painter, Catamount, Panther
Puma concolor
Taxonomy- the science of naming organisms and placing them into groups
To avoid confusion scientific names are used whenever possible when describing
organisms
Good Try!
- the first efforts of grouping organisms was a very lengthy descriptive
process
"Oak with deeply divided leaves that have no hairs on their undersides and
no teeth around their edges"
Introducing: Carolus Linnaeus
-Father of Taxonomy
-Highly acclaimed Botanist and
Ecologist
- Swedish
-Invented Binomial Nomenclature
1707-1778
100 Kroner (Sweden) He’s a big deal there!
Carl von Linne coat of arms
Binomial Nomenclature
Homo sapiens
Binomial Nomenclature- each species is assigned a two part name
- always written in italics
- first word is always CAPATILIZED (Genus)
- second word is always lower case (species)
Pseudotsuga menziesii
Douglas Fir
Artemesia tridentata
(Genus) (species)
Pinus ponderosa
Basin Sagebrush
Ponderosa Pine
Linnaeus developed 7 classification
levels (taxa)
Each level
is included
in the level
above it.
Most General
Most Specific
Bear Family (Ursidae)
The bear family includes eight species: the
polar bear, American black bear, spectacled
bear, giant panda, sloth bear, sun bear, brown
bear, and Asiatic black bear.
Ursus americanus
Ursus arctos
Ailuropoda melanoleuca
*has it's own genus and species
*it is highly specialized
Ursus maritimus
A schematic cladogram of the major evolutionary relationships of the Carnivora modified from
Flynn et al.
Nash W G et al. J Hered 2008;99:241-253
© The American Genetic Association. 2008. All rights reserved. For permissions, please email:
[email protected].
Modern Classification Systems
• Have added a new taxa
called a DOMAIN
• More genetically based
than physical characters
• Try to show common
descent along with
physical descriptions
• Has 8 or more taxa
where Linnaeus had just
7 taxa
Domains of Life
SIX KINGDOMS of LIFE
How are you classified?
How do you remember the order?
Dumb King Phillip Cried Oh For
Goodness Sake or
Dumb Kings Play
Chess On Fridays Generally Speaking
Domain- Eukarya
Kingdom- Animalia
Phylum- Chordata- have notochords
Subphylum- Vertebrata- vertebral
column
Superclass- Tetrapoda- terrestrial, 4limbs, bony skeletons
Class- Mammalia- hair, milk glands,
endothermic
Subclass- Eutheria- offspring develop
within mother, nourished by placenta
Order- Primata- fingers, flat nails
Family- Hominidae- upright posture, flat
face, stereoscopic vision, large brain,
hands and feet
Genus- Homo- double curved spine,
long life, long youth
Species- sapiens -well-developed chin,
high forehead, thin skull bones
Which 2 species would be more closely Canis lupus
Ursus arctos
related?
Canis domesticus
SIX KINGDOMS of LIFE
Kingdom
When Evolved
Structure
Photosynthesis
1. Bacteria
3 to 4 billion years ago
Unicellular
Sometimes
2. Archaea
3 to 4 billion years ago
Unicellular
No
3. Protista
1.5 billion years ago
Unicellular
Sometimes
4. Fungi
1 billion years ago
Unicellular or Multicellular
No
5. Animalia
700 million years ago
Multicellular
No
6. Plantae
500 million years ago
Multicellular
Yes
Prokaryotes:- No Nucleus
Eukaryotes:- True Nucleus
Plants
Animals
Kingdom Archeabacteria
Kingdom Eubacteria
Kingdom Protista
Kingdom Fungi
Phylogenetic Tree of Life
Bacteria
Archaea
Eukarya
Archae
Eubacteria
Protista
Fungi
bacteria
Prokaryote ProEukaryote
Euk-
Plantae
Euk-
Animalia
Euk-
without
Unicellular Uni-
Autotroph Autoheterotroph Hetero-
Multicell
ular
AutoHetero-
Hetero-
Auto-
MultiHetero-
Eukaryote vs. Prokaryote
Eukaryotic organisms have a TRUE
Nucleus
Prokaryotic organisms have DNA or RNA
But it is NOT contained in a nucleus
Variations to the Classification System
Botanists use a division instead of phylum
The species level can be further divided:
-Animals can be divided into subspecies(ssp.)- morphologically
different and often geographically separated (see following slide)
-Fruits (plants) are divided into different varieties(var.)morphologically different but not geographically separated, some produced by
humans (see following slide)
-Bacteria are divided into different strains(str.)- biochemically
dissimilar group within a species Example: E coli
Royal Gala
Honeygold
Jonagold
Golden delicious
Braeburn
Fugi
Malus domestica
Pink Lady
Map of Wolf subspecies of North America
Canis lupus tundrarum
(Tundra wolf)
Canis lupus arctos
(Arctic wolf)
Canis lupus baileyi
(Mexican wolf)
Canis lupus crassodon
(Vancouver Island wolf)
Where do viruses fit?
Are they alive?
Do they meet the requirements of living organisms?
These can be just
As bad as the others
Avoid at all costs!
How does a virus attack your body?