Transcript The Evolving Nature of Life

The Evolving Nature of Life
Ms. Johnson
Ms. Doncaster
Biology – Level 4
Standards
• SC.NL.04.01
– Describes how the biochemical and physical
nature of the earth determines how life evolves.
• SC.NL.04.02
– Uses the Darwinian theory to explain how
organisms must adapt to survive.
• SC.NL.04.03
– Describes the theory that life has evolved from
simple to more complex forms and that evolution
is an ongoing process.
Fact –OR- Fiction
• Lizards are more closely related to birds
than crocodiles.
• FACT. Genetically more similar to a bird!
Fact –OR- Fiction
• In a healthy population, everyone has the
same genes.
• FICTION. Variety can be a result of
mutations, which can be key to a
population’s survival
Fact –OR- Fiction
• Panda bears are NOT bears.
• FACT & FICTION. Most scientists classify
the giant panda as a bear, but the red
panda actually a type of raccoon.
Fact –OR- Fiction
• Dragonflies were once as large as
pigeons.
• FACT. Fossils reveal that giant dragonflies
inhabited earth 290 million years ago.
Fossils, Etc.
Ms. Johnson
Ms. Doncaster
Biology – Level 4
SC.NL.04.01
• Describes how the biochemical and physical
nature of the earth determines how life
evolves.
Hmmm…
• Biodiversity - variety and abundance of diff’t
species in a community.
• Change can create advantages/disadvantages
• Nat’l Disaster: Those who adapt
better (more traits), more likely
to survive
Numbers
• Current # of species: 5-30million
(only a fraction of what once was…)
• 99% of all organisms ever, now extinct
• Life – 4 billion years
Where did all the mammals go?
• Evolved 200mil yrs ago
• Who studies fossils?
– Paleontologist
• How are fossils studied?
– Anatomical, Molecular, Biogeographical
Fossil Vocab
• Fossil record – information stored in fossils
• T/F Are all fossils bones?
• Fossils found in sedimentary rock (sand/silt
settled at bottom of body of water)
– Compressed
– Water becomes dry land
• Fossils hard to find, vulnerable
to weather and erosion
Basilosaurus
• In the middle of the Sahara, hundreds of
whale skeletons
• Keep digging…Basilosaurus had legs!!
• Now in search of transitional fossils (fossils
between related fossils)
Transitional Fossils
• Hard to find
• Most DON’T lead to common ancestor, but
to “close cousins”
Vocab
• Homologous structures
– Different species, same characteristics
– Ex: Front fin of a whale (humerus, radius, ulna)
• Also found in other mammals: humans, wolves, sea
lions
• Sequencing
– DNA base or amino acid
– Molecular biologist compare proteins
Vocab
• Vestigial structures
– Inherited, but size reduced and often unused
• Ex) Pythons (hip/leg bones)
• Ex) Humans (appendix)
• Analogous structures
– Same function, different structures
• Ex) Bat, Bird, Insect
» WINGS!!
Vocab
• Phylogeny – History of an organism’s
development
• What current mammal is most closely
related to the whale?
• Yeah!!! Hippopotamus!!!
Fossil Dating
• Relative Dating
• Radiometric Dating
Relative Dating
• Older deposits found beneath more recent
• Geologic layers (with no/little geologic
activity)
• Two fossils. Same layer, ∴ Same time period
Relative Dating
• Rock layers do not determine age, but serves
to put layers in order of age
• Real age estimated by analyzing isotopes of
surrounding rocks
Radiometric Dating
• Isotope: Single atoms of same element with
different # of neutrons
– Weight changed
– Charge unchanged
• Some isotopes “radioactive”
• During decay, isotopes give off particles and
energy
Radiometric Dating
• Radioactive isotopes break down (decay)
matter at a constant rate
• Rates of decay: half-lives
– Half-live: the time it takes for ½ of the original
isotope to decay into a different isotope
– *Note* Every isotope has a
different, but known rate
Radiometric Dating – Half-Life
•
40K
decays to Ar
•
40K
half-life is 1.3bil years!!
Radiometric Dating
• Oldest fossil: ancient prokaryote
• Purpose: construct an evolutionary timeline
Eras, Periods, Epochs
• Remember…Life – 4 billion years
• Divided into Eras  periods  epochs
• Defined by fossil finds!!
Eras, Periods, Epochs
• Precambrian Era (590mil yrs ago)
• Paleozoic Era (248-590mil yrs ago)
– 6 periods…
• Mesozoic Era (65-248mil yrs ago)
– Triassic Period
– Jurassic Period
– Cretaceous Period
• Cenozoic Era (0.01-65mil yrs ago)
Standard 1
Is hIstory…
SC.NL.04.02
Uses the Darwinian
theory to explain how
organisms must adapt
to survive.
SC.NL.04.02 – Species

Species are unique

Species: interbreeding populations
SC.NL.04.02 – Variation

Within a species’ is a good amount of
variation
Variation: differences between individuals in a
population
 Subtle/Dramatic - (color, communication,
shape of teeth, number of offspring, territory
size, diet)

SC.NL.04.02 – Variation
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Most variations are genetic

Mutation
 Change
in gene sequence
 Ex: Red fox becomes silver

Recombination
 Allele
from “Mom” mixes with allele from “Dad”
SC.NL.04.02 – Adaptation
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Sometimes traits can be harmful
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Inherited traits will determine SURVIVAL
Sometimes traits can be beneficial
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ADAPTATION (increases survival rate)
SC.NL.04.02 – Adaptation
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Ex: Termites, Anteaters
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Small area, large population (termites)
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Competition: two populations trying to
occupy the same niche
SC.NL.04.02 – Adaptation
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Become suited to a certain niche
Niche: Role a population plays in an
environment
 Live? Eat? Raise Offspring? Predators?
Temp?

SC.NL.04.02 – Mr. Darwin &
Co.

1769 Charles Bonnet
Fossils didn’t look like modern lifeforms
 Catastrophes must have affected earth, and
life began again
 Coined the term “evolution” (change over
time)

Notes:
 Bonnet, earth catastrophes, “evolution”
SC.NL.04.02 – Mr. Darwin &
Co.

1809 Jean-Baptiste Lamarck
Challenged Bonnet
 Fossils were ancestors of modern life
1. Organisms strive for improvement
2. Principle of Use/Disuse
3. Only useful parts passed on
(Sorry Lamarck, your principle later
disproved by mice)
Notes:
Lamarck, Principle of Use DISproved!

SC.NL.04.02 – Mr. Darwin
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1831 Darwin travels on HMS Beagle

Studies plants/animals around the world
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Esp. Finches (diff groups had own niche)
Later, YES, really were 13 species
SC.NL.04.02 – Mr. Darwin
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1844 Thee Paper of All Papers!
1858 Finally published (scared to
publish)
On the Origin of Species by Means of
Natural Selection
SC.NL.04.02 – Natural
Selection
1.
Variation w/in populations

2.
Traits passed, but no info on genetics yet
Some variations are favorable

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Improves organism’s function and
reproduction
Ex) Fast ostriches outrun predators
SC.NL.04.02 – Natural
Selection
3.
Not all young produced in each
generation can survive

4.
Disease, starvation, predators
Individuals that survive and reproduce
are those with favorable variations
SC.NL.04.02 – Natural
Selection

Natural selection ultimately results in evolution

Gradualism: small genetic changes
occurring over time
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(But shouldn’t we see this in fossils?)
Punctuated Equilibrium: quick change
b/c of environment, etc.
SC.NL.04.02
Conflicting Theories
Help to Drive Research
about Evolution
SC.NL.04.03 – Simple to Complex
• Krakatoa– Volcano – 1883
– Destroyed island, left only ash
– No other land for 40km
– Now has new plants/animals…
SC.NL.04.03 – Speciation
• Evolution – process by which populations
change in response to their environment
• Sometimes organisms change so much
that they can’t interbreed with the ancestor
species, this means it IS a new species!!!
-SPECIATION-
SC.NL.04.03 – Speciation
• New species come when separated from
original population (i.e. by geography)
• They adapt (and biologically change) to
the new environment
SC.NL.04.03 – Types of Evolution
• 3 Types of Evolution
– Divergent
– Convergent
– Coevolution
SC.NL.04.03 – Divergent Evolution
• Same species evolve independently
– Ex. by geography
– or small group leaves the herd
• Ex. Brown bears migrated to ice,
adapted to become polar bears
• Remember…According to natural selection, the
animals with the advantageous traits survived and
passed them on to offspring.
SC.NL.04.03 – Convergent Evolution
• Unrelated species display similar features
• Can mislead scientists to think animals are
more similar than genetically are
– Cross-check with embryology, biochemistry
SC.NL.04.03 – Convergent Evolution
• Serval Cat vs. Maned Wolf
• Both have:
– Long ears to hear prey
– Eat rodents, lizards
– Long legs for chasing
SC.NL.04.03 – Convergent Evolution
• Paper clip experiment
• Think of a random use of a paperclip
(must be different from neighbor’s) and
submit.
SC.NL.04.03 – PaperClip Ideas
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Hold an ornament
Stress reliever
Nail cleaner
Body piercing
Prison shank
Contact Lens Remover
Nose plugger
Pick a lock
Electrical conductor
Spring
Paper flicker
Spear Insects
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Clean ears
Zipper replacement
Shootable object
Piercing Needle
Blow Gun Dart
Ring / Jewelry
Key Chain
Braces
Zipper replacement
Explosive
Opening windows
SC.NL.04.03 – PaperClip Ideas
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Guitar Pick
Shoelace Clip
Button
Nail Polish Remover
Earring
Sewing Needle
Pick to Unlock Doors
Earring
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Fake Nails
Nail Cleaner
Fish Hook
Key
Earring
Chew Toy RAWR!!!1
Ring / Jewelry
SC.NL.04.03 – Convergent Evolution
• Compare with others’
• Note that some people came up with same
ideas.
• Darwin had the same illustration for
convergent evolution. Darwin reviewed 2
people coming up with same invention
• Natural selection will produce similar
adaptations even though groups of
organisms are separate.
SC.NL.04.03 – CoEvolution
• Animals adapt not just to the environment,
but also with other plants and animals
• Coevolution: species that interact and
adapt to one another
• Even plants!
– Flower color/scent attracts
certain animals
– Hummingbirds!
SC.NL.04.03 – Adaptive Radiation
• Populations will fill empty habitats (&
niches)
• Adaptive Radiation:
many diverse species
from common ancestor
• Back to Darwin’s finches!
SC.NL.04.03 – Darwin’s Finches
• Different finches lived on different islands
(Galapagos Is.)
• All started on one island, then migrated
• Features link them
to original ancestor,
but not to each other
SC.NL.04.03 – Prokaryote Dev’t
• So, Did cells evolve the same way?
• Most scientists say the first cells were
heterotrophs
– They competed for organic compounds and
emitted CO2, and the strongest survived
• Variations occurred, autotrophs resulted
– Autotrophs didn’t compete for organics
SC.NL.04.03 – Prokaryote Dev’t
• Autotrophs not yet photosynthetic (plants
came later)
• Were probably anaerobes
– Bacteria, etc.
– Developed ability to tolerate oxygen and
surfaced
SC.NL.04.03 – Eukaryote Dev’t
• 3.5 bil yrs ago, heterotrophs (pro-k)
• 2.5 bil yrs ago, autotrophs (pro-k)
• 1.5 bil yrs ago, Eukaryotes!!
• How did eukaryotes develop inner
membranes?
– Infolding
– Endosymbiosis
SC.NL.04.03 – Eukaryote Dev’t
-Infolding• Cell membrane folded in
• Created compartments
– ER, Golgi, Vacuole
SC.NL.04.03 – Eukaryote Dev’t
-Endosymbiosis• Mitochondrion, Chloroplast types of
prokaryotes that were engulfed
• Remember…DNA?
• And then… eukaryotic cells led to
multicellular organisms
SC.NL.04.03 – Back to Genetics
• Individuals exhibit unique characteristics,
but evolution can only be measured in
terms of populationSSSS
• Gene pool: ALL genetic material in a
given population
• ALL genes for EVERY trait on EVERY
chromosome of a species
SC.NL.04.03 – Equilibrium
• Hardy-Weinberg principle– Under specific conditions, allele frequencies
remain constant (though don’t have to be the
same)
– (Feed roses same food, same amts of water
every year, will always be 50% white, 30%
pink, 20% yellow)
• However, there can be no favoritism or
competition for equilibrium to happen
SC.NL.04.03 – Distributions
• Normal
Number of Organisms
Normal Distribution Curve
SC.NL.04.03 – Distributions
• Directional
Directional Selection Curve
Number of Organisms
Normal
Directional
• No snow for a while, white rabbits now
prey and dark rabbits camouflaged
SC.NL.04.03 – Distributions
• Disruptive
Normal
Disruptive Selection Curve
Number of Organisms
Disruptive
• Dark ground, light green/white shrubs,
grey rabbits not protected
SC.NL.04.03 – Simple to Complex
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Artificial Selection
– Farmers choose most desirable traits to
breed
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Cows give more milk
Horses hardier
Wild mustard plant yields:
– Broccoli, cauliflower, brussel sprouts, cabbage
– Darwin suspects this also happens in nature
SC.NL.04.03 – Simple to Complex
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Geology
– Geologic change is slow and uniform.
Gradual change will influence plants/animals
SC.NL.04.03 – Simple to Complex
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Population Control
– When population is too large and supplies
are all used; war, starvation, and disease will
result
– So, not all offspring will survive
– Compete for food, water, space
And the STRONG will SURVIVE