Biodiversity and Evolution

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Biodiversity
and Evolution
DO NOW FRIDAY
 When
a fossil is examined for the amount
of parent and daughter atoms present, it
was found that there are 10 grams of
parent isotope and 70 grams of daughter
isotope. If the half life of the parent
element is 12,500 years, how old is this
fossil?
Learning Targets
 Determine
decay.
absolute age using radioactive
DO NOW MONDAY
 What
is biodiversity?
 Why do you think it is important to learn
about biodiversity?
Learning Targets
 Define
biodiversity.
Which do you like better?
A
B
Which do you like better?
A
B
Which do you like better?
A
B
Which do you like better?
A
B
Which do you like better?
A
B
What is biodiversity?
 -the
variety of life across all ecological
levels of organization
Biodiversity includes:
 Genetic
diversity: differences in DNA
among individuals/species
 Species diversity: # or variety of species
in a given area
 Ecosystem diversity: variety of
ecosystems/habitats/communities
Species Diversity
 Most
commonly used measure of
biodiversity in an area
 Occurs through speciation: process by
which new species are generatedhappens over a long period of time
 Extinction DECREASES species diversity
Genetic Diversity
 Differences
in DNA due to mutations, sexual
reproduction, etc.
 Provides the raw material for evolution
(adaptations)
 Reduced genetic diversity means reduced
ability to adapt to environmental change
and reduced ability to survive.
 More genetic diversity means a population
has a better chance of evolving to survive
an ever-changing environment
DO NOW TUESDAY
 Explain
how genetic diversity affects a
population’s ability to survive a changing
environment.
Learning Targets
 Explain
Darwin’s hypothesis for differences
between similar species.
 Define natural selection.
 Explain how natural selection leads to
evolution.
Why is biodiversity important?
 Species
are interconnected- they depend
upon one another- we depend upon
them
Why is biodiversity important?
 Diversity
is important to species and
population survival
 Example: Northern Elephant seals hunted
almost to extinction. Now their population
has rebounded due to laws being passed,
but they still lack genetic diversity. Why is
this such a concern?
Why is biodiversity important?
 Medical,



industrial, and agricultural uses
¼ of all drugs come from plants and almost
all antibiotics come from fungi
Many compounds used for industry come
from plants and animals
All human food comes from other living
things
Why is biodiversity important?
 Ethics,


aesthetics
Many believe all organisms have a right to
survive
Make the world a pretty and more
enjoyable place to live
 ecotourism
Video
 Biological
Evolution

Watch video closely and complete
handout as you watch.

http://www.discoveryeducation.com
What is Evolution
 Means
“change over time”
 Biological evolution means a change in a
populations gene pool over time.
 A populations gene pool includes all of
the genes that are present in the
population.
Darwin’s Observations
 December
1831, Charles Darwin set sail
from England on a five year trip around
the world.
 He observed plants and animals he had
never seen before.
 This observation led him to develop the
theory of evolution by natural selection.
Darwin’s Observations
 Darwin’s
observations included:
Species
diversity- lots of different species
of organisms on different islands of the
Galapagos (Ex. Finches)
 Species: a group of similar organisms
that can mate with each other and
produce fertile offspring
Remains of ancient organisms (fossils)
Fossils
Galapagos Organisms
 Darwin’s
drawings
 Identify some specific
differences in these
finches’ beaks.
 These finches live on
different islands in
the Galapagos.
 Different islands have
different food sources
available to the
finches
Evolution
 Darwin
reasoned that plants or animals
that arrived on the Galapagos Islands
faced environmental factors that were
different from those on the mainland.
 Darwin hypothesized that the species
gradually changed (evolution) over
many generations and became better
adapted to the new environments.
Scientific theory
 Scientific
theory: A well-tested concept
that explains a wide range of
observations
 Darwin concluded that organisms on the
Galapagos Islands had changed over
time, but did not know HOW the
changes had happened.
Selective Breeding
 Humans
have used selective breeding to
produce sheep and pigeons that fit
certain criteria.
 Darwin thought that a process similar to
selective breeding might happen in
nature.. But what process would push
this selective breeding in nature?
Natural Selection
 Darwin
proposed that evolution occurs
in nature through natural selection
(individuals that are better adapted to
their environment are more likely to
survive and reproduce than other
members of the same species) in the
book called, On the Origin of Species by
Natural Selection.
Natural Selection
 Competition
– since food and other
resources are limited, the members of a
species must compete with each other
to survive.
 Selection – some variations make
individuals better adapted to their
environment, making them better
competitors and more likely to survive
and reproduce
Natural Selection
 Selection
(cont’d) – Darwin proposed
that, over a long time, natural selection
can lead to change. Helpful variations
may gradually accumulate in a species,
while unfavorable ones may disappear.
Adaptations
a
trait that makes an organism a
better competitor and helps an
organism survive and reproduce in
its environment
 Ex: milkweed – poisonous or have a bad
taste – avoid being eaten
 Ex: some plants have bright colored
flowers – attract insects
Evolution Online
A
demonstration...
DO NOW THURSDAY
 What
adaptations do you see in the
pictures below?
A)
Learning Targets
 Explain
Darwin’s hypothesis for differences
between similar species.
 Define natural selection.
 Explain how natural selection leads to
evolution.
Darwin’s Theory of Natural
Selection occurs in four steps:




Overproduction
Variation
Competition
Selection
1. Overproduction

Each species produces more offspring
than can survive
2. Variation
 Each
individual has a unique
combination of inherited traits.

Adaptation: an inherited
trait that increases an
organism’s chances of
survival and
reproduction in its
environment
Why is Variation Important?


Because the environment changes.
The more variation (diversity) within a
species, the more likely it will survive


EX: If everyone is the same, they are all
vulnerable to the same environmental
changes or diseases
The more variation (diversity) of types of
species in a habitat, the more likely at
least some will survive

EX: Dinosaurs replaced by mammals
Which community has a better chance of
surviving a natural disaster?
Community A
Community B
3. Competition
 Individuals

COMPETE for limited resources:
Food, water, space, mates
 Natural
selection occurs through “Survival of the
fittest”

Fitness: the ability to survive and
reproduce
 Not
all individuals survive to adulthood
4. Natural Selection
 The
individuals with the best traits / adaptations
will survive and have the opportunity to pass on
it’s traits to offspring (reproduce).


Natural selection acts on the phenotype (physical
appearance), not the genotype (genetic makeup)
Ex: When a predator finds its prey, it is due to the
prey’s physical characteristics, like color or slow
speed, not the alleles (BB, Bb)
Charles Darwin Game of
Evolution
 http://www.sciencechannel.com/games-
and-interactives/charles-darwin-game/
DO NOW WEDNESDAY
 How
does embryo development serve as
evidence for evolution?
Learning Targets





Recognize pictorial data patterns of
embryological development across multiple
species.
Describe how the fossil record documents the
existence, diversity, and change of life forms.
Identify anatomical similarities and differences
between modern and fossil organisms.
Identify anatomical similarities and differences
in modern organisms.
Define and identify homologous structures.
Evidence for Evolution:





Embryology
Fossil Record
Homologous Body Structures
Vestigial Organs
Biochemical Evidence
Embryology

Embryology: embryos of all vertebrates
are very similar early on
The Fossil Record

Fossils: a record of the history of life on
Earth
Archaeopteryx


Transition species
Missing link between
reptiles and birds
Fossils of organisms found on
many different continents prove
that all of the continents used
to be joined at some point
in the past. (Pangea)
Homologous Body Structures


Homologous Body
Structures: similar
anatomy in different
types of animals
because of common
ancestor
forearm
bones of human, bat,
bird, dolphin
Homologous Body Structures
Vestigial Organs

Vestigial Organs: “leftover” traces of evolution
that serve no purpose
Biochemical Evidence

Biochemistry: DNA with more similar
sequences suggest species are more
closely related

EX: Humans and chimpanzees share more
than 98% of identical DNA sequences
DO NOW THURSDAY
 What
are homologous structures? Give
an example.
Learning Targets

















4.1
4.2
4.3
4.4
4.5
5.1
5.2
5.3
Identify a
.
Identify a
.
Identify a
.
Identify
.
Identify
.
Explain
using
.
Identify the sequence of rock layers using the
Determine the
of fossils/rock layers using
.
6.1 Define
.
6.2 and 6.3 Identify anatomical similarities and differences in modern
organisms.
7.1 Describe how
documents the existence, diversity,
and change of life forms.
Define
.
Explain
.
Explain
for differences between similar species.
Identify
.
Recognize pictorial data patterns of
across
multiple species.
Define and identify
.
What is the adaptation?
Coral Snake
(Poisonous)
Milk Snake
(Not
poisonous)
What is the adaptation?
What is the adaptation?
What is the adaptation?
What is the adaptation?
What is the adaptation?
Stick Mantid
What is the adaptation?
Flower Mantid
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