Download Biology Top 101

The Last of the Review Material:
Evolution, Classification, and the
Kingdoms
Evolution
The definition of evolution
• The change in gene frequencies in a
population over time.
• Populations evolve. Individuals don’t.
Individuals are stuck with the DNA they
have. All they can do is make the best
of it.
Abiogenesis
• The idea that life comes
from non-living material.
• Disproved by Redi who
showed flies come from
flies and Pasteur who
showed bacteria come
from bacteria.
Biogenesis
• The idea that life comes
from life.
Origin of Life
• Miller and Urey put
earth’s early gases in
a flask and sparked
them. Bonds broke,
new bonds formed.
Amino acids and
nucleotides were
created.
• Note that earth’s
early atmosphere
had NO O2 gas.
The Order of Life
• Given enough time it is believed that the
molecules formed in the “primordial soup” of
ancient earth arranged to form simple cells
and that these cells evolved to be more
complex. This is the order:
•
•
•
•
1st Anaerobic prokaryotes (bacteria)
2nd Photosynthetic prokaryotes (bacteria)
3rd Unicellular eukaryotes (protists)
4th Multi-cellular eukaryotes (fungus, plants,
animals)
Endosymbiotic Theory
• Eukaryotic cells evolved
from prokaryotes
• Early prokaryotes
engulfed other
prokaryotes and
developed symbiotic
relationships
• Evidence includes
mitochondria and
chloroplasts that have
prokaryotic type DNA
Darwin’s Theory of Evolution
by Natural Selection
• In a population,
members vary from
each other in some
way. Survival of the
Fittest states that
those with the best
adaptations survive
and reproduce,
passing on their
genes.
How might zebra in this population
vary from each other? What might
make a zebra more fit than
another?
Some might better smellers than others.
They would be more fit because they would
know sooner if a lion was nearby.
Adaptations
• Traits that
increases survival
• For example,
– Beaks that make it
easier to eat insects
– Bright flowers to
attract pollinators
– Vascular tissue in
plants to adapt to life
on land
Evidence for Evolution: Fossil
Record
• When fossils are lined
up according to age, a
progressive series of
changes can be seen.
• This provides evidence
that organisms can
change over time
Evidence for Evolution:
Biochemical Details
• Organisms that have
similar DNA
sequences and make
similar proteins are
more related and
share a more recent
common ancestor
than those who
don’t.
Evidence of Evolution:
Homologous Structures
• Homologous structures
are those that serve
different functions in
two species but
develop from similar
embryological
structures. The
species have a recent
common ancestor.
Note: analogous structures serve the same purpose for two
species but are very different in composition. The species do
not share much DNA and they do not share a recent common
ancestor (like fly wing and a bird wing)
Evidence of Evolution:
Vestigial Structures
• Vestigial structures are
structures that have no
obvious function in a
species.
• They provide evidence
that perhaps this
organism is related to
other species that use
the structure and that
the two species share a
common ancestor.
Whales have a pelvis
A pelvis is used for walking
Why does a whale have a
pelvis?
Speciation – Evolution of new
species
1.
2.
3.
4.
A population is separated
by a barrier (like a river)
The two groups can’t get
back together.
Each group changes
genetically in different
ways due to random
mutations and natural
selection favoring different
traits.
After enough changes
accumulate, the groups can
no longer breed and they
are considered two species.
New species develop fastest
in the following conditions
1. There is a lot of genetic variation in a
population.
2. The environment is rapidly changing.
Phylogenetic Trees
• These show who is more closely related to who.
• If two organisms share lots of DNA sequences, they
will be placed next to each other on the same branch.
What is the common ancestor to all of these?....A
What is the most recent common ancestor to J and K?....I
What is the most recent common ancestor to H and K?....G
Would you expect K to be more like J or more like M?....J
Give a species that went extinct…..C,D,L,H,O,P
Antibiotic and Pesticide
Resistance
• In a population of
bacteria or insects,
some are naturally
resistant to the
antibiotic or pesticide.
• The chemical kills the
non-resistant ones.
• The resistant ones
survive and reproduce
and now the next
generation cannot be
killed with the same
antibiotic/pesticide.
Coevolution
• Two organisms evolve in response to
each other
Ex. Flowering plants and
their pollinators
Flowers evolve to look
and smell a certain way
to attract pollinators.
Pollinators evolve senses
to pick up on the look and
smell.
Classification
Binomial Nomenclature
• System used to classify all organisms to
a scientific name consisting of two
parts.
• Uses Genus and species names
Canis familiaris - dog Canis lupus - wolf
To classify an organism…
• To get to the genus
and the species, you
pass through several
levels of classification
as shown on the right.
• The farther you
travel with another
organism, the more
alike you are to that
organism.
Duh…King Philip Came Over for Green Socks
You Try! Use the classification
to answer the questions.
• What is the broadest
category?
Domain
• List some organisms in
the same class.
Human, dog, lion
• Why do some of them
not make it to the order
level?
Only carnivores make it to this level
• Who are the two most
related species?
Dog and wolf
The classification system is
always undergoing change.
• Why?
– We are discovering new species.
– We are learning more about a species.
– We now sequence DNA instead of relying on
how organisms look externally.
For example, there used to be just two
kingdoms…..plants and animals. Then,
scientists learned fungus are not at all like
plants because they can’t make their own
food – so a third kingdom was made for
them. We currently have 6 kingdoms.
Dichotomous Keys
• Used to identify
organisms by
working through
questions with
two choices.
• What is
organism 7?
King cobra
• What is
organism 3?
House sparrow
3 Domains and 6 Kingdoms
Life is organized into
3 Domains and 6 Kingdoms
Domain
Description
Bacteria (Prokaryotes)
No nucleus – live everywhere
Archae (Prokaryotes)
No nucleus - live in extreme environments
Eukaryotes
Cells have a nucleus and lots of organelles.
Let’s learn more about the
kingdoms in the Eukaryote
Domain
Kingdom: Protists
•
•
•
•
•
•
•
•
Most live in ponds
Can be unicellular or multicellular
Can be autotrophic or heterotrophic
Reproduce mostly asexually
Some are animal like (protozoa),
some are plant like (algae)
Many have contractile vacuoles to
push out extra water flooding into
them
Some have eyespots that sense
light
Some can move with cilia (little
hairs), flagella (tail), or pseudopods
(fake feet).
–
–
–
How does A move?.....cilia
How does B move?.....pseudopods
How does C move?.....flagella
A.
B.
C.
A Protist of Note:
The Malaria Parasite
• A parasite lives on or within a
host. It benefits while
causing harm to the host.
• Ex. Plasmodium causes
malaria. It is spread by
mosquitoes. The parasite
gets into your liver and red
blood cells, causing damage
as it reproduces and grows.
• Remember from genetics
that those with the sickle
cell trait have some immunity
to malaria because the
parasite doesn’t like sickle
shaped cells.
Kingdom: Fungi
• Multicellular
eukaryotes
(yeast are the only
unicellular fungi)
• External Heterotrophs
• Reproduce asexually
and sexually
• They are important
decomposers – breaking
down dead things.
Kingdom: Plants
• Multicelluar eukaryotes
• Autotrophs
• Reproduce sexually and
asexually
• Have a cell wall made of
cellulose
Kingdom: Animals
• Multicellular eukaryotes
• Internal Heterotrophs
• Reproduce sexually and
asexually
• Lots of structures for
sensing and moving in
their environment
You Need to Know a Bit
More About Plants
Non Vascular Plants
• Also called
Bryophytes
• No true roots or
vascular tissue
causing them to be
small in size
• Must live in moist
environments
• Reproduce with
Ex. Mosses, liverworts
spores
Gymnosperms
• Vascular plants –
they have xylem
and phloem to
carry water and
food
• They have no
flowers, but they
do have seeds
• Ex. Conifers
(pine trees)
Angiosperms
• Flowering vascular
plants
• Flower is main
reproductive organ
• Seeds are enclosed
within a fruit
• Ex. Tulips,
deciduous trees
You Need to Know a Bit
More About Animals
Insects
• Transport through open
circulatory system
• Exchange gases through
spiracles and tracheal
tubes
• Most reproduce sexually
with internal
fertilization
• Develop through
metamorphosis
Annelids
(segmented worms)
• Transport through closed circulatory
system
• Exchange gases through moist skin
• Reproduce asexually and sexually with
internal fertilization
Amphibians
• Transport through a closed
circulatory system involving
a three chambered heart
• Gas exchange in young with
gills, adults use lungs and
moist skin
• Reproduce sexually with
external fertilization
• Develop through
metamorphosis
Mammals
• Transport though closed circulatory
system involving a four chambered
heart
• Gas exchange through lungs
• Reproduce sexually with internal
fertilization
• Young develop in a uterus and obtain
nutrients and oxygen through the
placenta and umbilical cord.
Where Do Viruses Fit In?
• Not considered living things
• All they are is a bit of nucleic material
surrounded by a protein coat.
• They can do nothing unless inside a host
cell.
• Ex. HIV, Influenza,
Smallpox
Our defense against viruses
is our immune system
*Remember that antibiotics only
work against bacterial
infections*
The Immune System
• The job of the immune system is to
recognize “self” from “non-self”. Your
immune system reads antigens (protein
name tags that identify cells). If your
immune system recognizes the name tag,
it leaves the cell alone. If not, the
immune system mounts an attack and
starts to produce antibodies – proteins
that will seek out and help destroy the
invading antigen.
Immunity
Passive Immunity
Active Immunity
• Antibodies are given into the
body
• Short term
• Such as when a mother
transfers antibodies to her
infant through breast
feeding
• Antibodies are acquired when
an immune response is
activated in the body
• Long term
• Ex. Vaccines are weak/dead
antigens that are introduced
to the body. They help a
person make antibodies and
create memory cells to
remember how to make those
antibodies in the future
How DO We Fight Viruses?
The Immune Response
B-cells
• Fight antigens
in body fluids
• B-cells make
antibodies
• Make memory
cells after
exposure to
antigen
T-cells
• Fight pathogens
inside living
cells
• May help Bcells to make
antibodies
• Make memory
cells after
exposure to
pathogen
Animal Behaviors
Innate Vs. Learned
• Innate behaviors are those that an
animal is born knowing how to do.
• Learned behaviors are those that animal
is taught to do or has learned as a
result of an experience.
Innate Behavior: Suckling
• Newborn mammals
know how to get milk
from their mothers.
Impala and baby
Innate Behavior: Imprinting
• After hatching
certain bird species
(ducks and geese)
will follow the first
moving thing they
see.
• This helps the
babies stay safely
with mom.
Innate Behavior: Migration
• Migration is when an
animal moves from one
place to another
usually due to weather
or to find food.
Migrations are
seasonal.
Innate Behavior: Hibernation
• When an organism
goes dormant in
response to cold.
• We all know bears
hibernate…..take a
look at these two
hedgehogs
hibernating!
Innate Behavior: Estivation
• When an organism
goes dormant in
response to heat.
This toad has been estivating in the desert in Arizona.
Learned Behavior: Conditioning
• Getting an animal to
do something they
normally wouldn’t
because they learn
to associate the
behavior with a
reward.
Pavlov’s Dogs – They salivate when a bell rings
because they learned to associate the bell with
meat. They have been conditioned.
Learned Behavior: Trial and
Error
When given choices,
animals can learn to
choose the option that
gives the best reward
Mice can learn to pull a
lever that delivers food.
They can learn to NOT
pull a lever that delivers
a mild electric shock.
Learned Behavior: Habituation
• Animals learn to
ignore a repetitive
stimulus because it
doesn’t provide
useful information
about their
environment.
This is Ms. Schultz’s dog, Loki. He ignores all cars driving by.
But when he hears her car, he comes running to the door.
Social Behavior: Courtship
• Communication between
individuals of the same
species for the
purposes of mating.
• Often chemicals called
pheromones are
released to attract
mates
• Sometimes courtship
Red crowned cranes dancing
dances are done.
Social Behavior: Territoriality
• Organisms will fight with their own
species (and with other species) for
their space. Below are male Beta fish
telling other males not to come any
closer.
Chemotaxis – Moving in
response to chemicals
• Positive – towards
the smell.
Ants follow smells
to get to food
• Negative – away
from the smell.
Prey are alerted by the
smell of a predator that
is it time to move away
Phototaxis – moving in
response to light
• Positive – towards
the light
Moths move to lights
• Negative – away
from the light
Earthworms avoid light
and burrow underground