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Science
Notebook
Science STAAR
STAAR Notebook
Biology
- Category
33
Biology
- Category
Biological Evolution and Classification
Taxonomy
• Classification Levels:
• Test Taking Hint: you have to know the order,
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memorize a mnemonic!!!
In scientific notation, the first name is always the genus,
the second name is always the species.
– Example – Homo sapien
Genus
Species
STAAR Question
Which of the following is the most specific
group used to classify organisms?
Hint:
A Kingdom
B Class
C Genus
D Order
Why is Taxonomy Important?
• Taxonomy provides order by accurately & uniformly
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naming organisms
Helps scientists identify animals which are similar to
each other.
Prevents misnomers such as starfish & jellyfish that
aren't really fish
When new animals are discovered, there is a common
way of naming them so ALL people understand.
Uses same language (Latin or some Greek) for all names
All other animals share at least a genus; only humans
have there own genus and species.
Taxonomy
• The more levels that organisms are in
together the more closely related they are.
– For example the bullfrog, Rana catesbeiana is
most closely related to northern leopard frog,
Rana pipiens because they have the same
genus name.
Taxonomy Glossary
KNOW THESE TERMS!
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Vertebrate=backbone
Invertebrate=no backbone
Segmentation=repetitive segments (ex: worm)
Unicellular=single celled organism (ex: bacteria)
Multicellular=many cells (ex: cat)
Autotrophic=make their own food (ex: plants)
Heterotrophic=can’t make their own food (ex: animals)
Mobile=move
Immobile=can’t move
Bilateral symmetry=mirror images (ex: butterfly)
Radial symmetry=duplicate body parts (ex. Starfish)
The Six Kingdoms
1. Archaebacteria – unicellular (one-celled) prokaryotes that often live
in extreme environments. Some are autotrophs (make their own food),
some are heterotrophs (consume their food). Examples: bacteria that
live in hot springs.
2. Eubacteria – unicellular prokaryotes that may or may not make their
own food. Examples: bacteria that cause strep throat.
3. Protista – mostly one-celled eukaryotes. However, there are a few
protists that are multicellular. Protists may be autotrophs or
heterotrophs. Lack tissues like roots or leaves. Examples: amoebas,
slime molds, and algae.
4. Fungi – most are multicellular and eukaryotes, although there are a
few unicellular fungi. All fungi are heterotrophs (absorb their food) with
cell walls. Examples: mushrooms, yeasts, and molds.
The Six Kingdoms (con’t)
5. Plantae – multicellular eukaryotes. They have
cell walls and specialized tissues and organs.
Plants are autotrophic by performing
photosynthesis. Examples: mosses, ferns, trees,
and grasses.
6. Animalia – multicellular eukaryotes. They are
heterotrophs (consume their food). They have
specialized tissues and organs. They are motile
(can move around). Examples: worms, insects,
fish, birds, and mammals, humans.
STAAR QUESTION
Evolution
Definition – change in a population over
time.
Evidence of evolution:
1. Fossils – traces or remains from an
organism that lived long ago.
2. Biogeography – geographic distribution of
organisms
3. Homologies – similarities between organisms
show common ancestry, examples:
a. Anatomical similarities – structures that
organisms have in common.
a.
vestigal structures - structures that are no longer
functioning but are still present.
Evolution
– Evidence of evolution (con’t):
b. Molecular similarities –
-DNA Sequences (strongest piece of evidence) – comparing the
amino acid sequences of different proteins to compare the
relationships
- For example, Cytochrome c is a protein found in all aerobic
organisms.
c. Physiological Similarities –
- Homologus structures – structures that are similar in
organisms but have different functions.
i.e. bones in the arms of birds, mammals, and amphibians
d. Developmental similarities –
-Embryology – study of embryos. Scientists conclude that since
many organism’s embryos look similar, that we evolved from a
common ancestor.
STAAR Question
The limbs of several organisms are shown in the
illustrations below. Scientists sometimes compare the limbs
of these organisms to look for evidence of common
ancestry.
These limbs provide evidence of common ancestry because
they –
A have the same basic structure
B perform the same function
C are the same size
D are parts of mammals
STAAR Question
Natural Selection
• A mechanism for
evolution.
• Traits that help an
organism survive in a
particular environment
are “selected” for in
natural selection
• A chance mutation in an individual can lead to
natural selection in a population and increase the
frequency of those genes.
STAAR Question
Some organisms have genes that improve their
ability to survive and reproduce. If the genes also
help their offspring survive and reproduce, then
which of the following will most likely increase?
A The frequency of the genes in one individual
B The frequency of the genes in the population
C The number of genes in one chromosome
D The number of genes in the species
Natural Selection
• Natural selection rests on three
facts:
1. Organisms produce more offspring than
can survive, ex: 1 out of 1,000 sea turtle
hatchlings will make it to adulthood.
2. Individuals vary in their characteristics
due to genetic variation (differences in
DNA that produce different traits in the
organism).
3. Many characteristics are inherited by
offspring from their parents, ex: genes
that improve an organisms ability to
survive and reproduce.
Types of Natural Selection
• Long term survival of any species is possible only if the
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organisms can reproduce successfully.
Adaptation – how organisms change to fit their
environment, ex: mimicry – scarlet king snake and the
eastern coral snake. Which one is poisonous?
• Genetic drift – change in the frequency of alleles in a
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population.
Speciation – the process by which new species arise.
Extinction – the end of a species.
Changes in a single organism:
1. Mutations – change to
the DNA of an organism;
can be passed to offspring
and add variation to the
population
2. Recombination - Crossing
over of genetic material
during meiosis; creates new
sequences of DNA
Changes in a population:
1. Gene Flow –
organisms migrate to
other populations. Ex:
this new bug will add
variation to the new
population.
2. Genetic drift –
random changes in
the allele frequencies
in a population
STAAR QUESTION
Why is natural selection important?
• The earth’s environment is constantly changing, so animals must
change with it.
• Changes to the animal can be slight, but if they help the animal
survive, it will be more likely to reproduce and pass on that gene.
– Example: Wooly mammoth and elephant
Questions:
1. What is the difference between a wooly mammoth and an elephant?
2. How were their environments different?
3. Why did the mammoth not survive after the ice age?
STAAR Question
Traits that enable an organism to survive
and reproduce in its environment are known
as -
A Mutations
B Variations
C Adaptations
D Speciation