LIFE SCIENCE
What You Need to Know
Explain that cells are the basic units of structure and
function of living organisms, that once life originated
all cells come from pre-existing cells, and that there
are a variety of cell types.
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Explain that living cells: a. are composed of a small
number of key chemical elements (C, H, O, N, P, and
S); b. are the basic unit of structure and function of all
living things; c. come from pre-existing cells after life
originated; and d. are different from viruses.
Compare the structure, function, and interrelatedness
of cell organelles in eukaryotic cells (e.g. nucleus,
chromosome, mitochondria, cell membrane, cell wall,
chloroplast, cilia, flagella) and prokaryotic cells.
Cell Theory
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Cells come only from other cells. The old theory was
called spontaneous generation and was disproved by
Redi.
Cell theory began with the invention of the
microscope by van Leeuwenhoek in the 1600s.
Hooke called the “building blocks of living things”
cells.
There are two basic cell types: prokaryotes and
eukaryotes that contain membrane-bound organelles.
Viruses are not living and have only nucleic acids in a
protein “coat.” They can only reproduce inside a
living cell.
Cell Organelles
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Only eukaryotic cells have these:
a. nucleus – directs all cell functions
b. nucleolus – makes ribosomes
c. cell wall – found only in plant cells, hold cell together
d. ribosomes – make proteins following DNA directions
e. cytoplasm – clear gel inside the cell
f. endoplasmic reticulum – site of cellular chemical reactions
h. Golgi apparatus – sorts and holds proteins until needed
i. vacuoles – temporary storage of materials
j. lysosomes – contain digestive enzymes
k. mitochondria – transform energy for the cell
l. chloroplasts – capture light energy and convert to chemical
m. centrioles – help with cell division
n. cilia and/or flagella – help cell move, if there at all
Pictures of Cell Types
All cells fall into one of the two major classifications of prokaryotes and
eukaryotes. Prokaryotes were here first and for billions of years were the
only form of life. Eukaryotes are more organized and appeared later.
There are some of both on Earth today.
Explain the characteristics of life as indicated by
cellular processes and describe the process of cell
division and development.
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Explain the characteristics of life as indicated by
cellular processes including: a. homeostasis; b.
energy transfers and transformations; c. transportation
of molecules; d. disposal of wastes; and e. synthesis
of new molecules.
Summarize the general processes of cell division and
differentiation, and explain why specialized cells are
useful to organisms and explain that complex multicellular organisms are formed as highly organized
arrangements of differentiated cells.
Cellular Processes
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There are many cellular processes. We will focus on:
a. homeostasis – regulation of internal environment to help
guarantee survival
b. energy transfers and transformations – making food from
light, extracting energy from food (respiration, photosynthesis,
fermentation, digestion)
c. transportation of molecules – supply cells with nutrients
d. disposal of wastes – removal from cells or organisms
e. synthesis of new molecules – proteins made in ribosomes,
following instructions from DNA
Cell Division
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There are two types of cell division:
a. Meiosis – Meiosis is the process that shuffles the genes
around. Plants do it, animals do it, and even fungi do it
(sometimes). Instead of creating two new cells with equal
numbers of chromosomes (like mitosis), the cell does a second
division soon after the first. That second division divides the
number of chromosomes in half. This is sexual reproduction.
b. Mitosis - The big idea to remember is that mitosis is the
simple duplication of a cell and all of its parts. It duplicates its
DNA and the two new cells (daughter cells) have the same
pieces and genetic code. Two identical copies come from one
original. Start with one; get two that are the same. This is
asexual reproduction.
Both types of cell division are very important.
Explain the genetic mechanisms and
molecular basis of inheritance.
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Illustrate the relationship of the structure and function
of DNA to protein synthesis and the characteristics of
an organism.
Explain that a unit of hereditary information is called
a gene and genes may occur in different forms called
alleles (e.g., gene for pea plant height has two alleles,
tall and short).
Describe that spontaneous changes in DNA are
mutations which may or may not be passed on to
future generations.
Use the concepts of genetics to explain inheritance.
Hereditary Information
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Mendel was one of the first geneticists, working with pea
plants.
Chromosomes are made of genes and genes can be of different
types, called alleles. Alleles determine traits.
Genes can be dominant or recessive or neither.
Some traits are determined by more than one gene. Some
diseases are genetically determined, like cystic fibrosis, etc.
Genotype is your genetic code; phenotype is the outward
appearance of those genes or the trait itself.
Homozygous is when an organism possesses 2 identical genes
for a trait; heterozygous is one of each gene. (TT or Tt).
Sex-linked traits, such as red-green color blindness and
hemophilia, are carried on the sex chromosomes (X and Y in
humans).
Mutations
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Mutations are changes in DNA sequence. They can be
caused by errors in replication, transcription, cell
division, or external agents (such as radiation,
chemicals, and even high temperatures).
Mutations are especially significant if passed from
one generation to another.
Mutations, by effecting the DNA sequence, can also
affect the ability to make important proteins.
It is difficult, or impossible, to repair damaged DNA.
Tracing Inherited Traits
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Punnett squares are often used.
Pedigrees can also be used.
Explain the flow of energy and the cycling of matter
through biological and ecological systems (cellular,
organismal, and ecological).
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Describe how matter cycles and energy flows
in living systems and between living systems.
Describe how cells and organisms acquire and
release energy.
Explain that living organisms use matter and
energy to synthesize a variety of organic
molecules and to drive life processes.
Energy and Food Webs
As predators eat
prey and
consumers eat
producers,
energy is
transferred
from one
organism to
another.
What happens
when the
chain is
disrupted? For
instance, all
the snakes are
killed by a
disease. How
does this
affect the
other living
things?
Explain how evolutionary relationships contribute to
an understanding of the unity and diversity of life.
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Describe that biological classification
represents how organisms are related with
species being the most fundamental unit.
Explain that variation of organisms within a
species increases the likelihood that at least
some members of a species will survive under
changing conditions.
Relate diversity and adaptation to structures
and their functions in living organisms.
Classification
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There are 6 Kingdoms: Eubacteria, Archaebacteria,
Protists, Fungi, Plants, and Animals.
Each Kingdom is then broken down into phylum,
class, order, family, genus, and species. Animals in a
species are the MOST related to each other.
Scientific names use the genus and species names
(Genus species). Canis rufus is a red wolf, Canis
latrans is a coyote, and Canis lupus is a grey wolf.
They are different species because of physical traits.
Usually one species cannot breed with other species
and produce fertile offspring.
Survival of the Fittest
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Genetic changes can be caused by mutation,
genetic drift, and gene flow.
Some genes protect organisms from one thing
but endanger them in other ways. Presence of
sickle cell anemia gene protects people from
malaria. Where the person lives may determine
which is better.
Explain the structure and function of ecosystems
and relate how ecosystems change over time.
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Explain how living things interact with biotic and
abiotic components of the environment.
Relate how distribution and abundance of organisms
and populations in ecosystems are limited by the
ability of the ecosystem to recycle materials and the
availability of matter, space and energy.
Conclude that ecosystems tend to have cyclic
fluctuations around a state of equilibrium that can
change when climate changes, when new species
appear as a result of immigration or when species
disappear.
Ecosystems
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Ecosystems vary in size. They can be as small as a puddle or
as large as the Earth itself. Any group of living and nonliving
things interacting with each other can be considered as an
ecosystem.
Within each ecosystem, there are habitats which may also
vary in size. A habitat is the place where a population lives. A
population is a group of living organisms of the same kind
living in the same place at the same time. All of the
populations interact and form a community. The community
of living things interacts with the non-living world around it to
form the ecosystem. The habitat must supply the needs of
organisms, such as food, water, temperature, oxygen, and
minerals. If the population's needs are not met, it will move to
a better habitat. The processes of competition, predation,
cooperation, and symbiosis occur.
Biomes are ecosystems where several habitats intersect.
Describe how human activities can impact the
status of natural systems.
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Describe ways that human activities can
deliberately or inadvertently alter the
equilibrium in ecosystems. Explain how
changes in technology and biotechnology can
cause these same kinds of changes.
Illustrate how uses of resources at local, state,
regional, national, and global levels have
affected the quality of life.
Describe a foundation of biological evolution as the
change in gene frequency of a population over time.
Explain current and historical developments.
Describe how scientists continue to investigate and
analyze aspects of evolutionary theory.
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Recognize that a change in gene frequency is a
foundation for evolution.
Explain about natural selection.
Describe some historical developments that
occurred in evolutionary thought.
Describe how scientists continue to investigate
and analyze aspects of evolutionary theory.
Evolutionary Thoughts
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Things change. The process of cars changing over the
past 100 years can be thought of as an evolution in
engineering. When an organism changes over many
generations, it might be better suited to live, or more
likely to die.
If the change was that you are a 500-pound bird with
little tiny wings and little tiny legs, chances are you
wouldn't move around too well. One day you might
run out of food and die or be eaten.
Mutations, genetic drift, and migration may help this
process of evolution.
Fossil evidence shows changes in organisms over
time.
Convergent Evolution
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CONVERGENT EVOLUTION
This is when two totally different species develop
similar traits. Outside natural factors create a situation
where that skill is a benefit. For example, you are a
plant and I am an animal. We both have animals
hunting us and eating us. We need protection. So we
both develop spines to poke the hunters. The spines
are made in different ways but do the same job. You
are a cactus and I am a porcupine.
Divergent Evolution
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DIVERGENT EVOLUTION
We start as the same species, but then as more
generations develop, my group becomes good at one
thing and yours at another. Bird beaks are a good
example for this one. One species of bird can develop
in different directions depending on what type of food
it eats. Their beaks develop different shapes after
many generations. Charles Darwin used bird
development in many of his scientific papers.
Explain how natural selection and other
evolutionary mechanisms account for the unity and
diversity of past and present life forms.
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Analyze how evolutionary mechanisms provide a
scientific explanation for the diversity and unity of
past and present life forms.
Explain that life on Earth is thought to have begun
about 4 billion years ago. During most of the history
of Earth, only single celled organisms existed but
once cells with nuclei developed, increasingly
complex organisms evolved.
Summarize the historical development of scientific
theories and ideas, and describe emerging issues in
the study of life sciences.
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Use historical examples to explain how new
ideas are limited by the context in which they
are conceived.
Describe advances in life sciences that have
important long-lasting effects on science and
society.
Analyze and investigate emerging scientific
issues, such as genetically modified food, stem
cell research, and cloning.
Biotechnology
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Some examples of biotechnology are:
a. imaging (X-rays, scans, etc)
b. genetic engineering
c. genome projects
d. newer and better microscopes
e. stem cell research
f. cloning
g. genetically modified foods.