Ecology
Big Ideas
Energy
• Energy flows through every ecological system
– Inputs = what goes into the ecosystem
– Outputs = what goes out of the system
Food Webs
• Increased
biodiversity
means a
healthier
ecosystem
Energy Transfer between
Trophic Levels
• 10% Energy Transfer
• Producers make up largest biomass
Bioaccumulations
• Toxins cannot be
removed and
increase in amount
between trophic
levels
Carbon Cycle
• Cycles carbon through the ecosystem
• Contains photosynthesis and cellular respiration
– Opposite chemical reactions
Nitrogen Cycle
• Cycles nitrogen
through the system
• Bacteria takes
nitrogen from the
atmosphere and
transfers it to
plants
Population Growth
• Populations will grow exponentially if there
are no limiting factors
Population Growth
• Populations will reach carrying capacity
because of limiting factors which include:
– Abiotic (non-living)
• Space & Water
– Biotic (living)
• Food & Predators
Population Density
• Population Density is the number of living
things in an area
– Example:
• 500 moose in 10 sq. miles = 50 moose per mile
General Ecology
• Non-native species usually DIE in a new
environment, some survive and take over if
they have no predators
Sustainability
• Maintaining resources for future use
• Choices we can make now that support
sustainability
– Substituting renewable (?) for non-renewable (?)
resources
– Recycling
– Using fewer resources
Macromolecules
• Carbohydrates: made of simple sugar units
glucose, galactose, fructose
• Lipids: fats, etc.
– Triglycerides made of glycerol
& 3 fatty acid tails
– Phospholipids made of
phosphate head & 2 fatty
acid tails
Macromolecules
• Proteins: made of amino acids
• Nucleic Acids – DNA & RNA: made of
nucleotides
Cell Structure & Function
Big Ideas
Main Cell Types
• Prokaryotes – no nucleus, nucleoid region of
DNA; bacteria
• Eukaryotes – DNA contained in nucleus,
membrane bound organelles; everything
except bacteria
Key Cell Components/Organelles
• Nucleus – DNA
• Ribosomes – Site of Protein Synthesis
• Endoplasmic Reticulum – assembly of lipids & finishing
work on proteins, etc.
• Golgi Apparatus – modifies, sorts and packages
proteins, etc. from ER for storage or release to outside
of cell.
• Mitochondria – breakdown of glucose into ATP
• Chloroplasts – convert sun energy into sugars
• Vacuoles & Vesicles – storage/movement of water, etc.
• Lysosomes – bread down of macromolecules and old
organelles.
Cell Boundaries & Movement of
Materials Across Them
• Cell wall – rigid structure outside cell
membrane for support, protection; found in
bacteria, fungi, plants
• Cell membrane – flexible barrier between
inside and outside of the cell
– Composed of phospholipid bilayer, proteins
– Selectively permeable – allows some things
in/out, but not others.
Cell Transport
• Passive Transport – no cellular energy used
– Diffusion – movement of materials from high to low
concentration
– Facilitated diffusion – diffusion of molecules through
protein channels (not directly through membrane)
– Osmosis – movement of water from high to low
concentration across a membrane (facilitated)
• Active Transport - requires cellular energy
– Movement of materials across the membrane from
low to high concentration
Photosynthesis and Cellular
Respiration
Big Ideas
Photosynthesis & Cellular Respiration
• Photosynthesis and cellular respiration are
opposite chemical reactions
• Photosynthesis: plants take carbon dioxide
(CO2) and water (H2O) and make glucose
(C6H12O6) and oxygen (O2)
– Plants make their own food!!!!!!!!!!!!!!!!
• Cellular Respiration: plants AND animals make
energy (ATP) by transforming glucose
(C6H12O6)and oxygen (O2) into carbon dioxide
(CO2) and water (H2O)
– CHEMICAL Energy in glucose is transformed into
the energy to live (ATP)
– Very similar to setting something on fire
(combustion), which releases carbon dioxide (CO2)
into the atmosphere
Be able to trace the path of a carbon atom
from air through photosynthesis,
cellular respiration and back to the air
Mitosis and Meiosis
Big Ideas
Mitosis & Meiosis
•
•
•
•
Division of Chromosomes in a cell
Chromosomes are made of DNA
DNA is replicated (copied) before each process
Each chromosome contains many sections of
DNA called genes which contain the code for a
protein
Mitosis
• Mitosis: produces two IDENTICAL cells from
one cell for growth and repair of body cells
• 2N cells produce 2N cells
Meiosis
• Meiosis: produces four UNIQUE sex cells for
reproduction
• Each cell is 1N – ½ the chromosomes of the body
cells
– Females: Eggs
– Males: Sperm
• Allows for differences (variation) in populations
• Fertilization restores the 2N number in offspring
Mitosis and Meiosis
DNA and Genetics
Big Ideas
DNA & Genetics
DNA: deoxyribonucleic acid; is a code for your
physical (phenotype) traits
- PHYSICAL
TRAIT
Traits
• Proteins: can be used to make body
structures, hormones and enzymes
– Enzymes act to speed up (catalyze) chemical
reactions in the body
• Ex. Digestion of food, making DNA, and regulating
glucose
Genetics Vocabulary
• Phenotype: What your physically look like
• Ex. Blue Eyes OR Brown Eyes
• Genotype: What your genes are
• Ex. Bb, bb, or BB
Vocabulary
• Dominant: Trait/gene that is shown
• Ex. BB = Brown Eyes
Bb = Brown Eyes
• Recessive: Trait/gene that is hidden by a
dominant gene
• Ex. bb = Blue Eyes
Bb = Brown Eyes
Vocabulary
• Heterozygous: different genes
– Ex. Bb for Brown Eyes
• Homozygous: same genes
– Ex. bb for Blue Eyes
• Punnett Square: used to predict offspring
– Ex. Two heterozygous bunnies are crossed; black fur is
the dominant trait
F
f
F
FF
Ff
f
Ff
ff
– Phenotype ratio
• Ex. 25% white bunnies, 75% black bunnies
– Genotype ratio
• Ex. 25% bb, 50% Bb, 25% BB
Earlobes (E)
A detached earlobe man (EE) has children with an
attached earlobe woman (ee).
1) What are the possible genotypes (gene
combination)?
2) What are the possible phenotypes (physical trait)?
• A heterozygous tongue roller (Tt) mates with a
non-tongue roller (tt), what percentage of
their children will be tongue rollers?
• What is the percent chance two heterozygous
tongue roller will have a non-tongue roller
offspring?
Dihybrid crosses – chance of inheriting 2 traits together
Cross 2 heterozygous for color and height
(Green & Tall are dom; Yellow & Short are rec.)
TG
TG
tG
TTGG
TtGG
Tg
TTGg
tg
TtGg
Red = tall
Black= short
tG
TtGG
ttGG
TtGg
ttGg
Tg
TTGg
TtGg
TTgg
Ttgg
tg
TtGg
ttGg
Ttgg
ttgg
Protein Synthesis
• Transcription
– The code in DNA is copied into mRNA
– This nucleotide sequence determines the sequence of amino
acids in the protein.
– mRNA leaves the nucleus and forms a “protein factory”
complex with rRNA called a ribosome.
• Translation
– The nucleotide sequence in mRNA is read 3 nucleotides at a
time – a codon.
– Each codon corresponds to a specific amino acid.
– tRNA brings the needed amino acid to the ribosome.
– The amino acids are bonded together to form a protein.
Transcription
Translation
Evolution
Big Ideas
Evolution
• Evolution: change over time
All living things are related
to a
COMMON ANCESTOR!!!
Evidence of Evolution
• Evidence:
1. Presence of Fossils found in rock layers
1. Homologous and Vestigial Structures
• Homologous: Similar Structures
• Vestigial: Unused structures; whale pelvis, human
wisdom teeth
Fossil Record
Homologous Structures
Evidence of Evolution
3. DNA Comparisons
• Humans and mice are 99% similar in DNA, so they are
closely related
4. Embryos
• Closely related organisms have similar embryos
DNA Comparisons
Embryos
Natural Selection
• Natural Selection: “survival of the fittest,
failure of the worst”
– Over reproduction sets up a struggle for existence
– Natural selection selects for variations in the
population (result of mutation & sexual
reproduction( that are adaptive
– The “goal” of life is to
survive and reproduce
(pass adaptive genes to
next generation)
• Mutations in DNA: can (not always) lead to
unique traits, which may help or hinder
survival!!
Organism
Bunny Rabbit
Environment
Winter
Cactus
Desert
Cheetah
African Savanna
Chameleon
Jungle
Peacock
Mating Season
Unique Trait
Mutations
Balancing Biological Systems
Homeostasis
• Homeostasis: regulation of systems to
maintain balance
• Two things can affect homeostasis
– Negative Feedback
– Positive Feedback
Negative Feedback
• Negative Feedback: increase causes decrease,
decrease causes increase
– Ex. Automatic Thermostat: if temperature
decreases in room, then the temperature
increases
–Negative ≠ bad
Positive Feedback
• Positive Feedback: increase causes increase;
decrease causes decrease
– Ex. No shower for 2 weeks: smell from bacteria
growth increases on a daily basis
• Positive ≠ good
Negative or Positive Feedback??
Deforestation
P
Body is
N
Hungry
Regulating Body
Temperature (too
hot OR cold) N
Immune System
Fighting Infection P
Choose two examples to complete a Negative
Feedback Loop AND a Positive Feedback Loop
• Identify what HOMEOSTASIS would be
• Explain the STIMULUS that tells us
homeostasis is not in balance
• Identify the CONTROL CENTER in the body (if
there is one) that recognizes the stimulus
• Explain what RESPONSE occurs
Other System Examples
• Boundaries, inputs and outputs in an ecosystem
(energy, biogeochemical cycles, population
dynamics, etc.)
• Interaction of enzymes, substrates and products
in biochemical pathway
• Organ systems
Scientific Method
• Reliability –
– Increased by repeating an investigation = more trials
• Validity –
– Increased by:
•
•
•
•
Adding more controlled variables
Improving measuring technique
Controlling for sample bias
Including an experimental control group
Different types of investigations
• Controlled experiments
– A lab investigation in which the values of all variables are kept the
same except for one that is changed from experiment to
experiment (manipulated variable) and one that is measured
(responding variable).
– Have experimental and control groups
– Include at least 3 levels of manipulated variable (if measuring
effect of fertilizer on plant growth, use 10 g., 20 g. and 30 g. of
fertilizer on different plants)
– Include at least 3 trials for each condition (can be repetitions or
more subjects).
• Field study
– A scientific study of free-living plants or animals in which the
subjects are observed in their natural habitat without changing,
harming, or altering the setting or subjects.
– No experimental and control groups
– May include sampling, observation, etc.