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
DNA and Genetics
Big Ideas
DNA & Genetics
DNA: deoxyribonucleic acid; is a code for your
physical (phenotype) traits
- PHYSICAL
TRAIT
• 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
Punnett Square Practice:
Small Whiteboards
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 blue eyed male mates with a blue eyed
female, what color eyes could the offspring
have?
– Blue eyes are recessive
• A heterozygous tongue roller (Tt) mates with a
non-tongue roller (tt), what percentage of
their children will be tongue rollers?
Ear Wiggling (W)
• What is the probability
(percentage) that two
homozygous recessive
people will have a child
that can wiggle their
ears?
• Can move ears = Dominant
(although this may be
variable)
• Can’t move ears =
Recessive
• A homozygous recessive female with freckles
(f) mates with a homozygous dominant male
without freckles (F), what genotypes could
their offspring have?
• What is the percent chance two heterozygous
tongue roller will have a non-tongue roller
offspring?
Mitosis and Meiosis and
Evolution
Big Ideas
Mitosis
• Mitosis: produces two IDENTICAL cells from
one cell for growth and repair
Meiosis
• Meiosis: produces four UNIQUE sex cells for
reproduction
– Females: Eggs
– Males: Sperm
• Allows for differences (variation) in populations
Mitosis and Meiosis
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”
– The “goal” of life is to survive and reproduce
– Based on ability to survive in environment
• 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
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