1biologyeocreviewnotes all

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 unitsglucose, 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: deoxyribonucleic acid; is a code for your physical (phenotype) traits

- PHYSICAL TRAIT

DNA & Genetics

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

– Phenotype ratio• Ex. 25% white bunnies, 75% black bunnies

– Genotype ratio• Ex. 25% bb, 50% Bb, 25% BB

F

F

f

f

FF Ff

Ff ff

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 togetherCross 2 heterozygous for color and height

(Green & Tall are dom; Yellow & Short are rec.)

TTGG TtGG TTGg TtGg

TtGG ttGG TtGg ttGg

TTGg TtGg TTgg Ttgg

TtGg ttGg Ttgg ttgg

TG tG Tg tg

TG

tG

Tg

tg

Red = tallBlack= short

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

2. 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 Environment Unique TraitBunny Rabbit Winter

Cactus Desert

Cheetah African Savanna

Chameleon Jungle

Peacock Mating Season

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: increase causes increase; decrease causes decrease– Ex. No shower for 2 weeks: smell from bacteria

growth increases on a daily basis

• Positive ≠ good

Positive Feedback

Negative or Positive Feedback??

Deforestation

Regulating Body Temperature (too hot OR cold)

Immune System Fighting Infection

Body is Hungry

P

P

N

N

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.