le year in review
DESCRIPTION
This is a presentation I did as a year-end review for my middle school life science students.TRANSCRIPT
The Living Environmentthe year so far ...
What does it mean to be alive?
Characteristics of Life
MRLSTRNGR
MetabolismRegulationLocomotionSynthesisTransportRespirationNutritionGrowthReproduction
Characteristics of Life
Cells are the building blocks of life
Every organelle has a job to do
And they each help to maintain homeostasis
Ecology
Ecology is all about relationships
Biotic Factors depend upon Abiotic Factors
Everything eats everything else
Energy Flows Through the System
Things move from the simple to the complex
Nutrients Come and Go
and Biodiversity is King
Genetics
4 Parts of Genetics
Inheritance
Rules of Inheritance
There are different versions of each trait.
Traits are inherited from your parents.
You inherit one version of each trait from each of your parents.
You need both versions of the trait to show (express) the trait* (*except not always).
Not all versions of a trait are equal.
Inheritance Concepts
Dominant - only one version of the gene needs to be present for the trait to be expressed.
Recessive - both versions of the gene need to be present for the trait to be expressed.
Incomplete dominance - a blending of the two versions of the trait.
Co-dominance - both versions of the traits are expressed.
Genes and Chromosomes
Chromosomes are made of DNA.
Humans have 23 pairs of chromosomes.
Genes are sections of a particular chromosome.
Each gene is a recipe for a specific protein.
The recipe is a string of nitrogenous bases.
Any change to the recipe is called a mutation.
The structure of DNA
DNA is a double helix or twisted ladder.
Backbone - sugar (deoxyribose) and phosphate
Rungs - nitrogenous basis (Adenine, Thymine, Guanine, Cytosine)
RNA Structure
RNA is a single-stranded molecule.
Backbone - sugar (ribose) and phosphate
Rungs - nitrogenous basis (Adenine, Uracil, Guanine, Cytosine)
DNA Replication
The DNA molecule unzips (thanks to enzymes).
Each strand builds a complimentary strand.
One becomes two.
Protein Synthesis, part 1
A section of the DNA is unzipped (again thanks to enzyme action).
A strand of mRNA makes a copy of the recipe for a particular protein.
The mRNA leaves the nucleus and attaches to a ribosome.
Protein Synthesis, part 2
The mRNA is attached to the ribosome.
Strands of tRNA (with only 3 bases) pair up with the strand of mRNA.
tRNA carries amino acids, which bond together to form proteins.
When complete, the mRNA and tRNA move on to make more proteins, the protein goes to do whatever it is supposed to do.
Mitosis
Type of cell division used for growth and repair.
One cell becomes two cells.
The parent and offspring are genetically identical.
Mitosis happens in phases (IPMAT).
Mitosis
Meiosis
Type of cell division used to make sperm or egg cells (gametogenesis).
One cell becomes four cells.
The parent and offspring are genetically different, and the offspring cells have half the number of chromosomes as the parent (haploid).
Meiosis happens in phases (IPMAT X 2).
Meiosis
Evolution
Species Change Over Time
Evidence for Evolution
Fossil Record
Homologous Structures
Analogous Structures
Vestigial Structures
Embryonic Development
Fossil Record
Homologous and Analogous Structures
Vestigial Structures & Embryonic Development
Why it works
How it works
Reproduction
Asexual Reproduction
Offspring and parents are genetically identical.
Allows for the least amount of genetic variation.
There are many types.
Sexual Reproduction
Offspring and parents are genetically different.
Allows for the most amount of genetic variation.
Fertilization and embryonic development can occur inside or outside the body.
Embryonic Development
The fertilized egg (zygote) develops into a mature organism.
Typically has many stages.
Involves cleavage, patterning, differentiation, growth.
Menstrual Cycle
Prepares an egg for fertilization.
Prepares the woman’s body for an embryo.
Human Body Systems
What to know
The parts
What the parts do
How does this system help maintain homeostasis?
How does this system work with others to maintain homeostasis?
If the functions are interrupted, that’s a disease
The body systems work together to maintain
homeostasis
Other important stuff
Diffusion
Stuff moves from where there is more to where there is less ... until a balance is reached.
Surface Area to Volume Ratio
A comparison between the amount of space on the surfaces of an object and the amount of space that object occupies
On the outside(make it as small as
possible)
On the inside (make it as big as possible)
EnzymesEnzymes are proteins that make chemical reactions go faster.
Enzymes are specific to one chemical reaction.
Enzymes are not used up by the reactions in which they participate.
Enzymes fit with the molecules they act on like a lock and key.
Anything that changes the shape of an enzyme (like heat) changes what it does.
Enzymes
Feedback Mechanisms
This is an important way that regulation happens in our bodies.
Feedback mechanisms are like thermostats -- they manage an area of homeostasis around a certain set point.
In order to work, there have to be receptors, set points, and controls.
Feedback Mechanisms
Hormones
Hormones are chemical messengers that tell other parts of the body what to do and when.
9 endocrine glands make over 100 hormones.
Cells have receptors for hormones. If they have receptors for a specific hormone, that hormone can effect the cell. Otherwise, it cannot.
Hormones
Some themesThe more biodiversity, the healthier the ecosystem.
The more genetic variation, the more ability organisms have to adapt and survive.
Every part of a system is connected to every other part (cells/organelles, bodies/body systems, biotic/abiotic, genes/chromosomes).
Humans can have positive or negative impacts on the rest of the world.
The End(for now....)