Transcript Life Science Notes

Grade 7
Life Science
Chapter 1
Exploring Life
Oparin
Characteristics of Living Things
1. Made of Cells (organization)
2. Reproduce
3. Grow & Develop
4. Adaptation
– (stimulus, response, homeostasis)
5. Need food & water (energy), produce waste
Where does life come from?
Spontaneous Generation
Biogenesis
Old thought that
“life comes from nonliving things”
“Life comes from life”
Francesco Redi- first controlled experiment
(change 1 thing) that showed: maggots come
from flies, not rotting meat
Lazzaro Spallanzani- conducted a similar
experiment with broth
Louis Pasteur- showed conclusively that living
things cannot come from nonliving things
If living things can only come from
other living things,
how did life on earth begin?
• Oparin’s Hypothesis: earth’s
early atmosphere was made of
gases and water vapor that is
different from today’s
atmosphere
– Gases formed chemical
compounds & fell into the hot
seas, producing more complex
compounds
– This environment was suitable
for life to begin
VIRUSES
• Virus- piece of hereditary material covered by
protein that infects & reproduces ONLY inside
a living cell
– The living cell is called a host cell
VACCINES
Vaccine- made from damaged virus particles that can’t
cause disease anymore
Edward Jenner (1796)
- Developed the first vaccine for smallpox
Latent vs. Active Viruses
• Latent- appear to “hide” inside host cell for a
certain period of time, until there is a stimulus
– Herpes, mononucleosis, HIV, invading flu, cancer
• Active- exhibiting symptoms for the disease
– AIDS, flu with symptoms
Viral Diseases
Disease
Affected Body Part
Vaccine
AIDS
Immune system
no
Chicken Pox
Skin
yes
Common Cold
Respiratory System
no
Influenza (flu)
Respiratory System
yes
HPV
Cervix (female)
yes
Herpes
Skin
no
Pneumonia
Respiratory System
yes
Smallpox
Skin
yes
HIV/AIDS
HIV = human immunodeficiency virus
AIDS = acquired immune deficiency syndrome
HIV is the virus that causes the disease AIDS.
HIV is spread through:
sexual contact, sharing needles with an infected
person, blood & body fluids, infected mother to
unborn child
Microscopes
• Simple (1 lens)
– Anton van Leeuwenhoek
• Complex (2 lenses)
– Zacharias Janssen
Compound Light Microscope
The Cell Theory
• All organisms are made of 1 or more cells
• Cells are the basic unit of structure and
function in all organisms
• All cells come from cells that already exist
Discovering Cells
• Robert Hooke-discovered cells by looking at
cork under a microscope. (1665)
• You see this
Hooke drew this
Prokaryotic vs. Eukaryotic Cells
Prokaryotic (No)
Eukaryotic (You = true)
No Membrane Bound Nucleus
Has a true membrane bound nucleus
Bacterial Cells
Animal and Plant Cells
Simple one-celled organisms
Complex (one to multi-celled)
The Animal Cell
Organelle
Function
Nucleus
Brains/CEO of the cell
Cell Membrane
Outer Boundary, materials in and out
Cytoplasm
Gel-like material where organelles are
Mitochondria
Mighty Mitochondria, powerhouse
Golgi Body
Packages and Moves Proteins
Ribosomes
Make Proteins
Endoplasmic Reticulum
Super highway, moves materials around
cell
Lysosomes
Sanitation, digest waste
Vacuole
Stores water and waste
Chromatin
Genetic Information
Nuclear Membrane
Outer covering of Nucleus
Diagram of Animal Cell
Plant Cell
Organelle
Function
Nucleus
CEO, brains of the cell
Cell Membrane
Allows materials in and out of cell
Cell Wall
Extra Protection for the plant, rigid
Vacuole
Stores Waste and Water, very large
Chloroplast
Makes Energy for the cell, photosynthesis
Ribosomes
Make Proteins
Endoplasmic Reticulum
Super highway, move materials around
cell
Mitochondria
Mighty Mitochondria, powerhouse
Cytoplasm
Gel-like material for organelles
Chromatin
Genetic information
Nuclear Membrane
Outer boundary for nucleus
Diagram of Plant Cell
How Cells Differ (p.52)
Organizing Cells
Ch. 4-Cell Reproduction
• Mitosis (IPMAT) If Paco Made a Taco
• Stages
• Interphase-Nucleus clearly seen, chromosomes
duplicating
• Prophase-Chromosomes fully visible, nuclear
membrane fades
• Metaphase-Chromosomes line up in the middle
• Anaphase-Chromosomes go to each side of the
cell
• Telophase-2 identical cells are produced
Mitosis Stages
Asexual vs. Sexual Reproduction
Asexual Reproduction
Sexual Reproduction
New organism from one parent
Unique organism produced when sex cells
from two parents combine
Examples: budding, regeneration, fission
Example: All animals
Mitosis
Meiosis (“me”)
46 chromosomes in human skin cell
(diploid)
23 (haploid)chromosomes in egg + 23
chromosomes in sperm = 46 in zygote
DNA-(deoxyribonucleic acid)
• Master copy of an organisms information code
• Your Genetic Blueprint
• Chemicals in DNA are Adenine-Thymine,
Cytosine-Guanine
• Double Helix
• Scientists Watson and Crick created the first
model
RNA-ribonucleic acid
• Code for making proteins
• Single Strand
• Chemicals are Adenine-Uracil, CytosineGuanine
Genes, Gene Mutations, Human
Genome
• Genes-a section of DNA on a chromosome
that directs a specific protein
• Genetic Mutation-a miscoded gene caused by
aging, radiation, pollution, etc.
• Human Genome Project-map of our genes
25000 +
• Gene Therapy-using a virus to
correct a miscoded gene
Chapters 2 & 4 Websites
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www.biology4kids.com
www.cellsalive.com
http://learn.genetics.utah.edu
http://www.ibiblio.org/virtualcell/
http://vcell.ndsu.nodak.edu/animations/
Ch. 5- Heredity and Genetics
• Gregor Mendel-Father of Genetics, studied pea
plants to see what traits showed up most often in
reproduction
• Genetics-study of how traits are inherited with
alleles
• Heredity-passing of traits from parents to
offspring
• Allele-different forms a gene may have for a trait
More to Know
• Dominant Trait-trait that shows up most often
in an offspring (50%), only 1 Parent
• Recessive Trait-trait that is usually covered up
by the dominant trait, shows up (25%), 2
Parents must have
Genotype vs. Phenotype
• Genotype-genetic make-up of an organism
• Phenotype-physical trait expressed in an
organism
Punnett Square
• Heterozygous-2 alleles for a trait that are
different
• Homozygous-2 alleles that are the same
• Punnett Square-a handy tool to help us
predict how often traits will show up in an
offspring
Chapters 2, 4, and 5 Websites
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www.biology4kids.com
www.cellsalive.com
http://learn.genetics.utah.edu
http://www.ibiblio.org/virtualcell/
http://vcell.ndsu.nodak.edu/animations/
Chapter 6-Evolution
Vocabulary
• Species-group of organisms whose members
successfully reproduce among themselves
• Evolution-change in the hereditary features of a
species over time
• Natural Selection-organisms with traits best
suited to their environment are more likely to
survive, “Survival of the Fittest”
• Variation-appearance of an inherited trait that
makes an individual different from other
members of the same species
More Vocab.
• Gradualism-the model that describes evolution as
a slow change of one species to another new
species
• Punctuated Equilibrium-rapid evolution of species
can come about by the mutation of just a few
genes
• Fossils-are any remains of life from an earlier
time, ex. Imprint of a leaf, fossilized rock, frozen
in ice, casts made of minerals filled in the hollows
of a part of an organism
Charles Darwin
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Darwin traveled the world studying plants, animals and fossils.
His most famous exploration was of The Galapagos Islands
He collected evidence of variations among species
Through observations/experiments he concluded that
individuals with traits most favorable for a specific
environment survived and passed traits on to their offspring
Natural Selection Factors
• Organisms produce more offspring than can
survive
• Variations are found among individuals of a
species
• Some variations enable members of a population
to survive and reproduce better than others
• Over time, offspring of individuals with helpful
variations make up more and more of a
population
Extinction and Evolution
• Extinction is the dying out of a species due to
changes in the environment (ex. Dodo bird,
Tasmanian Wolf, Saber tooth Tiger)
• Endangered Species have so few individuals
left that they are in danger of becoming
extinct (ex. Polar Bears, Tigers, North
American Alligator)
Evolution Timeline
Chapter 6 Websites
• www.biology4kids.com
• http://science.discovery.com/interactives/liter
acy/darwin/darwin.html
Primate Evolution
Chapter 7
Classification
• Taxonomy- the science of classifying and naming
organisms
• Binomial Nomenclature- two-word naming system
Genus
Acinonyx
Species
A. jubatus
Taxonomic Categories
“Trick”
Taxonomy
King
Kingdom
Philip
Phylum
Came
Class
Over
Order
For
Family
Great
Genus
spaghetti
species
Genus- group of different organisms that have similar characteristics
Species- smallest, most precise classification
organisms belonging to the same species can mate with each other to produce
fertile offspring
Fill-in the classification of Humans
The 6 Kingdoms of Life!
Achaea
Type of
cells
Cell #
Bacteria
Protist
prokaryotic
prokaryotic
eukaryotic
eukaryotic
eukaryotic
eukaryotic
Single
Single
Single or
many
Many
Many
many
Most
Some
Don’t
Move
Don’t Move Move
Food
producers
Movement Some
Fungi
Plant
Nutrition
Some make
food, Most
absorb food
from other
sources
Some make
food, others
obtain it
Some make
food, others
obtain it
Obtain
food from
organisms
on which
they live
Examples
Methanogen
Halophile
Thermophile
Cyanobacteria
E Coli
Euglena
Paramecium
Amoeba
Slime mold
Mushroom Moss
Yeast
Trees
Penicillin
Flowers
Bread
Mold
Animal
Food
consumers
Sponges
Cnidarians
Worms
Fish
Amphibian
Chapter 7 Websites
• www.sciencenewsforkids.com
• http://www.freedict.com/onldict/lat.html
• www.biology4kids.com