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Stuff You Need to Know for Next Year. Characteristics of Life. Made of cells Able to reproduce Contains DNA Grows and develops Uses materials and energy Respond to their environment. Levels of Organization . Cells Tissues Organs Organ systems Organisms Population Community

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characteristics of life
Characteristics of Life
  • Made of cells
  • Able to reproduce
  • Contains DNA
  • Grows and develops
  • Uses materials and energy
  • Respond to their environment
levels of organization
Levels of Organization
  • Cells
  • Tissues
  • Organs
  • Organ systems
  • Organisms
  • Population
  • Community
  • Ecosystem
  • Biosphere
getting food
Getting Food
  • Autotrophs are organisms that can capture sunlight or energy to produce their own food. Also called producers.
  • Examples are plants, some algae, and some bacteria.
getting food1
Getting Food
  • Heterotrophs are organisms that rely on other organisms for their energy and food supply. Also called consumers.
types of heterotrophs
Types of Heterotrophs
  • Herbivores obtain energy by eating only plants. Examples: cows, horses
  • Carnivores eat animals. Examples: snakes, owls
  • Omnivores eat both plants and animals. Examples: humans, bears
  • Detritivores feed on plant and animal remains and other dead matter. Example: snails, earthworms
types of heterotrophs1
Types of Heterotrophs
  • Decomposers break down organic materials.
  • Examples are fungi and bacteria.
food chains and webs
Food Chains and Webs
  • A food chain is a series of steps in which organisms transfer energy by eating and being eaten.
  • A food web is a network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem.
ecological pyramids
Ecological Pyramids
  • Ecological pyramids are used to show trophic levels in an ecosystem.
energy pyramid
Energy Pyramid
  • An energy pyramid shows the relative amount of energy available at each trophic level.
  • Organisms use about 10% of this energy for life processes.
  • The rest is lost as heat.
biomass pyramid
Biomass Pyramid
  • Biomass is the total mass of living organisms in a given area or ecosystem.
  • In a biomass pyramid, the greatest amount of biomass is at the base of the pyramid.
pyramid of numbers
Pyramid of Numbers
  • A pyramid of numbers shows the relative number of individual organisms at each trophic level.
cycles in nature
Cycles in Nature
  • The water cycle is the process in which water moves between Earth’s surface and the atmosphere.
  • Water is returned to the atmosphere through evaporation and transpiration (plants).
cycles in nature1
Cycles in Nature
  • Carbon and oxygen are cycled through photosynthesis and respiration.
cycles in nature2
Cycles in Nature
  • The nitrogen cycle is necessary for organisms to make amino acids and proteins.
interactions among organisms
Interactions Among Organisms
  • Competition occurs when organisms attempt to use a resource in the same place at the same time.
  • Predation is an interaction in which one organism (predator) captures and feeds on another organism (prey).
interactions among organisms1
Interactions Among Organisms
  • Symbiosis is a relationship in which two species live closely together.
  • Mutualism is a relationship in which both species benefit. Ex: flower/insect
  • Commensalism is a relationship in which one species benefits and the other is not affected.
interactions among organisms2
Interactions Among Organisms
  • Parasitism occurs when one organism (parasite) lives on or inside another organism (host).
ecological succession
Ecological Succession
  • A series of predictable changes that occurs in a community over time.
two types of succession
Two Types of Succession
  • Primary succession takes place on an area that is originally completely empty of life.
example of primary succession
Example of Primary Succession
  • In an area covered by lava, the first plants will be mosses that grow in cracks in the rock.
  • When they die, they will decompose and begin to form soil which will support grasses.
  • Eventually enough soil is formed to support small trees.
two types of succession1
Two Types of Succession
  • Secondary succession occurs in an area where life once existed but has since been destroyed.
  • For example, a forest that has been destroyed by a wildfire will contain no life. The first plants to grow will be weeds, followed by shrubs, pine trees, and hardwoods.
environmental problems
Environmental Problems
  • Extinction occurs when a species disappears from all or part of its range.
environmental problems1
Environmental Problems
  • Endangeredspecies are species whose population size is declining in a way that places it in danger of extinction.
environmental problems2
Environmental Problems
  • Pollution is any potentially harmful substance added to an ecosystem.
environmental problems3
Environmental Problems
  • Global warming is an increase in Earth’s average temperature caused by human activities adding carbon dioxide and other gases, such as methane, to the atmosphere.
two types of cells
Two Types of Cells
  • Prokaryotes are simple cells that do NOT have a nucleus or organelles. Ex: bacteria
  • Eukaryotes are cells that have a nucleus and organelles. Ex: plant and animal cells
  • An organelle is a structure within the cell with a specialized function.
types of organelles
Types of Organelles
  • 1. nucleus- contains DNA and regulates cell activities
  • 2. mitochondria- supplies the cell with energy through cellular respiration
  • 3. ribosomes- produce proteins
  • 4. Golgiapparatus (body)- processes and packages proteins for export
more types of organelles
More Types of Organelles
  • 5. vacuoles- storage of water, food, wastes, etc.
  • 6. cellmembrane- provides protection and support and determines what enters and leaves the cell.
  • It is semi permeable. Some stuff gets in, and some stuff doesn’t.
cell reproduction
Cell Reproduction
  • Mitosis is the process in which a cell divides into two identical cells.
  • Somatic (body) cells reproduce this way.
phases of mitosis
Phases of Mitosis
  • 1. prophase- DNA condenses to form chromosomes.
phases of mitosis1
Phases of Mitosis
  • 2. metaphase- chromosomes line up in the middle of the cell. Spindle fibers form.
phases of mitosis2
Phases of Mitosis
  • 3. anaphase- Spindle fibers pull chromosomes apart. Half moves into each new cell.
phases of mitosis3
Phases of Mitosis
  • 4. telophase- chromosomes move to opposite sides and nuclear membranes begin to form
  • cytokinesis- cytoplasm pinches in half.
  • Each new cell has an identical set of chromosomes from the parent
  • Interphase- cell grows and develops and makes copies of DNA
  • Cancer occurs when abnormal cells grow and undergo mitosis at an extremely rapid rate.


Why You Look Like You Do

gregor mendel
Gregor Mendel
  • Austrian monk
  • Known as “the Father of Genetics”
  • Performed experiments on pea plants
  • An allele is two different forms of a gene that may be present on a chromosome.
  • A dominant allele will mask (cover up) the other.
  • Two recessive alleles must be present for it to be expressed.
homos and heteros
Homos and Heteros
  • Homozygous means two alleles are the same. Ex: BB, tt
  • Heterozygous means two alleles are different. Ex: Bb, Tt
genotype and phenotype
Genotype and Phenotype
  • Genotype is the genetic makeup of an organism. Ex: tt, Tt, TT
  • Phenotype is the physical expression of a trait (how an organism looks). Ex: short, tall
  • The parent generation is represented by the letter P.
  • The offspring of the parent generation are represented by F1.
  • The offspring of the F1 generation is F2.
  • A monohybrid cross involves two individuals and a single trait.
punnett squares
Punnett Squares
  • If you cross a heterozygous tall plant (Tt) with a short plant (tt), what percent of the offspring will be tall?
discovering dna
Discovering DNA
  • James Watson and Francis Crick discovered the shape of the DNA molecule in 1953.
  • The shape is a double helix (twisted ladder).
  • DNA contains sugar (deoxyribose), phosphates, and nitrogen bases.
  • Two Types of Bases:
  • Purines: guanine and adenine
  • Pyrimidines: thymine and cytosine
  • Adenine pairs with thymine.
  • Cytosine pairs with guanine.
selective breeding
Selective Breeding
  • Selectivebreeding is the breeding of only organisms with desired traits to produced the next generation.
  • For example: horses, cattle, cats, dogs
  • Dolly, a sheep, was the first mammal cloned from a somatic (body) cell.
  • The nucleus from an adult cell was transferred into an unfertilized egg that had its nucleus removed.
  • It was then implanted into another sheep.
  • A karyotype is an organized profile of a person’s chromosomes.
  • Chromosomes are arranged by size from largest to smallest.
  • Humans have 46 chromosomes.
  • It can determine the cause of birth defects or abnormalities.

Make a Karyotype

sex chromosomes
Sex Chromosomes
  • The 23rd pair of chromosomes determines a person’s sex.
  • Females have two X chromosomes.
  • Males have one X chromosome and one Y chromosome.