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204 terms

Science Exam Vocab

Vocab for March exam for science you're welcome everybody
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evolution
the process by which species gradually change over time.
Charles Darwin
an English naturalis. He studied the plants and animals of South America and the Pacific islands, and in his book On the Origin of Species by Means of Natural Selection (1859) set forth his theory of evolution.
HMS Beagle
the ship Darwin sailed on a 5 year trip around the world. He studied fossils (preserved remains of organisms) in Argentina and Brazil and zoology (types of animals) in the Galapagos Islands.
scientific theory
a statement that has been backed up by experimentation. It is not a fact. It is only as strong as its evidence!
diversity (how Darwin's trip changed his thinking)
an infinite number of animals and plants, each with adaptations suited to their environment.
fossils (how Darwin's trip changed his thinking)
older bones were similar but different to newer bones.
adaptations (how Darwin's trip changed his thinking)
animals from the same species appeared to develop traits to survive in new environments.
On the Origin of Species
Darwin's most famous book which contained observations from his trip.
theory of evolution
species gradually change over time to adapt better to their environment.
theory of natural selection
organisms better adapted to their environment will survive and reproduce-"Survival of the Fittest".
what causes natural selection to happen?
overproduction, variation, and competition. Changes to environment can affect an organisms ability to survive and can lead to selection.
overproduction
species that produce more offspring survive better.
variation
offspring differ from each other in many ways.
competition
a limited supply of food and other resources and presence of predators leads to competition between species.
evidence supporting theory of evolution
fossils, similarities in early development, DNA comparisons
fossil
the preserved remains of an organism
homologous structures
adaptations that organisms inherited from a common ancestor.
analogous structures
adaptations that are similar because of a common environment.
early development: organisms at birth
comparing animal fetuses shows similarities not obvious in adult form.
DNA comparisons
comparing animal DNA and gene makeup shows similarities not obvious in adult form.
branching tree
a diagram that identifies time points where new species are made. Shows how different organisms evolved from each other. Less levels of shared classification = bigger differences in appearance.
when do new species form?
when a group of individuals remains isolated from the rest of its species long enough to evolve different trait.
how do fossils form?
1) Animal dies and is buried under layers of sediments (particles of soil and rock)
2) Sediments harden to become rock and animal is preserved as a fossil
3) Rock erodes and fossil is exposed
types of fossils
petrified, molds/casts, preserved
petrified fossils
minerals soak into bones, turning them into rocks.
molds/casts
bones dissolve, leaving gaps.
preserved fossils
full animal stored in ice or other minerals.
relative dating
Fossils found higher on rock are younger than fossils found lower on rock.
Used to compare fossils.
Does not tell scientists actual age.
radioactive dating
Compare amount of radioactive element in fossil to amount of other elements in which it breaks down
Work backwards from present to calculate age.
radioactive element
unstable elements that decay (break down) into different elements.
half-life
time it takes for half the atoms in a sample to decay.
fossil record
the millions of fossils scientists have collected over time.
geologic time scale
calendar of Earth's History, created using radioactive dating from fossils.
Calendar goes backwards-starts millions of years ago, ends at present time.
unanswered questions about evolution
what causes mass extinctions?
do species evolve by gradualism or punctuated equilbria?
mass extinctions
scientists hypothesize (make an educated guess) that major climate change is responsible.
gradualism
evolution occurs slowly but steadily over time, which is how Darwin thought evolution occurred.
punctuated equilbria
the theory that species evolve by rapid changes separated by long periods of little or no change, which accounts for gaps in the fossil record.
organism
a living thing.
unicellular
made of one cell, such as bacteria.
multi-cellular
made of many cells, such as animals.
characteristics that all living things share
have a cellular organization, contain similar chemicals (water, proteins, carbohydrates, lipids/fats, and DNA), use energy, respond to their surroundings, grow and develop, reproduce.
stimulus
a change in an organism's surroundings that causes the organism to react.
response
a reaction or change in behavior.
growth
organisms use energy to get bigger
development
the process of change that occurs during an organism's life to produce a more complex organism.
reproduction
produce offspring through seeds, eggs, or clones.
theory of spontaneous generation
the mistaken idea that living things can arise from non-living things. Scientists found this by observing flies growing from dead meat.
classification
the process of grouping things together based on their similarities.
why do scientists classify?
to make organisms easier to study.
taxonomy
the classification of living things by similar traits.
Carolus Linnaeus
a pioneer of Taxonomy who developed organism naming system that is used today Each organism has 2 names: genus and species. 1st: Genus - Group of organisms that are closely related. 2nd: Species - Distinct feature of the species. Capitalize genus but not species.
taxonomic keys
are used to determine the identity of an organism. They use traits to classify organisms.
levels of classification
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (Didn't Kin
more levels two organisms share = more similar they are.
evolution and classification
species with similar ancestors and similar cell structure are classified more closely together.
domain
1st step on the classification ladder. Based on: cell type, make food/eat food, and number of cells in body.
autotroph
get food from sunlight/other chemicals.
heterotroph
get food from other organisms.
prokaryote
an organism without a nucleus in their cells.
eukaryote
an organism with a nucleus in their cells.
Domain Bacteria
prokaryote, unicellular, autotrophs and heterotrophs.
Domain Archaea
prokaryote, unicellular, autotrophs and heterotrophs.
Difference from bacteria: found in extreme conditions, heat, acid, salty, sewage.
Domain Eukarya
organisms have cells with a nucleus.
Divided into 4 kingdoms, protists, fungi, plants, animals.
Protist Kingdom
eukaryote, unicellular and multi-cellular (algae), autotroph and heterotroph.
Fungi Kingdom
eukaryote, multi-cellular (except for yeast) heterotrophs that digest food outside their body & then absorb it.
Plant Kingdom
eukaryote, multi-cellular autotrophs that absorb sunlight to make glucose.
Animal Kingdom
eukaryote, multi-cellular heterotrophs that capture and eat their food.
bacteria
unicellular prokaryotes.
cilia and flagella
move cell.
shape and size of bacteria
spherical shape, rod shape, and spiral shape.
size ranges from 1/1,000th of a meter to 1/1,000,000th of a meter.
reproduction of bacteria
asexual: binary fission
sexual: conjugation
endospore formation
binary fission
one cell divides to form two identical cells.
genetics
the study of heredity
inheritance
transmission of DNA from parents to offspring
Gregor Mendel
"The Father of Genetics." A priest and a gardener who cross-fertilized purple and white plants. First he found that all 4 of the F₁ generation was purple, then he found that 1 out of 4 of the F₂ was white.
trait
characteristic of an organism that is passed down, such as seed color or stem height.
fertilization
combine the sperm from one organism with the egg of another organism.
purebred
an organism that has the same alleles for a trait.
p generation
parent generation.
f₁ generation
offspring of the p generation.
f₂ generation
offspring of the f₁ generation.
allele
the different forms of a gene. Each organism must have 2 of these from each trait, one from Mom's and Dad's.
dominant allele
an allele whose trait always shows up in the organism when the allele is present. Represented by a capital letter.
recessive allele
an allele that is hidden whenever the dominant allele is present. Represented by a lowercase letter
gene
the factors that control a trait, a segment of DNA on a chromosome that codes for a trait.
heredity
the passing of physical characteristics from parents to offspring.
hybrid
an organism that has two different alleles for trait.
Punnett square
a chart used to predict the results of a genetic cross. Used to predict the outcome of meiosis
probability
the likelihood that something will happen. It is a prediction, not a fact.
genotype
the alleles of an organism.
homozygous
same alleles for a trait, purebred.
heterozygous
different alleles for a trait, hybrid.
phenotype
the physical appearance of an organism.
co-dominance
when two or more alleles have equal dominance, so hybrids show both alleles. Write these alleles as superscripts.
genome
all of the DNA in one cell of an organism.
chromosomes in a human cell
23 pairs-one from mom and one from dad.
chromosome
a structure in the nucleus that contains genetic material.
haploid
50% of DNA.
diploid
100% of DNA.
homologous chromosomes
chromosomes with matching information.
asexual reproduction
produce offspring with identical DNA from 1 organism-use mitosis.
sexual reproduction
produce offspring with DNA from 2 different organisms.
meiosis
the process that occurs in the formation of sex cells (sperm and egg) by which the number of chromosomes is reduced by half.
chromatid
each half of the chromosome.
centromere
holds the 2 chromatids together.
objective of meiosis
make a 4 sex haploid cells from a diploid cell where haploid contains 1 allele of each gene.
purpose of meiosis
to make 4 sex cells to pass on to the next generation.
How do we make babies with shared characteristics from each parent?
need to make cells with half of the DNA from each parent and then merge them into a new cell.
x and y chromatids
determine the gender of an organism.
xx
female.
xy
male.
meiosis 1: start
cell nucleus has 4 chromatids: 2 from mom and 2 from dad.
meiosis 1: prophase
cell makes copy of each chromatid-4 homologous chromosomes; mom and dad chromosomes swap similar genes.
meiosis 1: metaphase
mom and dad chromosomes line up in the center of the cell, and are held together by spindle fibers attached to the centromeres.
meiosis 1: anaphase
nucleus breaks down and chromosomes are pulled apart by spindle fibers-cell divides.
meiosis 1: telophase
cell ends up with two chromosomes each, having one allele of each gene from mom and dad.
meiosis 2
new cells split again to produce 4 new cells, with two chromatids each-1 chromatid from mom and 1 from dad.
what doesn't happen in Meiosis 2?
DNA does not copy.
DNA
deoxyribonucleic acid, contains genetic material in 2 strands.
nucleotide
a segment of DNA that consists of sugar, phosphate, and nitrogenous base.
sugar (deoxyribose)
foundation.
phosphate
connection between nucleotides.
nitrogenous base
code of DNA (adenine, thymine, cytosine, guanine)
adenine goes to thymine; cytosine goes to guanine.
relation between each strand of nucleotide
top strand is the reverse of the bottom strand.
how to copy DNA
top strand "unzips", give DNA to offspring.
mutation
an error of copying DNA. Errors can create new alleles. Can effect trait, phenotype, and chance of getting disease.
mutation
an error of copying DNA. Errors can create new alleles. Can effect trait, phenotype, and chance of getting disease.
RNA
ribonucleic acid, contains uracil instead of thymine in DNA. Assists in protein synthesis by carrying code from DNA to ribosome in cytoplasm.
Friedrich Miescher
In 1869, he discovers a white substance in the nucleus of cells.
Phoebus Levene
In 1920, he finds that DNA contains:
a) DNA Backbone: Deoxyribose Sugar and Phosphates
b)Nitrogen Bases (A, G, C, T)
Rosalind Franklin
In 1952, she takes X-ray photos of DNA and shows it looks like a helix.
James Watson and Francis Crick
In 1953, they use Franklin's data (without permission) to show that DNA looks like a double helix.
Where do organisms get each set of their genes?
From their parents (Mom and Dad).
cells
form the parts of an organism and carry out all of an organism's functions.
structure
what an object is made of and how its parts are put together.
function
the processes that enable it to stay alive and reproduce.
Robert Hooke
In 1660 he used his compound microscope to look at slices of cork. He saw boxes and called them cells because they looked like small rooms.
Anton van Leeuwenhoek
In 1673, he used a simple microscope and saw living things in pond and lake water.
Matthias Schleiden
In 1838, he saw that all plants were made of cells.
Theodor Schwann
In 1838, he saw that all animals were made of cells.
Rudolf Virchow
In 1855, he saw cells dividing to make more cells.
cell theory
1) All living things are made of cells.
2) Cells are the basic units of structure and function of living things.
3) All cells are made from other cells.
1st level of organization-cells
building block of all structures.
2nd level of organization-tissues
a group of cells that perform a specific function.
3rd level of organization-organ
a group of tissues that perform a specific job-heart.
4th level of organization-organ system
a group of organs that work together to perform a specific job.
organelle
a tiny cell structure that carries out a specific function within the cell.
cell membrane
holds organelles in cell
Controls transport in/out of cell-front gate.
nucleus
contains all code for:
Building new organelles.
Turning organelles on/off-control center.
mitochondria
respiration: Break down sugars to provide energy for cell-power source.
ribosomes
produce proteins-machines of cell.
protein synthesis
the process of producing proteins by ribosomes.
endoplasmic reticulum (ER)
transporting objects around the cell-highway.
smooth ER
no ribosomes.
rough ER
covered with ribosomes.
golgi body
package objects for transport inside and outside of cell-post office.
vacuoles
stores supplies: water, salts & sugars-closet.
central vacuole
(only in plant) storage of water, salts & sugars.
supports structure of cell.
lysosomes
releases chemicals that break down dead organelles.
Recycles parts for ribosomes-trash can.
centrioles
used for Mitosis - Cell Replication.
microfilaments
maintain cell structure.
Hold organelles in place.
nucleolus
the structure in the nucleus which produces ribosomes.
cytoplasm
the soupy material between the cell membrane and the nucleus.
microtubles
form the internal structure of the centrioles and helps move organelles.
cell wall
(only in plant) protects and support the cell.
Give structure strength.
chloroplasts
(only in plant) contain pigments called chlorophyll.
Use sunlight to carryout photosynthesis.
chlorophyll
a green pigment in plants that absorbs light energy used to carry out photosynthesis.
brownian motion
what we learned from Robert Brown's work.
Particles are always constantly moving in random directions.
Randomly moving particles that hit each other will move in opposite directions.
diffusion
tendency of particles to move from high concentrations to low concentration-a type of passive transport.
permeable cell membrane
all particles can pass through.
selectively permeable cell membrane
some particles can pass through.
impermeable cell membrane
no particles can pass through.
cell needs
water, oxygen, food, messages.
osmosis
diffusion of molecules through a semipermeable membrane that is driven by the presence of sugars/salts on one side from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal.
water and sugar molecules
water molecules bind to sugar molecules.
Cells contain sugar molecules (used for energy).
Cell membrane is:
Permeable to water.
Impermeable to sugars.
isotonic
equal amounts of sugars/salts in and out of membrane-stays same shape.
hypertonic
more sugars/salts out of cell-water travels out.
hypotonic
more sugars/salts in cell-water travels in.
composition of cell membrane
Made of particles called phospholipids. They have two parts: hydrophobic and hydrophilic.
hydrophobic
part of phospholipid that doesn't like water.
hydrophilic
part of phospholipid that likes water.
organization of phospholipids
phospholipids organize into a double layer to form the cell membrane because of the two parts.
passive transport
movement from high concentration to low concentration without using energy.
Phospholipids move around.
cholesterol
used to prevent membrane from moving.
transport proteins
during active transport, they pick up molecules and carrying them in using energy.
active transport
Cells need particles that are hard to find.
Concentration of particles outside the cell is very low.
Passive transport cannot be used to get particle into cell-needs energy.
Use energy (ATP) to force particles from low concentration to high concentration.
endocytosis
a type of active transport where cells capture particles by engulfing them.
exocytosis
a type of active transport where cells get rid of particles which are packaged by the golgi body by spitting them out.
pores
holes in a membrane.
eukaryotic cell
complex cells that contain a nucleus, organelles and a genetic material with many chromosomes.
mitosis
the process that eukaryotic cells use to make identical copies of themselves.
chromosomes
strands of genetic material.
steps of cell cycle
interphase, mitosis, cytokinesis.
stages of mitosis
prophase, metaphase, anaphase, telophase.
interphase
1st stage of cell cycle. Cell grows in size; makes a copy of DNA in nucleus; makes more organelles; makes centrioles.
centriole
organelle in an animal cell that helps to organize cell division and make microfilaments.
prophase
1st stage of mitosis. Chromosomes form chromatid structure; identical chromatids connect to each other using a centromere
chromatid
one of two identical strands into which a chromosome splits during mitosis.
centromere
area where the chromatids of a chromosome are attached.
metaphase
2nd stage of mitosis. Centrioles move to either side of nucleus; chromosomes line up in center; spindle fibers connect chromosomes to both centrioles.
spindle fiber
connect chromosome to both centrioles and pull chromosomes to either side in metaphase.
anaphase
3rd stage of mitosis. Centromeres split in half-chromotids copy 1 go up, chromatids copy 2 go down.
telophase
4th stage of mitosis. Nuclear membrane forms around 2 groups of chromatids. Chromatids structure go back to chromosome DNA. Cell starts to split into two.
cytokinesis (animal)
Cell splits into two new cells. Each has own organelles and DNA. Membrane pinches together.
cytokinesis (plant)
Cell splits into two new cells. Each has own organelles and DNA. Cell plate forms in center and becomes membrane.