Biology Lecture Final Flashcards
(90 cards)
Cell theory
All organisms are made of cells and all cells come from pre-existing cells. This came about in the mid 1800s
Theory
An explanation for a very general class phenomena or observations
Evolution
The process by which species have changed and diversified since life first arose. Explains unity, all living things share the same characteristics and the diversity if life.
Natural selection occurs when two conditions are met-
- Individuals within a population vary in characteristics that are heritable ( traits that can be passed on to offspring). A population is defined as a group of individuals of the same species.
- Certain versions of these heritable traits help individuals survive better or reproduce more than other versions
Artificial selection
Changes in populations that occur when humans select certain individuals to reproduce the most offspring
Eukaryotes
Cells have a nucleus. Are multicellular. Animals, fungi and plants
Prokaryotes
Do not have a nucleus. One celled. ex: Bacteria and archaea
Taxonomy
To name and classify organisms
Taxon (taxa, plural)
Any named group
Domain
Three domains of life bacteria, archaea and eukarya
Phylum (phyla, plural)
A term to refer to major linages within in domain.
Taxon- domain- phylum
Scientific name.
- Swedish botanist came established a system for naming species. A two part name made for the organism. First part to the name is called the genus and the second part of the name identifies the organisms species. Ex: homo (genus) sapiens (identifies species)
Null hypothesis
Specifies what we should observe when the hypothesis being tested isn’t correct
Chemical evolution
Leading explanation for the origin of life.
Inputs of energy on early earth led to the formation of increasingly complex carbon containing substances, culminating in a compound that could make a copy of itself or self replicate.
What are the four molecules that make up 96 percent of all matter found in organisms.
Hydrogen, carbon, nitrogen and oxygen
Atomic number
The number of protons of an element
Mass number
The sum of protons and neutrons
Isotopes
Forms of an the same element with different numbers of neutrons
Covalent bond
Results when two atoms share electrons in order to have a completed two electrons.
Molecules
A group of atoms together. When it contains atoms of more than one element it is called a compound. There are two types if chemical bonds: ionic and covalent
Nonpolar covalent bond
Because carbon and hydrogen have approximately equal electronegativity the electrons in a C-H bond are shared equally
Polar covalent bond
Atoms that tend to be mor electronegative tend to hold shared electrons more tightly. Meaning atoms on both sides of the bind are partially charged.
Ionic bonds
Forms when two atoms are held together by the attraction between opposite charges. This makes ions; charged atoms.
Cation
Positively charged ion. Has electrons taken away from it