Chapter 1 Flashcards
What is DNA made up of?
-made up of nucleotides joined together
Functions of DNA
- carrier of genetic information
- controls cell activities and gives you your traits
What are the 3 parts to nucleotides?
- Sugar - deoxyribose
- Phosphate group
- Nitrogen base (4 of these)
What are the four nitrogen bases? Answer in the pairs they are found in
Adenine (A) paired with Thymine (T)
Guanine (G) paired with Cytosine (C)
Define chromosome
Long strand of DNA which has many genes on it
How many chromosomes do humans have?
46
Define gene
Small strand of DNA and has codes for a particular protein or trait
What is the purpose for DNA replication and when and how does it occur?
It occurs during mitosis so there is a copy of the DNA for the new cell. Steps: 2 strands of DNA separate for replication
Complementary base pairing occurs to form new DNA
Bonds replaced
What are the uses of DNA?
- research for medicines
- gene therapy
- forensics
- paternity test
Define evolution
Theory that groups of organisms change over time to look different from their ancestors
What oxygenated the earth?
Bacteria and algae
What does sexual reproduction do?
Leads to variation
Half of the genetic information from each parent
Differences due to genes found on the chromosomes
Increases organisms chances for survival
Mutations can be passed on by sexual reproduction which drives evolution
Define mutation
A mutation is a permanent change in the DNA of cells
What is the main source of new alleles?
Mutations
If organisms of a species are too similar then they:
- Won’t be able to adapt to changes that occur
2. Could get wiped out by a virus
Define species
A species is an organism that can interbreed and produce fertile offspring and the individual all look similar
Name evidence for evolution
- fossils
- fossil record
- tarpits
- Amber
- flash frozen
- comparative anatomy
- embryology
- DNA
What is a fossil?
Fossils are preserved remains of ancient organisms. They formed when plant or animal matter is changed to stone or the “imprint” is solidified
What is a fossil record?
- collection of fossils that show change within a species over time (history of organisms)
- has gaps in it so it is said to be incomplete (transition fossils are missing)
What is a tarpit?
- once was thick mud where animals had been trapped and died
- teeth and bones have been found in tarpits
What is amber?
-hardened gum or sap of a tree where insects usually will get trapped and preserved
Define flash frozen
Organism quickly frozen in ice
What is comparative anatomy?
What similar structures did the animals have, then lose or gain, compared to animals of today.
Examples are skeletal, nervous, and circulatory systems
What is embryology?
In vertebrates, the early stages of development look very similar with tails and gill slits
- therefore, similar ancestors
- embryology traces evolutionary pathway
What has the same structure for every living thing on earth?
DNA
Which sedimentary rock layers are the oldest?
The deepest layer.
What is the Burgess Shale and where is it located?
The Burgess Shale is the resting place to a vast amount of 530 million year old sea creatures and is located in the Rocky Mountains.
What are two examples of organisms found in the Burgess Shale?
Opabinia and hallucigenia
How many mass extinctions have there been?
5
Why is the Burgess Shale remarkable?
Life forms of half-billion years old remain preserved and almost intact
What is radioactive dating?
Radioactive dating is measuring the decay of radioactive isotopes. Scientists use this method to calculate the ages of rocks and fossils
What radioactive isotope is used to date old fossils over 50,000 years?
Potassium and uranium
What radioactive isotope is used to date young fossils less than 50,000 years?
Radioactive carbon dating