Ch 13 evolution Evidence of change Flashcards
who was Charles Darwin
- Charles Darwin (1809-1892) contributed more to our understanding of evolution than any other scientist
- During his 5 year long voyage on the HMS Beagle Darwin spent many hours collecting, cataloging and studying organisms
- The vast diversity of life he saw lead him go question the origin of species
what are adaptations
Darwin thought that certain inherited traits would be better for the organisms survival
these would be called adaptations
what are structural adaptations
structural adaptations were physical traits
what are behavioural adaptations
Behavioural adaptations affect how the organisms acts
what are biochemical adaptations
Biochemical adaptations allow the organisms to do things like produce venom, and maintain homeostasis
what is fitness in an evolutionary sense
- Darwin thought the traits that allowed the organism to survive and reproduce would give the organism a fitness towards it’s environment
- creatures more fit to their environment were more likely to reproduce and pass on their traits
what is Darwins theory of common descent and speciation
- Darwin theorized that as species changed over time they become more and more distinct, and can form new species
- he though that all organism had evolved from others, and by tracing back evolution everything was related to a single universal common ancestor
which scientists helped prove the magnitude of geological time
- For the process of Evolution to produce the variety we see today an immense range of time is required to exist in earths past
- James Hutton observed the process that shaped the earth occurred very slowly and thought that therefor the earth must be very old to posses mountain, valleys, and other features
- Charles Lyell agreed and further evidence led them to argue the age of the earth and geological change
what are fossils
- Fossils are preserved remains of dead organisms found in sedimentary rock
- they form rarely so the fossil record is necessarily incomplete, and estimated 0.01% of organism are seen in the fossil record
- Fossils show change in organism and even climate
what process leads to fossil formation and discovery
- Dead Organisms can eventually get buried in sediment, the sediment turns to rock, and eventually the organic material can be replaced with mineral compounds, petrifying it, and in even rarer cases soft material are preserved
- Fossils can eventually reach the surface and they might be discovered by scientists, who might then reconstruct the organism, or otherwise use the fossil to learn about the long dead organism
what are palaeontologists
Palaeontologists are scientists that study the fossil record to see how organisms and environments have changed as well as to make a history of life.
what is relative dating
relative dating compares layers of rock to set the age of some deposits relative to others, but this is not process of give us the actual age.
what is radioactive dating
- Radioactive elements breakdown into new ones at a steady rate, each isotope has a half-life (the time for 1/2 of any sample of the atoms to decay) After 1HL you have 1/2, after 2HF you have 1/4, after 3HF you have 1/8, etc
- Knowing the half life of a particular isotope, using measurements we can calculate how many half-lines have passed and therefor the age of the sample
what are the four eons of earth’s history
Eon 1: The Hadean: 4.6-4 bya
Eon 2: The Archean: 4-2.5 bya
Eon 3: The Proterozoic: 2.5 bya-541 mya
Eon 4: The Phanerozoic: 541 mya-present
what are the three eras of the Phanerozoic
Era 1: The Palaeozoic: 541-252 mya
Era 2: The Mesozoic: 252-66 mya
Era 3: the Cenozoic: 66 mya - Present
