Fossils
remains/traces of organisms preserved in rock
the rock cycles processes that form fossils and sedimentary layers
compaction and cementation
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Fossils
remains/traces of organisms preserved in rock
the rock cycles processes that form fossils and sedimentary layers
compaction and cementation
how do fossil imprints occur
they occur when an organism is buried quickly and decomposes slowly
sediment
Small rock fragments such as mud, sand or gravel
relative dating
Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
weathering and erosion
Processes that break down a rock to form sediments.
Lamarck's Theory of Evolution
use and disuse of certain body parts changes them over an organisms' lifetime, and these newly developed physical traits are passed onto their offspring
Example of Lamarck's theory
Giraffe neck length getting longer from generation to generation because they stretched to reach the higher leaves
Darwin's Theory of Evolution
Mutations lead to population variation. The organisms with traits that help their survival live longer and reproduce more, passing on said traits.
Example of Darwin's Theory
A zebra is born with an unnaturally long neck, allowing it to reach more leaves. This means it lives longer and reproduces, passing on the mutation to it's children.
Why lamarck was wrong
The only thing passed down to offspring is the DNA/genes within an organism. These are unrelated to physical traits developed over an organism's lifetime, which cannot be passed down.
population
a group of organisms in the same species living in the same area - they can interact and breed with each other
evolution
is any change in the genetic traits in a population over many generations.
genetic traits
A feature that can be passed down by genes to the next generation
genetic variation
Differences in features or DNA between individuals of the same species
genetic diversity
the amount of genetic variation in a population - helps a species survive when it's environment changes
acquired trait
a trait an individual gains during it's lifetime
genetic trait
a trait passed down generations via genes
Species
A group of organisms that can breed and produce fertile offspring.
speciation
the process of one species evolving into two or more over time
biogeography
study of the geographical distribution of living things
endemic species
species that are native to and found only within a limited area
What is a pentadactyl limb?
A limb with five digits.
In which organisms are pentadactyl limbs found?
In every four-limbed vertebrate.
What does the presence of pentadactyl limbs suggest about vertebrate species?
All species with pentadactyl limbs derived from a common ancestor.
Example of the pentadactyl limb
human hands and gorilla hands have almost the exact same bone structure, but gorilla hands are much larger and stronger due to how they place their body weight on their hands.
Homologous structures
Features in different species that are similar because of common ancestry.
example of homologous structures
pentadactyl limbs (btw this is evidence for evolution)
analogous structures
Similar features in different organisms developed due to them being exposed to the same selection pressures, not due to having a common ancestor
example of analogous structures
fins on sharks and dolphins
vestigial structures
features that lost their purpose over the evolutionary process, becoming redundant/unnecessary, like the appendix
comparative embryology
the study of the similarities and differences in the embryos of different species
biochemical evidence
analysis of DNA or amino acid sequence between organisms to determine if they have common origins
natural selection
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
abiotic
Non-living
biotic
living
adaotation
a physical/behavioural characteristic that helps an organism survive in its environment
who is the theory of natural selection credited to?
Charles Darwin and Alfred Russel Wallace
What are the four requirements of natural selection
Variation, Heritability, Superfecundity, and Non-random Mortality
Heritability
each individual tends to pass its traits onto its offspring
Superfecundity
More young are produced than can possibly survive
Non-random Mortality
survivors have a reason for surviving over their dead counterparts
artificial selection
Breeding organisms with specific traits in order to produce offspring with identical traits.
artificial selection example
dog breeding
structure of a nucleotide
phosphate, sugar, base
the four nucleotides
adenine, thymine, cytosine, guanine
nucleotide complementary pairs
A-T, G-C
DNA
deoxyribonucleic acid - a molecule responsible for storing genetic information in cells
RNA
ribonucleic acid - one nucleotide chain (DNA is made of two)
DNA polymerase
enzyme that makes bonds between nucleotides, forming an identical strand of DNA during replication
DNA helicase
enzyme that 'unzips' the double helix during replication
DNA replication
Process of copying DNA before cell division.
allels
alternative forms of a gene that arise by mutation
phenotype
the observable characteristics of an organism
parsec
the distance at which an object has a parallax angle of one arcsecond
arcsecond
a single second (of degrees, minutes and _____)
what is the process of speciation
individuals from the same species become isolated from one another - forming two separate populations
the genetic characteristics of the two populations change independently of each other - which is reproductive isolation
the two populations now have different selection pressures and mutations, evolving differently until they can no longer breed to produce fertile offspring