Cards Flashcards
Adaption
Physical trait that leads to organism’s increase in survival and reproduction
Fitness
An organism’s ability to reproduce
Theory of Evolution
Charles Darwin’s’ Theory: One way living things evolve
EVERY SPECIES OVERPOPULATES
Overpopulations- more babies than can handle
VARIATION
Lots of variation because we have so many babies
SELECTION
Some individuals are going to survive longer and produce more than others do.
ADAPTATION
Traits become more common in a population
Natural Selection
“Nature selects” animals that are most likely to survive and reproduce
Increase of offspring with that adaptation
Examples of Natural Selection
Peppered Moths and Dandelions (for more info see page 1 on bio test notes)
Artificial Selection
Able to choose traits
Breeding by humans
Effect of Selection on Phenotype and Genotype
If the variation in the population is due to environmental influences alone, any advantage won’t be passed on to the next generation. So natural selection acts on phenotype, but it is the connection to genotype that makes it the mechanism of evolution.
Phenotypes are a combination of genes and environmental influences
Artificial Breeding
Man bread fox and dog together
Chose the tamest of a fox and a dog and bred them together to create a hybrid
Theory
A well supported explanation that unifies a broad range of observations
Theories Explain
Based on loads of experiment
Evidence of Evolution
We all start off the same Evolution explains biodiversity DNA, genetic code, protein Fossil Record, Anatomy: Homologous structures Analogous Structures Vestigial Structures, Embryology, Biochemistry
Fossils
Impression of an ancient organism preserved in rock
The higher up in the rock the younger
The deeper in the rock the older
How do fossils provide evidence for evolution?
Fossils show fewer and simpler species as you go back
Transitional Species Exist
E.g. Horse descendants increase in size and change from toes to hoof
Extinction and formation of new species
Biochemistry
Species that have a common ancestor have similar sequences of amino acids in their proteins or DNA sequences
The more similarities, the closer related the organisms are thought to be
E.g. Human and gorilla hemoglobin differ by one amino acid
Gorillas have 48 chromosomes
Humans have 46 chromosomes
Homologous Structures
Similar features in a common ancestor, but now have different functions and/or external structures
E.g. front limbs of vertebrates
Don’t look similar, but they have the same bone pieces
Analogous Structures
Features that serve identical functions and look somewhat alike but do not share a common ancestor
Mammals with wings have wings, but they aren’t all from the same ancestor
Vestigial Structures
Features that seems no useful function and are usually reduced in size
Structure was useful in an ancestor, but not useful to the current organism
E.g. humans and tail bones
Embryology
Early stages of vertebrate development are similar in different species
Different Evolutionary Pressures
Select different traits Different places Adaptations Depends on environments Sun shines most directly at equator Strong UV rays Can damage or cause cancer Higher and lower Latitudes Higher - less direct sunshine Paler skin Adaptation -Absorb UV rays well Makes vitamin D Light shines most directly at the equator Darker skin is more common in lower latitudes Lactose tolerance Lactose intolerance used to be almost universal Ability to drink milk provided an evolutionary advantage Recent evolution
Alleles can be maintained in a population if they are lethal
Traits do not appear until the individual reproduces E.g. Huntington Disease Don’t develop disease until older Already had children by time they learn of their disease E.g. Cancer Has to be recessive Can “hide” in heterozygous individuals E.g. sickle cell anemia Through natural selection Advantage at equator Heterozygous: gives little advantage against malaria Malaria cannot kill sickle shaped cells
Species
Members of a population that can mate and produce viable offspring
Speciation
wo populations of same species are separated and can’t interbreed
Species are isolated from one another
Species evolve as time passes
Species change so much they can no longer breed
Species are distinct species
When one species branches into two distinct species
Separation: through isolation (causes speciation)
Geographic Isolation
E.g. Kaibab squirrel and Abert’s squirrel
Got seperated and they no longer interbreed
Behaviour Isolation
Occurs when population are capable of interbreeding but have different behaviors that prevent this
E.g. Different Courtship Rituals
Different courtship dances, displays, and/or songs
Patterns of Evolution (causes of evolution)
Natural Selection, Migration, Mutation, Genetic Drift
Migration
Causes an animal to move from one place to another
Mutation
Errors in DNA
Lead to different variations
The stuff that evolution works on
Genetic Drift
NOT natural selection
“Random” Change in surviving and reproducing
Things just survive, but not because they’re more fit
Not because they have a better chance of survival
E.g. Stepping on Bugs
Step on mainly Green Bugs instead of Brown Bugs. Not intentional.
Most common in small populations
Genes drift by random chance
E.g. Elephant Seal
In the 1800s were hunted down
Had a small population
Set up protective law to not make them go extinct
Only current animal’s’ genes passed on to next generations
Trends in Evolution
Coevolution, Convergent, Extinction, Gradualism, Punctuated Evolution, Adaptive Radiation
Coevolution
A change of two or more organisms in close association with each other
E.g. insect pollinators coevolved with plants they pollinate
Hummingbirds and tube shaped flower
Convergent
Organisms appear similar but are not closely related
Happens when the environment selects similar traits
E.g. Sharks and Dolphins
E.g. Birds and Butterflies
Extinction
99.9% of all species are extinct
5 Cataclysmic Events
Most population perished in one of the 5
Possibly in 6th mass extinction right now
Gradualism
Gradual change over time
Slow evolution
Punctuated Evolution
Rapid evolution
Caused by major environmental changes
After disasters
Adaptive Radiation
A species evolves into a wide variety of highly specialized species
E.g. Finches
Early Earth
No life Bombardment by meteors HOT temperatures Not blue atmosphere CO2 NH3 (ammonia) CH4 (methane) H2O (g) Only a little of O2
Formation of Life
Happened in the water 1) Miller - Urey Experiment Mixed Chemicals: chemicals that were around during early earth, heat, and light (lightning) Made amino acids and nucleic acids Earth chemicals + lightning spark + warm early Earth (heat) --> simple organic compounds 2) Phospholipid bilayers spontaneously form Membrane spheres trapped chemicals First Fossils 3) ~3.6 BYA first life fossils Prokaryotes 4) ~3.4 BYA fossils: stromatolites Cyanobacteria
Basic Chemicals of Life
Gases given an electric shock formed building blocks of life
Amino acids, Fatty acids, Hydrocarbons
Places Organic Compounds Are From
Hydrothermal vents
Aboard meteorites
The First Organic Compounds
Fatty acids (lipids) for membrane Enzymes (to do all the work/catalyze reactions for cell) Genetic material (to transmit the information from parent to offspring) Possibly started as RNA
