Jay Eldridge
Punctuated Equilibrium
That evolution occurs both gradually and in small punctured events
Periods of stasis = slow change
Punctuated events = rapid change
Layers closer to water level are more similar ancestors to those further down.
Geographic separation isolates groups creating smaller populations a rapid evolution while larger populations have a slower evolution
Thomas Malthus
He had baby theories, nothing big
Darwin used malthus’ ideas to develop his own theories
Malthus’ said that the human population would grow exponentially but since food grows linearly it would result in lack of food causing death of the human race.
Carrying capacity: Max population that can be sustained by the environment
Understand that there may be a dramatic event that changes the carrying environment.
The ones who survived would carry one those traits to their kids
Jean-bapiste Lamark
Inheritance of acquired traits
Species increase in complexity over time until they reach a level of perfection
Organisms become increasingly better adapted to their environments
Any traits learnt in it’s lifetime could be passed
He believed if a giraffe stretched it’s neck to get food it’s babies would just have longer necks
George Cuvier
Theory of Catastrophism
Developed paleontology - the study of ancient life through fossils.
The theory states that natural events likes floods and volcanic eruptions killed species living in the region which allowed other species to repopulate the area allowing change
Oldest fossils are on the deepest layer “cambrian layer”
A NEW CATASTROPHE (catastrophism) HAPPENED WHENEVER A NEW LAYER OF FOSSILS WERE CREATED
Limitations to the theory
Doesn’t take into part of the slow changes that may occur
Charles Lyell
Principles of Uniformitarianism
Created a theory that states “geological processes operate at the same rate today as they have in the past
- slow subtle change that happens over a long period of time
Limitations to the theory
Doesn’t take into account natural disasters.
Variations:
variations are the structural functional or physiological differences between individuals.
Result of random, heritable mutations in DNA that happens and grows over generations
Heratible:
Transmissible from parent to offspring.
Camouflage
Allows organisms to hide the surroundings to avoid predators
Adaptations:
The result of a gradual accumulative change. Physical and or Physiological
Selective advantage:
a genetic advantage that improves an organism’s chances of survival in terms of both survival in a changing environment and reproduction.
Mimicry:
Structural adaptation that tricks predators into thinking that a harmless species may actually be harmful.
Evolution
Evidence from fossil records. When an organism dies it may form a fossil. A fossil will be the remains or impression of a prehistoric organism cast in rock.
Anatomy
Homologous structures: Are those that have similar structural elements are origins but may have different functions. Flying, running, swimming
Vestigial structures: structures that mammals have but only because a common ancestor had them.
Biogeography
Organisms that live closely together are more similar than organisms that live far away but in similar habitats
Embryology
The study of the early pre-birth stages of an organism’s development.
This has been used to determine relationships between different organisms
All vertebrates have similar stages of early embryo development because all vertebrates haven a common ancestor
DNA
DNA: The blueprint for organism and scientists have been able to determine how closely related two organisms are by comparing how similar their dna is
We know that organisms pass on DNA to their offspring
If two different organisms have similar patterns in their DNA then they must have inherited that DNA from common ancestors
Divergent
Where two species become increasingly different through speciation
Result of selective pressures or genetic drift
When closely related species diversify because of new habitats.
Adaptive radiation
Divergent radiation does not; only have two paths, the species gives life to 3 or more species. The ones who aren’t fit for the environment that will result in path extinction
Convergent
Two different parent species will come together and make them similar in phenotype in response to a similar selective pressure
They begin to share similar appearances because of a shared environment or other selection pressure
Coevolution
Two different species evolving together at the same time
Probably live in the same ecological niche
predator/prey or parasite/host
Competitive or mutualistic species
EX. Acacia plant and ants,
Abiotic and biotic features play a part in the form of evolution
Overproduction
Each species produces more offspring than survive
More individuals are born than can be sustained by their environment, which creates a struggle for existence
Variation
Each individual has a unique combination of inherited traits.
More variation in a species meant a higher chance of survival
Competition
Individuals will always compete for limited resources
Survival of the fittest: how fast and how long can they survive and reproduce for.
Selection
The individuals with the best traits and adaptations will survive and then haven the chance to pass on the trait to the next generation.
Methods of Stabalization
Stabilizing selection
Environment is selecting average phenotypes
Selects against extreme phenotypes
Results in decrease of populations in genetic variance
Example: robins lay 4 eggs, example of overpopulation allowing them to have a higher chance of creating offspring
Directional Selection
Population is shifting in one direction
The environment is selecting for one extreme phenotype and against the other phenotypes
Disruptive selection
When the environment is selecting two extreme phenotypes that each have specific advantages
Selected against the average phenotype EX> lobsters Large lobsters force their way in to mate, small lobsters sneak into famela areas to mate.
Pre
Behavioral isolation
Don’t exchange alleles because they do respond to the same mating rituals
temporal isolation
Species that don’t reproduce because they never meet, thier offspring hatch at different times their breeding seasons are in different time etc
Geographic isolation
Tigers and cheetahs
Ones in Asia and the other is in Africa so they have no chance of mating,
Mechanical isolation
Specific form to reproduce the organism. Parts need to fit so they can mate. They are anatomically incompatible
Class name
Two populations exchange sperm and egg but rarely fuse to form a zygote
Even though population have exchanged cells they can’t fuse into a zygote
Post
Hybrid sterility
Even though the hybrid is healthy and vigorous it is not able to reproduce
Hybrid Breakdown
Even if the first generation hybrids are fertile but when these hybrid mate offspring of the next generation will not survive
Hybrid inviability
even though the zygote is created, it fails to develop to maturity due to genetic incompatibility
eg. Hybrid embryos between sheep and goats die in early development before birth.
Natural selection describes the process of change in the characteristics of a population of organisms over many generations.
Fit is used to define offspring of organisms that can survive and reproduce in the environment which they live
Selective pressure
4 types
Temperature change
Light level change
Change in predators
Change in competition
Artificial selection
is a selective pressure exerted by humans on populations in order to improve or modify particular traits.
Form of BIOtech because it uses organisms to produce useful products.
Heavy Bombardment
Catastrophic beginning with lots of collisions (ie. Mars sized object hit the Earth to form our Moon)
No oceans
Atmosphere filled with carbon dioxide and hydrogen sulfide
Earth was frequently hit by asteroids and meteors
This period of time was thought to aid in the formation of amino acids
Possible that human life originated underground. This is because we wouldn;t have survived with we stayed above the ground}} due to the unless impact of meteors and other celestial objects
First Life Forms
Halophiles –
can live in environments that are very salty i.e. dead sea and pink sea salt formed from bacteria
Acidophiles –
can live in acidic environments i.e. snottites and phlegm balls
Methanogens –
can live in methane rich environments i.e. the bacteria found in the South African mines
Elements key to life on Earth are present
Carbon,oxygen hydrogen nitrogen and
These bacteria are continuously producing oxygen on the planet; creating an ozone layer, giving life to higher life forms so that they could survive.
After multicellular life was formed first there were Fish, then, INsects reptiles, dinosaurs mammals and now so far humans.
Froggy Ironed Red's Dad's Massive Hammock
Variations:
variations are the structural functional or physiological differences between individuals.
Result of random, heritable mutations in DNA that happens and grows over generations
Heratible:
Transmissible from parent to offspring.
Camouflage
Allows organisms to hide the surroundings to avoid predators
Adaptations:
The result of a gradual accumulative change. Physical and or Physiological
Selective advantage:
a genetic advantage that improves an organism’s chances of survival in terms of both survival in a changing environment and reproduction.
Mimicry:
Structural adaptation that tricks predators into thinking that a harmless species may actually be harmful.