Unit 8: Natural Selection/Adaptations
Charles Darwin What controls mating in the natural environment?
* Malthus' theory of human population growth * Limited resources results in a competition for survival * Only those organisms which survive can reproduce, and thus, pass on their genes. * Nature, itself, acts as the selection pressure determining who will reproduce
The theory of Natural Selection
* Variation exists within a species. These variable traits are passed from one generation to the next. * More organisms are produced in each generation than can survive. *Therefore, organisms compete with one another to survive. * Those organism possessing traits that are best adapted to the environment will survive. * Those organisms which survive will reproduce. The favorable adaptations they possessed which allowed for their survival will be passed on to their offspring. * New generations will have a higher percentage of the favorable alleles/traits
Flower Reproductive Process Fertilization
*Growth of the pollen tube through the style *Sperm travels down the pollen tube into the ovary to combine with the egg inside the ovule *Results of fusion -->egg and sperm: embryo -->ovule: seed coat -->ovary: fruit
Adaptations found in plants
Adaptations in plant are designed to avoid predation
Problems with acquire inheritance
Additional bones Organisms can think like that Acquired inheritance aren't passed from parent to offspring
Flower Reproductive Process Methods of Pollination
Animal Aided (adaptations: bright, nectar, scent, big) Wind Aided (adaptations: tall anther, tons of pollen, tiny flower)
Adaptation
Any change within a species which allows its members to be better suited for survival in a given environment
Charles Darwin How can a trait be changed over time?
Artificial Selection: Darwin noticed that farmers could alter characteristics of their animals by controlled mating. By controlling which organisms mate, farmers controlled which genes were inherited, thus changing the overall frequency distribution for a trait in the population.
Areas of adaptation
Avoid predation Aid in predation (getting food) Tolerating environment
Adaptations found in animals Cryptic Coloration/ Defensive Camouflage
Being able to blend in to environment *camouflage only works if associated with appropriate surrounding/behavior
Adaptations found in plants Nutrient Exclusion
Certain plants exclude from their tissues nutrients which animals need in large quantities
Evolution
Change over time
Macroevolution
Change which results in the advent of new groups of organisms
Microevolution
Change within a population or species resulting in greater adaptiveness to the environment
Hardy Weinburg Equilibrium
Constructed a model that shows no genetic change from 1 generation to the next (no evolution)
Adaptations found in plants Morphological defenses
Design elements of a plant to avoid predation
Flower Carpel (Pistal) Function
Female sex organ of flower
Charles Darwin Specific data that sparked interest in evolution
Fossil record Adaptive Radiation (when they move they adapt) Indigenous Species (Where species live or originate from)
Method of Evolution Lack of Isolation
Gene Flow process of genes moving from one population to another
Acquired inheritance
Giraffe
Method of Evolution Selection Pressure Directional Selection
Individuals that have a more extreme form of a trait have greater fitness than individuals with an average form of the trait
Method of Evolution Selection Pressure Stabilizing Selection
Individuals with the average form of trait have the highest fitness
Industrial Melanism
Industrial melanism refers to the evolution of dark body colours in animal species that live in habitats blackened by industrial soot.
Flower Stamen Function
Male sex organ of flower
Charles Darwin Conclusions
Much variation exist among members of the same species Physical traits and their variations must be heritable Characteristics of species change over time
Requirements for a non-evolving population
No natural selection No mutations No gene flow (immigration or emigration) No sexual selection Infinitely large population
Method of Evolution Non-random Mating
Nonrandom mating affects which alleles will be combined within individuals, but it does not affect overall allele frequencies within a population Sexual Selection *Females tend to choose the males they mate with based on certain traits
Mimicry
Organisms have adapted to resemble another species for their own benefit
Key elements of Lamarcke's theory of evolution
Organisms possess an inherit urge to better themselves Organism can adjust their traits according to desires Organisms can pass on traits they acquire during their lifetime
Adaptations found in animals Chemical Defenses
Production of chemicals/toxins which deter predators Often associated with warning coloration
Jean Baptiste de Lamarcke
Proposed the first theory concerning a mechanism of evolution
Method of Evolution Small Population
Random genetic drift the failure of even a single organism to reproduce can significantly disrupt the allele frequency of the population, as can greater-than-normal reproduction by an individual
Adaptation focus
SURVIVAL
Flower Function
Sexual reproductive organs
Charles Darwin
Spent 5 years as the naturalist on the HMS Beagle collecting data on geology and life
Adaptations found in plants Chemical Defenses
The production of chemicals which are toxic or irritants to consumers
Method of Evolution Mutation
The source of all new alleles
Batesian Mimicry
Unprotected species resembling a protected species -both species possess boarding coloration -color as well as structure is mimicked -unprotected mimics are smaller in number
Flower Reproductive Process Dispersion
Wind (helicopters) Animals (insect) water (coconuts)
Flower Petals Function
attract pollinators
Flower Petals Description
big, bright, showy
Flower Carpel (Pistal) Description
central organ of the flower located inside of the stamen ring
Adaptations found in animals Chemical Defenses Warning coloration
coloration which allows an organism to stand out in their surroundings
Flower Stamen Parts
filament: holds anther anther: positioned near stigma and produces pollen
Method of Evolution Selection Pressure
forms of natural selection (environment)
Method of Evolution Selection Pressure Disruptive Selection
individuals with either extreme variation of a trait have greater fitness than individuals with the average form of the trait
Flower Stamen Description
long, thin, tall surrounding pistil
Antibiotic Resistance
occurs when bacteria change in a way that reduces the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections.
Hardy Weinburg Equilibrium Allelic Frequencies
p=dominant allele q=recessive allele equation: p+q=1
Hardy Weinburg Equilibrium Genotype Frequencies
p^2=homozygous dominant 2pq=heterozygous q^2=homozygous recessive equation: p^2+2pq+q^2=1
Flower Sepals Function
protects budding flower
Flower Sepals Description
small green leaf-like at the base of flower
Adaptations found in plants Chemical Defenses herbivore response
some herbivores have themselves adapted to the defensive adaptations of plants. They have either adapted the ability to breakdown defensive chemicals or to use the chemicals to their own defense
Flower Carpel (Pistal) Parts
stigma: very end of carpel (catches pollen) style: long thin tube (contains pollen tube) ovary: round bulbous base (contains ovules/eggs)
Adaptations found in animals Mechanical Defenses
structural changes
Flower Reproductive Process Fertilization Definition
the fusion of sperm (from the pollen grain) and the egg (inside the ovule) to produce an embryo
Flower Reproductive Process Pollination
the transfer of pollen from the anther of one flower to the stigma of another flower
Mullerian Mimicry
two protected species resembling each other advantage- power in number