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