evaluation

evolution

the gradual change in heritable characteristics of organisms over may generation

hierarchy of classification

kingdom
phylum
class
order
family
genus
species
king Philip come over for good soup

population

a group of members of the same species living in the same place at the same time

species

a group of organisms that closely resemble each other and can interbreed to produce fertile offspring

binomial system of nomenclature

to scientifically name an organism you simple write their genus then species
genus name must be capitalized and species name is lover case

what are the two types of biodiversity

species diversity genetic diversity

species diversity

the number of different species in an ecosystem eg fish coral sharks in a reef ecosystem

genetic diversity

the range of genetic characteristic within a single species eg blue green brown and hazel eyes in humans

microevolution

evolutionary changes that occur over relatively short period of geological time (such as between generations) and results in changing the genetic diversity (variation )within a species

how dose microevolution (changing of genetic diversity) occur

mutations
genetic drift
gene flow
natural selection

gene pool

the totality of gens (and their particular alleles ) within a population

mutations

a change in the genetic code in DNA can lead to a change in the protein that is coded for and produced by the segment of DNA (gene)
source of new alleles within a populations
new alleles = new proteins = new traits
only way to generate new alleles

what are the three different types of mutations that can occur

addition/intersection
deletion
substitution

addition/insertion

where one(or more) nucleotides are inserted/added into the DNA sequence, leading to a change in the genetic code
can be either

deletion

where one (or more ) nucleotide are deleted in the DNA sequence, lead to a change in the genetic code
can also be frameshift or non-frameshift mutation

Addition/Insertion

where one (or more) nucleotides are directly replaced in the DNA sequence, lead to change in the genetic code

frameshift

insertion of a number of nucleotide which are not divisible by the three

non-frameshift

insertion of a number of nucleotide divisible by three

what are the effect of mutations

negative- mutated DNA could lead to an allele that codes for a disease/less effective protein

positive -mutated DNA could lead an allele that codes for a better/more effective protein

neutral(no effect)- mutated DNA dose nothing/very little to the overall protein structure

genetic drift

the change in frequency of alleles in a population due to random sampling(random events) usually over a short period of time
allele frequencies can change dramatically
eg fires or floods

gene flow

the movement of individual( and their alleles) into or out of a population as a results of immigration and emigration (also called gene migration

immigration - of individuals into a population has the ability to increase number of alles in a population(not always the case but it may)
emigration may lead to a decrease in alleles presence or eliminate an allele altogether from a population

adaptation

a trait that aids the survival of an organism in its environment

structural adaptation

a structure or physicals appearance of an organism that aids it survival in a particular environment
eg wings for flight

behavioral adaptation

a behavioral trait of an organism that aids it survival in a particular environment
eg huddling together for warmth

physiological adaptation

An involuntary (cellular) process that an organism undertakes to aid its survival in a particular environment.
eg sweating to cool down

4 major principle of natural selection

Variation within the initial population-
Application of a selection pressure
Differential Reproduction
Change in allele frequencies of the population.

NS 1 variation within the initial population

Initially there must be variation of alleles (genotypes) and therefore variation of traits (phenotypes) in the population.

NS 2 application of a selection pressure

External agents which affect the ability of an organism to survive and reproductively successful are said to apply a selection pressure.

Types of selection pressures include:
Resource availability:  Presence of sufficient food, habitat and mates
Environmental conditions:  Temperature, weather conditions or geographical access
Biological factors:  Predation and disease

NS 3 differential reproduction

Organisms with beneficial adaptations (phenotypes) will be more likely to survive long enough to reproduce and pass on their genes.
Organisms without these beneficial adaptations (phenotypes) will be less likely to survive and pass on their genes.

NS 4 change in allele Frequencies

As a result of differential reproduction, features which confer a survival advantage are more likely to be passed on to subsequent generations

selective agent

a biotic or abiotic factor within an organism’s environment which reduces (puts pressure on) an organism’s ability to survive.

The effect of a selective agent on a population is known as the selection pressure.

selective agents

shelter
water availability
food availability
sunlight
pollution
temperature
mating partners
predictors
diseases

macroevolution

Macroevolution describes evolutionary relationships that occur over a relatively long period of geological time and results in diversification between species.

divergent evoulation

When populations with a recent common ancestor accumulate so many differences over a long time scale and they branch away from their common ancestor to form new species.
The process by which a new species is created is called speciation.

convergent evolution

When two or more distantly related species adopt similar adaptations (behavioural, structural or physiological) in response to overcome common environmental pressures.

The two organisms did not inherit their adaptations from their common ancestor

co-evolution

Where two organisms can reciprocally affect each other’s evolution.

E.g. The co-evolution seen between a flowering plant and a pollinating bird.

steps of speciation

For Speciation to occur, you must have the following three steps:
There must be strong variation of alleles within the initial population.

There then must be isolation of a breeding population from the original population by a geographic barrier.

There then must be different selection pressures that affect and change each populations gene pool over a long period of time.

how to write a natural selection paragraph

a. The variation of alleles (traits) in the initial population
b. The selective agent
c. The selection pressure
d. Which allele (trait) do you think is more favored?