biology evolution

Variation

Differences between organisms

Intra-specific

Differences between individuals in the same species

Inter-specific

Differences between different species

Genetic Variation

Variation that is determined by your genetic code

Genetic Examples

Eye colour, Hair Colour

Environmental

Variation determine by factors other than your genes

Environmental Examples

Presences of scars, tattoos

Genotype

Genetic makeup, your DNA sequence

Phenotype

Observable characteristics, result of your genotype and the environment interaction

Mutations

A change to the DNA sequence

Theory of Evolution

All of today's species have evolved from simple life forms that started to develop over 3 billion years ago

Evolution

The change in the heritable charactersitcs of biological population over successive generation

Evolution by Natural Selection Step 1

A random mutation occurs

Evolution by Natural Selection Step 2

The organisms with mutations are better adapted to their environment

Evolution by Natural Selection Step 3

This increases their chance of survival

Evolution by Natural Selection Step 4

Giving them more opportunities to reproduce

Evolution by Natural Selection Step 5

And pass on their successful genes to their offspring

Evolution by Natural Selection Step 6

Overtime the beneficial characteristic becomes more common and the species evolves

Selective Breeding

When humans artificially select the plants or animals that are going to breed

Process of Selective Breeding Step 1

Organisms with desirable traits are selected and made to breed

Process of Selective Breeding Step 2

The offspring are observed for signs of those desirable characteristics

Process of Selective Breeding Step 3

The best ones are then selected to breed to make more offspring with the desirable traits

Process of Selective Breeding Step 4

Continue this process over several generations. Eventually all offspring will have this characteristic

Issues with Selective Breeding

Reduces the genetic variation in the population, inbreeding, Causes health problems

Inbreeding

The breeding of individuals with similar characteristics

Jean-Baptiste Lamarck

He was a French naturalist who proposed a theory of 'use it or lost it'

Lamarck's Theory

Individual organisms changed as they adapt to their environment and passed on these changes to their offspring

Charles Darwin

English naturalist who proposed the Theory of Natural Selection

Alfred Russel Wallace

A biologist who co-published the Theory of Natural Selection with Charles Darwin

Darwin's critiques

Lack of complete fossil record and lack of explanation of the mechanism by which evolution could happen

Species

A group of similar organisms that can reproduce to give fertile offspring

Speciation

The development of a new species which occurs when populations of the same species become so signifcantly different they can no longer interbreed and produce fertile offspring

Process of Speciation Step 1

Populations of species are separated (isolated) due to physical barriers

Process of Speciation Step 2

Conditions on either side of barrier may be different/distinct which means that desirable characteristics are also different

Process of Speciation Step 3

Different characteristics will become more common due to natural selection operating differently on the populations

Process of Speciation Step 4

Eventually different populations have changed so much that they will not produce fertile offspring

Process of Speciation Step 5

The two groups have become separate species, Speciation has occurred

Darwin's Finches

A brilliant example of speciation caused by geographical isolation

Paleontology

The study of fossils

Fossil Record

The total number of fossils and their location found

Fossil

An imprint or remains of an organism in a rock

Fossilisation Step 1

An animal dies and falls to the seabed and gets covered by layers of sediment

Fossilisation Step 2

The sediment around it thickens and turns to rock

Fossilisation Step 3

The skeleton then dissolves and a mould is created

Fossilisation Step 4

The minerals crystallise inside the mould and a cast is formed

Fossilisation Step 5

The fossil gets exposed to the surface due to erosion and earthquakes

Extinction

The permanent loss of all members of a species

New Predators

This extinction event occurs when a new species enters an area and begins feeding on a different species that originally had fewer organisms eating it.

New diseases

This occurs when diseases arise naturally and can easily spread because the animals might live very closely together

Environmental changes

When the environment the species is in changes which can be caused by flooding, drought, snow and it can be the slightest of changes

Successful Competition

When an organism is better suited for their environment or have no competitors or predators which causes another species to die out

Mass Extinction

When a species vanishes quicker than it can be reproduced

Antibiotics

Medicine which is used to treat bacterial infections but not viruses

Superbugs

Strains of bacteria that have developed resistance to many different types of antibiotics

Antibiotic Resistance Step 1

A person is prescribed antibiotics. This could be for the wrong reasons such as, their infection being caused by a virus.

Antibiotic Resistance Step 2

The person takes the antibiotics until they are feeling better.

Antibiotic Resistance Step 3

As a result, the person stops taking the antibiotics before the course is finished.

Antibiotic Resistance Step 4

The population of bacteria is diminished. Only the bacteria that are resistant to the antibiotic are left.

Antibiotic Resistance Step 5

These antibiotic resistant bacteria are able to clone themselves until the whole population is resistant to antibiotics.

Antibiotic Resistance Step 6

Antibiotics are now no longer effective. Lots of time and money is spent trying to make new, stronger antibiotics.

Classification

The organisation of living things into groups according to their similarities and differences

Carl Linnaeus

Designed the Linnaean Classification

Linnaean Classification

It groups organisms according to structure and characteristics

Classification systems

Linnaean and Woese Classification

Kingdom, Phylum, Class, Order, Family, Genus, Species

Linnaean Classification

5 kingdoms

Plantae, Animalia, Fungi, Monera, Protista

Mammals

Animals that have fur or hair and produces milk

Birds

Animals that have feathers and beaks

Reptiles

Animals that have dry scales

Fish

Animals that have wet scales and gills

Amphibians

Animals that have moist skin, gills and lungs

Carl Woese

Developed the Woese Classification which added Domain to the Linnaean Classification

Woese Classification

Classified all organisms into three large groups called domains

Binomial Naming System

It uses the genus (first and uppercase) and the species (second and lowercase) of the organism

3 domains

Bacteria, Archaea, Eukaryota

Bacteria

True bacteria, cyanobacteria (photosynthesise)

Archaea

Primitive Bacteria

Eurkaryota

Cells containing nuclei

Evolutionary Trees

Uses evolutionary information which show relationships between organisms based on their common ancestors