Natural selection and GM Flashcards
Classification
Grouping organisms according to similarities in their characteristics and making evolutionary links
How are organisms classified?
Based on their physical characteristics and a series of ‘yes’ or ‘no’ questions relating to a specific characteristic
What are the 5 kingdoms?
- Animals
- Plants
- Protista
- Prokaryotes
- Fungi
Animals: Characteristics
- Multicellular
- No cell walls
- Complex cell structure with nucleus
- Eukaryotes
Animals: Examples
- Spiders
- Birds
- Insects
- Humans
Plants: Characteristics
- Multicellular
- Eukaryotic
- Have cell walls made of cellulose
- Have chlorophyll so can photosynthesise
- Venus flytraps live in conditions with bad soil so they supplement by eating flies
Plants: Examples
- Trees
- Flowers
- Bushes
Fungi: Characteristics
- Mostly multicellular
- Eukaryotic
- Can’t photosynthesise
- Eat by breaking down external material such as wood or plants
- Are saprophytic feeders
- Some are unicellular such as yeast
Fungi: Examples
- Yeast
- Mushrooms
Protista: Characteristics
- Mostly unicellular
- Complex cell structure with a nucleus
- Some, like algae, are multicellular
Protista: Examples
- Amoeba
- Euglena
- Algae
Prokaryotes: Characteristics
- No nucleus, DNA free
- Unicellular
- Simple cell structure
Prokaryotes: Examples
- Ecoli
- Tuberculosis
Genus
- First part of the scientific name
- (e.g. Homo)
Species
- Entire scientific name
- (e.g. Homo sapiens)
The Classification Ladder
(Kids prefer cake over fancy green salad)
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What are the three domains?
- Prokaryotes
- Eukaryotes
- Archae
Why are Archae and Prokaryotes different?
- Archae have a different DNA sequence to prokaryotes and bacteria
What is a domain?
- A classification group that is bigger than a kingdom
What is genetic analysis?
- The study of DNA and genes and comparing it with other organisms to find a common ancestor
What is Selective Breeding?
- Humans selecting and breeding organisms with desirable characteristics to produce offspring with the desirable characteristics
What is Natural Selection?
- It is when certain organisms of a species gain a genetic mutation that makes them more likely to survive when a selection pressure comes. This leads to them living longer, being more likely to have offspring and then passing on the mutated genes that allowed them to survive and over millions of years, filling the entire population with this more useful characteristic
What is a Selection Pressure?
- External agents that affect an organism’s ability to survive in a given environment
- e.g. Predation, disease, competition for resources
When was Ardi?
4.4 million years ago
When was Lucy?
3.2 million years ago
Problems with selectice breeding (3)
- Can reduce the gene pool
- Can cause health problems as greater chance of genetic defects
- Reduced variation can increase susceptibility to disease
Clone
Definition
An organism with the exact genetic copy of another organism
Is done by mitosis
Advantages of Tissue Culture (4)
- Many genetically identical plants can be produced fast
- Desirable characteristics are guaranteed to be maintained
- Rare plants can be saved from extinction
- Can be grown all year round
Disadvantages of Tissue Culture
- No evolutionary potential
- Susceptible to genetic diseases
- Vulnerable to pests
How does Tissue Culture work (4)
Steps to grow Animal Cells
- A piece of tissue is taken
- The cells are seperated using enzymes
- The single cells are placed in a growth medium
- Culture is put into an incubator at optimum temperature, pH and oxygen concentration
Agrobacterium
Definition
A soil bacteria that can infect plant cells
