Variation and evolution

Created by

Jess

Cards (38)

Variation
Differences is the characteristics of individuals
What can cause variation
Genetic causes
Environmental causes
Mix of both
How do new phenotypes variants occur
Mutations
What are the effects of mutations
Most have no effect on phenotype
Some influence phenotype
Very few lead to new phenotype
What is selective breeding
Breeding plants and animals for particular characteristics
Selective breeding process
Choose good parents
Breed them
Choose good offspring
Breed again
Repeat
Consequences of inbreeding
Inherited defects and diseases
Genetic engineering
Modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic
How have plant crops been genetically engineered
To be resistant to diseases
Produce bigger fruits
To give higher yeilds
How have bacteria been genetically engineered
To produce useful substances
What are enzymes used for in genetic engineering
Cut out the required gene
What is used to transfer the required gene into the new cell in genetic engineering
a vector
What is sexual reproduction
Fusion of male and female gametes
What type of cell division is involved in sexual reproduction
Meiosis
What type of cell division is involved in asexual reproduction
Mitosis
What is meiosis
Cell division that produces 4 daughter cells, each with a single set of chromosomes
What are the male and female sex chromosomes in humans
XY- Male
XX - Female
What are the male and female gametes in flowering plants
Pollen - Male gamete
Ovule - Female gamete
What is the genetic material in cells called
DNA
What is the structure of DNA
two complementary strands forming a double helix shape
Gene: Small section of DNA
Allele: different forms of the same gene
Recessive allele: allele that needs to be present twice to be expressed
Dominant allele: allele that is always expressed
Genome: the entire genetic material of an organism
Homozygous: 2 of the same alleles present
Heterozygous: 2 different alleles present in an organism
How many chromosomes do normal human body cells have?
23 pairs (46)
What is evolution
Change in the inherited characteristics of a population over time through natural selection
Theory of evolution by natural selection
The organisms that are best adapted to their environment are most likely to survive
What are fossils
Remains of organisms from millions of year ago
How might fossils be formed
Parts of an organism do not decay
Benefits of the fossil record
Can learn how species changed
Problems of the fossil record
Many early organisms were soft bodied so few fossils
What is extinction
No individuals of a species are still alive
Factors contributing to extinction
Predators
Diseases
Changes in habitat
What is the bionomial system
Naming of organisms by their genus and species
Why can bacteria evolve rapidly
They reproduce at a fast rate