Topic B6 - Inheritance, Variation And Evolution Flashcards
What does MEOISIS do?
Meiosis produces cells with half the normal number of chromosomes.
What is a charecteristic of gametes from MEIOSIS?
All the gametes produced by meiosis are genetically different.
What are the stages of MEIOSIS?
1) The cell duplicates its genetic information
2) The cell divides and each new cell has one copy of each chromosome
3) Both cells divide again to make four gametes. Each gamete only has a single set of chromosomes.
How are gametes formed?
Gametes are formed by meiosis in the reproductive organs.
Fertilisation of GAMETES:
Gamete (sperm) + Gamete (egg)
= offspring (fertilised egg)
What happens to offspring during FERTILISATION?
Offsprings normal number of chromosomes are restored
The fertilised cell divides by mitosis many times to form an embryo.
Who created the LINNAEAN SYSTEM?
Carl Linnaeus
What does the LINNAEAN SYSTEM do?
Organises organisms by their characteristics and structures into groups.
What groups are in the LINNAEAN SYSTSEM?
In this order:
~ Kingdom ~ Phylum ~ Class ~ Order ~ Family ~ Genus ~ Species
Binomial naming system
Scientific names are split up into two parts:
First (Genus) - Second (Species)
e.g humans are:
Homo sapiens
(Genus) (Species)
What are THREE developments in Classification?
1) Better Microscopes
2) Improved Chemical Analysis
3) New Models
What is the ‘Three-Domain System’
~ 1) Bacteria - true bacteria (prokaryotic)
~ 2) Archea - a different type of prokaryotic cell, usually found in extreme places
~ 3) Eukaryota - includes protists, fungi, plants and animals
What do EVOLUTIONARY TREES show?
Shows how scientists think differnet species are related to each other.
How do scientists complete EVOLUTIONARY TREES?
With DATA SOURCES:
LIVING SPECIES:
~ Current classification data
EXTINCT SPECIES:
~ Fossil Data
A pair of the same alleles is called
Homozygous
