Inheritance and selection Flashcards
Name four examples of inherited characteristics.
Genetic diseases
Natural hair colour
Eye colour
Blood group
During fertilisation, male and female ____________ fuse and their ______________ combines.
Gamete nuclei
Genetic information
Name four examples of environmental characteristics.
Hair length
Freckles
An accent
Body weight
Inheriting characteristics occur in both…
Plants and animals
What is a species?
A group of similar organisms that can produce offspring which will also be able to reproduce.
What is a variety.
A group of plants or animals that are the same species but with clear differences within their characteristics.
What is selective breeding?
Selective breeding is where you breed animals and plants so they eventually produce a certain characteristic.
What is cross- breeding?
Cross breeding is where you breed two species to create a new species.
What are the steps of fertilisation?
An egg cell contained in an ovule is found in an ovary.
The egg cell is released from the ovary and it travels down the oviduct.
Sperm cells are made in the testes.
During sex p, sperm cells are released and travel through the females uterus.
The sperm cell joins with an egg and fertilises it.
A fertilised egg cell is produced, with genetic information from both the mother and father.
What happens during plant fertilisation?
Pollen grains are produced by the male part of the plant.
A pollen tube grows from a pollen grain.
Pollen grains are carried by insects or the wind.
Pollen grains land on the stigma of other flowers.
The nucleus from the pollen grain enters the egg cell and fertilises it.
The fertilised egg cell grows into a seed.
How many chromosomes are there in a human body cell?
46 chromosomes
23 pairs
What is a chromosome ?
A very long coil of DNA which is a double helix shape. DNA encodes all of the inherited characteristics of each person.
What is cell division?
Once the two gametes are fused together, they split in half again and again, multiplying each time, until they grow into an embryo.
How are identical twins formed?
Half of the multiplying cells break off and two embryos are formed.
How are non- identical twins formed?
When two sperm reach two eggs at exactly the same time, cell decision happens with two eggs instead of one.
