7J Genes Flashcards
What is the scientific definition of a species?
A group of organisms that can reproduce together to produce fertile offspring
Why do organisms have a scientific name?
So the species has the same name all over the world no matter what language is spoken.
What is the scientific name for humans?
Homo sapiens
The scientific name for a dog is Canis familiaris- what is the name of the genus?
Canis
What is continuous variation?
A feature that changes gradually over a range of values
What is the name of the graph that shows continuous variation?
Bell curve
What is discontinuous variation?
When individuals have features that fall into specific categories.
What type of graph can be drawn to show discontinuous variation?
Bar chart or histogram
Identify the 2 causes of variation.
Genetic and environmental
What might animals in the wild fight for?
Food, water, mates, territory
Name one physical trait caused by the environment.
Scars, tattoos, tanned skin, shaved head, dyed hair
Which type of variation cannot be changed?
Genetic
Name the male sex cell.
Sperm
Name the female sex cell.
Egg
Name two features that can be controlled by both forms of variation.
Height and Weight
Name two physical traits only affected by genetics.
Natural eye colour, natural hair colour, blood group, genetic diseases.
What might happen if all organisms were the same (no variation)?
They may die out if the environment changes
Why did the Dodo evolve to be a flightless bird?
It had no natural predators on the island
Why did the Dodo go extinct?
It was hunted by humans
Why do peacocks with large bright feathers have an advantage over other peacocks?
They are more likely to attract a mate
What is an albino?
A pure white animals
What does the term antibiotic resistant mean?
Not killed by antibiotics
Why are antibiotic resistant bacteria a problem in hospitals?
Bacterial infections are common and cannot be treated
Name an antibiotic resistant bacteria.
MRSA
What does the term extinct mean?
There are no individuals of that species left
Name 2 reasons a species may become extinct.
New diseases, predators, competition for resources, changed in the environment or catastrophic events.
Where did the meteor land that caused the extinction of the dinosaurs?
Chicxulub in Mexico
When did the meteor land that caused the extinction of the dinosaurs?
65.5 million years ago
Why did the volcanism at the Deccan traps affect the atmosphere?
It released dust and ash into the atmosphere which blocked sunlight and reduced temperature.
Where can we find evidence of extinct species from the past?
The fossil record
Why are humans destroying large areas of woodland and rainforest?
We require more resources and land.
Name 2 things humans are doing to stop species from going extinct.
Protecting habitats, maintaining populations of endangered species in zoos, breeding programmes and planting trees.
What controls the female fertility cycle?
Hormones
What does the female reproductive system receive to create a fertilised egg?
Sperm
Where does the foetus develop in the female reproductive system?
Uterus or womb
What are the 2 main purposes of the female reproductive system?
To produce egg cells and to provide an environment for growing a foetus.
What is the function of the vagina?
Muscular tube to stretch to allow the baby to pass.
What is the function of the cervix?
An opening to allow sperm into the uterus
Describe the walls of the uterus.
Thick and muscular
What is the function of the ovary?
To produce egg cells
How long does an average menstrual cycle last?
28 days
What is the menstrual cycle controlled by?
Hormones
On which day in the cycle does a woman have her period?
The first day
What occurs on day 5 of the menstrual cycle?
The lining of the uterus builds up
On which day in the cycle is an egg released from the ovary?
14
What happens to an unfertilised egg at the end of the cycle?
It leaves the vagina when the woman has her period
Which female hormone causes the lining of the uterus to thicken?
Oestrogen
Which hormones causes an egg to mature in the ovaries?
FSH
Name the hormone that controls growth and development of organs in males.
Testosterone
What is the function of the male reproductive system?
To produce millions of sperm and to transport them inside the female.
In which organ are the sperm cells produced?
Testicles
Why are the testicles held outside the body?
To keep sperm at the best temperature for them to function.
Where is semen produced?
Prostate gland
What is the function of the urethra?
The tube connecting the prostate gland to the penis
Name an organism that carries out external fertilisation.
Fish
When do plants produce pollen?
Only when stigmas are ready for fertilisation
Define the term ‘infertility’.
When a couple are unable to conceive a baby
Name 2 external factors that can cause infertility in women and men.
Excessive alcohol, drugs, long-term smoking, stress and sexually transmitted diseases can cause infertility.
What does the term ‘ovulation’ mean?
The release of eggs from the ovaries
Why would a blockage in the oviduct cause infertility?
It prevents an egg from reaching the uterus and being fertilised.
What does IVF stand for?
In Vitro Fertilisation
What hormone is the woman injected with in IVF?
FSH
Where does fertilisation occur in IVF?
Outside the body (in a lab)
What happens to the fertilised egg cells?
They are implanted into the lining of the mother’s uterus
How long does it take a human foetus to grow from a fertilised egg?
38 weeks
What term is used to describe the period of growth from egg cell to foetus?
Gestation
What does the mother provide for the developing foetus?
Nutrients and oxygen
For how long, during the growth process, are all the cells the same?
First two to three weeks
What is the name for cells that can become any other type of cell?
Stem cell
What is an embryo?
A ball of cells
What is used to create images of the foetus?
Ultrasound
What is the placenta produced from?
The original ball of cells
