Biology Genes Flashcards
Differences in characteristics are known as…
Variation
Define a species…
A group of living things that have more in common with each other than with other groups. This allows them to mate to produce fertile offspring.
What is meant by inherited variation?
Variation (differences) between organisms caused by genetic factors.
Define variation…
Differences within and between species.
What is meant by environmental variation?
Variation (differences) between organisms caused by your surroundings/environmental factors.
Name an inherited characteristic that can be affected by environmental variation…
Height. You might inherit the characteristic to be tall, but if you eat a poor diet, your rate of growth may be reduced.
List some inherited characteristics that are not affected by environmental variation.
Eye colour
Blood group.
Genetic diseases.
Whether you have lobed or lobeless ears.
What is meant by discontinuous variation?
Where differences in characteristics between living things can only be grouped into categories.
What is meant by continuous variation?
Where differences in characteristics between living things can have any numerical value.
Give an example of discontinuous variation.
Gender. There are only two possible categories: male or female.
Give an example of continuous variation.
Height. Everyone’s height is a value between the shortest person in the world and the tallest.
Other examples: body mass, hair length and arm span.
State the type of graph that should be used to plot discontinuous data.
Bar chart.
State the type of graph that should be used to plot continuous data.
Histogram.
Continuous variation usually produces a curve. What is it called?
It is known as a normal distribution.
Characteristics that occur as a result of both environmental and inherited variation usually show ………. variation.
Continuous.
State what is meant by adaptation.
Characteristic that helps an organism survive in its environment.
How might a plant be adapted to live in the desert?
A waxy layer that covers the plant - this reduces water escaping from the plant.
Stems that can store water.
Widespread roots to collect water from a wide area.
Spines instead of leaves - this gives a smaller surface area to reduce water loss. Spines also prevent the plant being eaten.
State two advantages of trees losing their leaves in winter?
It saves energy.
The fallen leaves provide a layer of warmth and protection around the base of the tree. The tree can reuse the nutrients from these leaves too.
State three ways that different animals adapt to the winter.
Hibernation - animals like bears find somewhere wam to sleep through the winter.
Migration - animals like birds move somewhere warmer, or somewhere with more food.
Grow thicker fur - animals like sheep are kept warm by their thick coat.
How does a snowshoe hare adapt to its environment throughout the year?
In winter it has white fur which helps it blend in with the snow - this helps it escape from predators and advance on its prey.
In summer, its fur is reddish-brown which helps them to blend in with rocks and earth in mountain forests. It increases its chance of survival.
State what is meant by adolescence.
Adolescence is the period of time when a child changes and grows into an adult.W
What is puberty?
The physical changes that your body goes through during adolescence.
Name some emotional changes that occur during adolescence?
Moody
Self-conscious
Angry
Name some physical changes that occur during puberty?
Pubic hair grows
Underarm hair grown
Body smell becomes stronger
Growth spurt
State changes that happen only to girls during puberty.
Girls:
breasts develop
Ovaries start to release eggs
Periods start
Hips widen
State changes that happen only to boys during puberty.
Voice breaks - gets deeper
Testicles and penis get bigger
Testicles produce sperm
Shoulders widen
Hair grows on face and chest
What causes puberty?
Changes are caused by sex hormones. These are chemical messengers that travel around your body in the blood.
Where are female sex hormones made?
In the ovaries.
