Human Development, Variation, and Cell Biology

Vocabulary flashcards covering human foetal development, types of variation, the menstrual cycle, plant fertilisation, characteristics of life, and reproductive anatomy.

4 weeks (Embryo)

The embryo is $6\,\text{mm}$, the heart and other organs begin to grow, and the heart beats.

9 weeks (Foetus)

Arms grow, eyelids begin to form, and it is now considered a foetus.

12 weeks

The fetus starts to look more like a baby, starts to move, and is about $60\,\text{mm}$ long.

20 weeks

The fetus is about $150\,\text{mm}$ long, begins kicking, and can hear sounds.

Inherited variation

Features or diseases that have been passed from parents.

Environmental variation

Features you have changed or added to your appearance.

Continuous variation

Variation with no distinct categories that doesn't stay the same and is heavily influenced by the environment.

Menstrual cycle (Days 1–7)

The lining of the uterus breaks down and is lost if the egg isn't fertilised.

Menstrual cycle (Days 6–13)

The lining of the uterus regrows and is made up of spongy tissue.

Ovulation

The process on Day 14 where an egg is released and is ready to be fertilised.

Fertile

The period (typically Days 15–28) after an egg is released when a person can become pregnant.

Factors affecting foetal development

Behaviors such as drinking, drugs, and smoking.

Fertilisation (in plants)

When a bee carries pollen containing the male nucleus and it travels down the style (pollen tube) to the female nucleus.

Movement

A characteristic of living things involving walking around or plants moving to face the Sun.

Respiration

Using energy from eating, thinking, and moving.

Sensitivity

How organisms change to suit the environment.

Growth

The process of an organism getting bigger.

Reproduction

The process of creating a new generation.

Excretion

Waste leaving the body.

Nutrition

Eating healthy food.

Unicellular organisms

Organisms that are made of 1 cell.

Multicellular organisms

Organisms that are made of multiple cells.

Organ system

A group of different organs working together to carry out a job.

Animal cell components

Includes the nucleus, cytoplasm, mitochondria, ribosomes, and cell membrane.

Plant cell components

Includes the nucleus, cytoplasm, mitochondria, ribosomes, vacuole, and cell wall.

Male reproductive key words

Sperm duct, prostate gland, urethra, penis, scrotal sac, and testes.

Female reproductive key words

Oviduct, ovary, vagina, cervix, and uterus.