How you and I changes the environment:

Photosynthesis makes the planet liveable. Photosynthetic organisms remove carbon dioxide from the air. Carbon dioxide is transformed into other organic compounds, supporting life. While animals exhale carbon dioxide, trees and algae act as a carbon sink, keeping most of the element out of the air. Here is a fun video about Photosynthesis:

A description of taxonomy

Reproduction

Understanding human development and puberty

- Puberty is the process by which a girl or a boy become sexually mature, i.e. able to sexually reproduce.

- Puberty marks the transition between childhood and teenage years.

- It is a period marked by important physical and psychological changes, and often the time when young individuals start to explore their sexuality.

Puberty in girls

Puberty in girls happens between 10-14 years-old and is characterized by:

- development of breast

- hair growth in pubic areas and armpits

- starting of menstruating cycles

- concerns about body-image and relation with peers

- changes in self-esteem and self-confidence

Puberty in boys

Puberty in boys happens between 12-16 years-old and is characterized by:

- Increasing size of penis and testicles

- hair growth in pubic areas, armpits and on the face

- increasing of muscle mass

- deepening of voice

- increased aggression or assertion

- changes in self-esteem and self-confidence

The main body organs

- The body needs all organs in order to function properly.

- The main systems of the body are:

• The digestive system which contains the stomach and intestine, and extract nutrients and resources from ingested food;
• The nervous system containing the brain and using the nerves to transfer information transfer between different body parts and the brain, allowing for example to sense and move;
• The respiratory system containing the lungs, which extract oxygen from the air;
• The cardiovascular system containing the heart and blood vessel allows the transport of elements such as nutrients, hormones and oxygen all over the body;
• The reproductive system containing the sex organs like the ovaries and testes and is used for reproduction

Feelings, relationships and sex

- Developing romantic feelings for someone else is a natural part of our lives.

- Romantic relationships are usually considered a psychological need and are an integrant and healthy part of our lives, although its nature varies with individuals.

- Having sexual intercourse with a consenting partner is a natural and healthy part of our life, although its nature varies with individuals.

Consent in romantic relationships and sexual intercourse

- Consent is the notion by which an individual is able to understand and to freely and willingly accept the consequences of an action.

- It is important to make sure that every person involved in a relationship or sexual intercourse are willingly and freely consenting.

- Understanding the consent or non-consent of a person is best reached through showing empathy, patience and understanding.

- In many countries, non-consensual interactions are forbidden and punished by the law.

Developing romantic relationships

- Romantic relationships can be developed by any individual for any other individual, independently of gender, ethnies, identity, condition,...

- The forms and shapes of romantic relationships are specific to individuals.

- To form a healthy relationship, it is important that all persons involved understand the nature of the relationship and agree to it.

Sexual intercourse

- A sexual intercourse comprises all acts and actions meant for sexual pleasure and/or reproduction, either alone or between consenting partners.

- Sexual intercourse should be pleasurable to all persons involved, and for peace of mind it is important to understand the possible outcomes of a sexual intercourse.

- A sexual intercourse between a person with a penis and a person with a vagina can lead to pregnancy. If pregnancy is not wanted, it is important to use effective contraceptive methods such as condoms or contraceptive pills and devices.

- Sexual intercourse with other partners can lead to the transmission of diseases. The best way to avoid sexually transmitted diseases during sexual intercourse is to avoid penetration, or to use a condom on a penis if there is penetration.

Understanding biodiversity

• Biodiversity is a measure that represents the diversity of life, either in a local scale or at a global scale.
• Biodiversity is highly dependent on local conditions, and some regions have a higher biodiversity than others.
• Tropical forests have the highest biodiversity on Earth, representing about 10% of land mass and including about 90% of Earth's biodiversity.
• Selection and evolution can explain the biodiversity we observe (see lesson on evolution here).
• Humans activities are often a threat to biodiversity, and lowered biodiversity can lead to ecological collapse (see humans' impact on nature here).

Ecosystem services

• Healthy, functional ecosystems usually are self-sustained and allow the occurrence of many species.
• Some species, such as crops, pollinating insects or trees are used by humans to produce resources like food or raw materials.
• The benefits that ecosystems give to human societies is called ecosystem services.
• Losing biodiversity usually results in loss of ecosystem services.
• It is however possible to restore biodiversity through actions like planting forests or protecting areas.

Links for the videos:

What would happen if you wouldn't sleep? By: Colossal Cranium 

Biotechnology is the development of technologies and products based on living systems and organisms. It is at the crossroads of many disciplines such as engineering, genetics, and biochemistry. In its simple form, biotechnologies are about harnessing processes coming from living organisms and using them to make products, for example by using yeasts to make bread or fermentation to make biofuel. With the advancement of genetics and chemistry, biotechnologies are also use to make for example vaccines and medicines. 

What is taxonomy?
- Taxonomy is the science that arranges and groups organisms at different level.
- The basic unit of taxonomy is the species, but organisms are named after both their species and genus name. For example, wolves are Canis lupus. 
- The ensemble of all the species is called the tree of life.

UNDERSTANDING EVOLUTION

1. Organisms are adapted to live efficiently in their environment. For example, fishes can breath underwater while cats cannot: fishes are adapted to life in water.
2. Inside a species there can be variation in one trait, meaning that the trait is slightly different from one organism to another. For example, the peppered moth is a butterfly that can have wings either dominantly white or black, which allow them to hide on trees.
3. Changes in the environment means that different traits become more adapted than others. For example, in forests with most trees having dark trunks, the black version of the peppered moth survives better, and vice-versa. 
4. The change of a proportion of a trait is called evolution. It is thus populations that evolve (individuals never evolve!).
5. If the same species live in different environments, then they will eventually evolve into different species. This diversity in environments and the variation in traits is at the origin of diversity in the living world. For example, the peppered moth can eventually evolve into a black species and a white species, depending on the color of the trunks of the trees. 

DNA and the genetic code

- DNA is a chemical structure that stores biological information. It is the basic block of life and forms the genetic code.

- The genetic code of an individual contains all the information necessary for an organism to live, function and reproduce.

- Each species have their own genetic code, although there is always some variation and many species share parts of their genetic code with other species.

- Because the genetic code is heritable, individuals of the next generation will have code coming from the previous generation... and so on.

- This heritability means that specific traits can be prominent in one region and rare in another region. For example, blue eyes in humans are more common in northern areas and rarer the more we go towards the equator.

The genetic code is flexible

- The genetic code may give different instructions for a specific trait depending on other factors.

 - For example, in the European pond turtle the gender of an individual depends on the temperature at which eggs have been brood: under 25 degrees the broods are all-males, and over 30 degrees the brood are all females

- The expression of many traits depend on the environment. This is why even true-twins do not look perfectly alike.

Impact of human activities on the natural environment

- Live beings are typically adapted to their environment.

- Many human activities heavily disturb the natural environment, for example the extraction of resources, farming, the building of infrastructures...

- As a consequence, live beings might live in environments which are not adapted to them anymore.

- Human disturbances can be split in 2 categories: either human destroy the environment, or they act as predators.

- For example, artificial lighting creates a "forever day", but many animals need darkness to hide or hunt; the release of chemicals in ocean changes the physiology of fishes, such that males become females or the other way round; many animals are eating plastic because they think it is food.

- Human disturbances are the cause of the disappearance of many species.

Are we at the origin of a mass extinction?

Deep-sea life in Antarctica

- Life-forms are present in almost all environments of Earth, even in hostile environments like Antarctica.

- Because of its extremely difficult environment, Antarctica has been the last area to be accessed by Humans and is unique in its pristineness.

- Besides its hostile environment, the deep-sea of Antarctica is home to a flourishing life (see course on biodiversity here).

- The deep-sea of Antarctica is home to unique species all adapted to cold environment (see course on evolution here).

- Understanding the biodiversity of Antarctica can help us to understand how climate change impacts all biodiversity.

What is a virus?

- Viruses are structures made of proteins that need the genetic machineries of life forms to reproduce. Whether viruses are considered alive or not is still under debate.

- Specific viruses usually infect specific host species, and cross-species infections are rare. For example, viruses infecting plants cannot infect animals. Viruses infecting specific animals usually do not infect other animals (although it can happen, like with the HIV or the COVID).

- Viruses are often harmless to their host organism, but they can be at the origin of pathologies if they disrupt the functioning of their host organism.

- Detrimental infection by viruses are fight by the host organism through their immune system.

Immune system and pathogens

- Pathogens are agents, such as viruses or bacteria, that are disrupting the functions of an organism.

- Affection by a pathogen is at the origin of many diseases, but the immune system is what allows the organism to eliminate the pathogens.

- When affected by viruses, the immune system usually "remembers" how to fight future infections by the same virus: it is what provides immunity.

Vaccines and immunity

- Immunity is what allows the immune system of an organism to fight a pathogen before it does damages to the organism.

- Vaccines are using this system to create an immunity to a disease without having to suffer a pathology. 

- By mimicking a virus, vaccines create an immune response and induce an immunity without having to suffer the actual disease.

- It is extremely effective to reduce the occurrence of many viruses like cholera, hepatitis B, measles, polio, rabies, tetanus, typhoid... 

- One of the most impressive achievement of vaccines is the eradication of the smallpox, a virus which had a 30% mortality rate and has been officially eradicated in 1980.