LIFE ON EARTH

UNIT 1: LIFE ON EARTH

1.1 CONDITIONS NECESSARY FOR LIFE

• Mild temperatures: – 150 C– Right distance to the Sun– Atmosphere with gases (H2O, CO2)

• Liquid water: Hidrosphere• Atmosphere

– Air: oxygen, carbon dioxide for plants and animals

– Magnetosphere: filter against harmful radiation.

• Geosphere: surface that provides:– Soil, water and mineral salts

Possible exam questions

• What are the characteristics of the Earth that make life possible?

• Why do you think there is no life in other planet of our solar system?

• Explain how the atmosphere causes that mild temperature.

1.2.What are living beings like?A. Similar chemical composition:

– Inorganic biomolecules: water and minerals

– Organic biomolecules: carbohydrates, lipids, proteins, nucleic acid (DNA)

B. Made up of cells– Cell theory:

• All living beings are made up of one or more cells

• Cells are the smallest units capable of the three vital functions

• All cells come from other cells

C. Three vital functions: HOMEWORK: complete the outline p.13

1.2.What are living beings like?

Types of nutrition

Autotrophic nutrition (Plants)

Heterotrophic

nutrition (Animals)

Types of reproducti

on

Sexual reprodution

Asexual reproductio

n

Possible questions• Write the three arguments of cell

theory• What are the inorganic

molecules of living beings?• What are the organic molecules?• Explain the three vital functions.• Fill in the blanks• Classify the living things by their

type of nutrition

1.3 Cells and cell types HW. Complete the outline at home.p.14,15) • Basic structure of a cell

– Plasma membrane:– Cytoplasm:– Genetic material:

• Types of cells– Prokaryotic cells:– Eukaryotic cells:

• Plant cells• Animal cells

• Cells (website with links)

• What are the differences between a prokaryotic and an eukaryotic cell?

• Draw a prokaryotic cell and write the name of its parts.

• Draw an eukaryotic cell and write the name of its parts.

• Complete an organelle chart with the functions.

Possible questions

OrganellesRibosomes• Manufacture proteinsLysosomes• Digest substances

Mitochondria• Produce the energy required by the cell

Chloroplast• Carry out photosynthesis

Large vacuoles• Store water

Cell wall• Rigid wall to protect the plant cell

Centrioles• Intervene in cell division

More questions• What are the differences

between an animal cell and a plant cell?

Plant cell Animal cell

NUTRITIONINTERACTIONREPRODUCTION

1.4 Vital funtions

1.4 Vital funtionsA. NUTRITION FUNCTION

– Processes that living beings carry out to acquire the substances they need to build new cell material and obtain energy

– The processes are: Obtaining nutrients, respiration, distributing substances and excretion.

Nutrition

Obtaining nutrients

Respiration

Distributing

substances

Excretion

Possible questions• How many processes are involved

in the nutrition function?• What does obtaining nutrients

mean?• What two concepts respiration

means?• How does our bodies distribute the

nutrients, the air and the waste?• What is the system that carries out

excretion?

OBTAINING NUTRIENTS• This process can be

autotrophic or heterotrophic.

• AUTOTROPHIC: nutrients are obtained through photosynthesis, using energy from the sun

• HETEROTROPHIC: nutrients are obtain from food from the environment

HETEROTROPHIC

AUTOTROPHIC

RESPIRATION• It is a process that

includes two other processes:– Breathing; taking

in oxygen and expelling carbon dioxide.

– Cell respiration: in mitochondria, the oxygen is used to produce energy from the glucose. Carbon dioxide is expelled.

DISTRIBUTING SUBSTANCES

• In multicellular organism, there is a circulatory system to transport substances between the different parts of their bodies.

EXCRETION• It is the process by

which the waste generated is eliminated from the organism

1.4 Vital funtionsB. INTERACTION

Allows living beings to receive information from their surroundings and from the inside. They react appropiately to the infromation.Steps

Perception of the stimuli

Processing and

coordination

Executing responses

.

B The interaction function processes

1: Light makes a bird visible to the cat. The bird also emits sound vibrations (chirping).

2: The visual and acoustic signals reach the cat’s sensory organs.

3: The sensory organs send the information they receive to the central nervous system.

• First, the receptor organs of living things capture information and send signals to the processing centres.

The central nervous system processes the information received and produces a suitable response (there is a bird there and I’m going to try to catch it).

• Then, the coordination centres process the signals from the receptors and prepare a response.

B The interaction function processes

The cat’s muscles, part of its locomotor system, receive the order to respond and carry out movements in order to try to catch the prey.

• Finally, the effectors receive the signals from the coordination centres and carry out the response.

B The interaction function processes

Questions for interaction

Imagine the following situations and explain what happens in three steps, specifying all the actions that take place in every step.

A. B

1.4 Vital funtionsC. REPRODUCTIONDef: Is the capacity to give life to other beings similar or identical to themselves.

ASEXUAL- Only one individual

- Offspring is identical

SEXUAL- Two individuals-Sexual cells and

gametes-Offspring is similar,

not identical

Offspring: descendencia

• The king is a philosophe, with a lot of class that orders for his family genres of good species.

• El rey es un filósofo de mucha clase que ordena para su familia géneros de buena especie.

• Taxonomy: classification of living beings in categories (taxon)

• KINGDOM, PHYLLUM, CLASS, ORDER, FAMILY, GENUS, SPECIES

• Link to “The tree of life”

1.5 The classification of the organisms

Scientific names• Species: group of individuals with similar

characteristics which can produce fertile offspring.

• Carl Linnaeus developed the idea of scientific names in the 18th century.

• Genus in capital letter, second name in low case.

• Species is the two names

Complete the taxons

• What is a scientific name? How is it written? Give an example.

(Next unit)

1.6 The 5 kingdoms