EARTH AND LIFE SCIENCE

LIFE SCIENCE (FINALS)

Introduction to Biology
Biology
- Greek word “bios” means life, and “logos” which means to study
- Also known as life science
- Coined by Jean Baptiste-Lamarck
- Studies living things including their structure, composition, characteristics, functions, and
classification.
- Aristotle – Father of Biology
Different branches of Biology
o Anatomy - internal structures
o Bacteriology – bacteria
o Biotechnology – using biological processes for industrial production
o Botany - study of plants
o Conchology - shells
o Cytology – cell
o Ecology – relationship between living and non-living things
o Embryology – developmental patterns of an organism from zygote to birth
o Endocrinology – endocrine glands and their corresponding hormones
o Entomology – study about insects
o Ethology – animal behavior
o Evolution – change overtime
o Genetics - heredity, genes and variations
o Helminthology - parasitic worms
o Histology – tissues
o Ichthyology - fishes
o Immunology - immune system
o Malacology – mollusks
o Mammalogy – mammals
o Medicine - preventing, treating, or reducing disease
o Microbiology - microscopic organism
o Morphology – Form and shape
o Mycology – fungi
o Ornithology – birds
o Paleontology – fossil
o Parasitology – parasites
o Pathology – diseases
o Physiology – functions of organ and body systems
o Virology – virus
o Zoology – animals
Properties of Life (HOMAGRR)
HOMEOSTASIS
o The ability to maintain internal balance, or normal state of a body

Examples: body temperature regulation, blood sugar level regulation

ORGANIZATION
o Made up of one or more cells with complex structures and chemical processes.

Atom - it is the building block of matter. With subatomic particles:

Proton - positively charged particles
Neutron - no charge particles
Electron - negatively charged particles
Molecules/Compound - two or more atoms joined in chemical bonds.
Organelles - tiny organs of the cells that have specific function. They are known as little organs
and they are found inside the cell.
Cells - they are the building blocks of life. Basic unit of life. All organism are made up of cells.
Tissue - when cells of the same structure and function combine together.
Organ - when tissues of the same structure and function combine together.
Organ System - when organs of the same structure and function combine.
Organism - individual living things.
Population - it is a group of the same species living in the same area.
Community - different populations living in the same area.
Ecosystem - it is composed of living and non-living things interacting with one another.
Biomes - it is a region that is divided into categories based on the plants and animals that call it
home Scientists can identity a biome by defining the temperature range, soil type, and amounts of
light and water that are peculiar to that location and create niches for various species.
Biosphere - entire planet is thought of as an ecosystem
METABOLISM
o The sum of all chemical reactions that occur within an organism.
o The process of converting and releasing energy

Processes of metabolism:
Ingestion - process of taking in food substances
Digestion - process by which the body breaks down food into small molecules through
mechanical and chemical means.
 Respiration - process that delivers oxygen from the air to the body’s tissues and removes
carbon dioxide.
Excretion - process of removing metabolic wastes from the body, which are byproducts of
metabolism.
Types of metabolism:
Catabolism (Cut) - breakdown of large molecules
Anabolism (Add) - synthesis of large molecules
ADAPTATION
o Organism's mechanism to be better fit and to survive the conditions of their environment.

Mimicry - resemblance between on organism and another object or species.

Types of mimicry:
Batesian mimicry - harmless mimics harmful
Mullerian mimicry - harmful mimics another harmful
Aggressive mimicry - predators or parasites share some of the characteristics of a
harmless species.
Evolution - it is a change over time. It is responsible for variation and biodiversity.
Types of evolution:
Divergent evolution - occurs when two or more related species become more
dissimilar over time
Convergent evolution - occurs when two different organism develop similar
characteristics as a results of same needs in the environment
Parallel evolution - occurs when related species develop similar traits independently
because they have similar ancestral traits
Evidence of evolution:
Biogeography - similar species are often found in geographically close but ecologically
different regions, suggesting a graphic common ancestry.
Fossil Records or Paleontology - fossilized organisms are found in specific layers of rock,
and the sequence of these layers reflects the chronological order of species over time.
Molecular Biology - species with a more recent common ancestor tend to have more similar
DNA sequences.
Structures
Homologous Structures - structures with a common evolutionary origin but may have
different functions
Analogous Structures - structures with similar functions but different evolutionary origins
 Vestigial structures - structures that exist in organisms that have no known function which
are believed to be remaining parts from ancestor
Embryology - similarities in the early stages of development among different species suggest
common ancestry
Mechanisms of evolution:
Artificial Selection - mechanism of evolution where humans consciously select for or against
particular features in organisms.
Natural Selection - mechanism of evolution where individuals with heritable traits that favor
survival and reproduction tend to leave more offspring
Types of Natural Selection
Stabilizing - favors the intermediate variants in a population and acts against extreme
phenotypes at both ends
Disruptive - favors the extreme variants of a trait over the intermediate variants
Directional - favors one extreme variant of a trait over the other, leading to a shift in the mean
of the population.
Genetic Drift - evolutionary mechanism where allele frequencies in a population change over
generations due to chance events.
Types of Genetic Drift:
Bottleneck effect - occurs when a sudden sharp decline in the population
Founder Effect - there is a loss of genetic variation due to migration of a small subgroup in the
population
Mutation - random changes in an organism’s genetic makeup, resulting in new alleles and
contributing to genetic variation in a population.
Recombination - mechanism in evolution that introduces genetic variation into populations.
This process naturally occurs during the crossing over stage in meiosis.
GROWTH AND DEVELOPMENT
o Increase in size and complexity respectively

RESPONSE TO STIMULI
 Ability to respond to stimulus
 Irritability
 Stimulus - causes to organism to react.
 Response - reaction.
• tAxis-directional movement of Animals as a response to a stimulus.
• troPism - directional response of Plants toward (positive) or away (negative) from an
environmental stimulus
 Types of Stimulus - Response of Organism
 Phototropism/Phototaxis Growth response to light

Geotropism/Geotaxis Response to gravity

Thigmotropism/Thigmotaxis Response to touch

Chemotropism/Chemotaxis Response to chemical stimulus

Hydrotropism/Hydrotaxis Response to water or soil moisture

Cryotropism/Cryotaxis Growth response to cold

Galvanotropism/Galvanotaxis Response to electricity

Rheotropism/Rheotaxis Response to air or water current

Chromotropism/Chromotaxis Response to color

REPRODUCTION
o Process by which living organisms produce offspring

Sexual Reproduction - Involves sex cells (fertilization). Egg cell and a sperm cell combine to
produce offspring. Results in genetic variation
Types of Fertilization:
 In vitro fertilization (IVF) - medical procedure where an egg is fertilized with sperm outside the
body. (Test tube babies)
 In vivo fertilization - natural internal fertilization where the sperm meets and fuses with the egg
inside the female’s body, typically within the fallopian tubes
 Internal fertilization - occurs inside the female’s body, where the male’s sperm fuses with the
female’s egg
Three ways of Internal fertilization:
o Oviparity: Offspring develop in eggs outside the mother’s body.
o Ovoviviparity: Offspring develop in eggs that are retained within the mother’s body until
they are ready to hatch.
o Viviparity: Offspring develop inside the mother and gain nutrients directly from her
 External fertilization - happens outside the female’s body, commonly in water, where eggs and
sperm are released and meet in the external environment
Asexual Reproduction - Does not utilize gametes. Only single parent. Identical to parent (clone)
Types of Asexual Reproduction:
 Budding - outgrowth or bud from parents (e.g. hydra)
 Binary Fission - living organism splits into two
 Fragmentation - breaking of the parent body or cell into many parts (e.g. planaria)
 Regeneration - ability to regrow its lost part
  Parthenogenesis - an egg develops into a complete individual without being fertilized (e.g.
bees)

Concept of Life
What is Life?
Life
o The culmination of all organism 'physiological activities. Sometimes, it is an energetic force that
can express all the various domains of action.
Living Things
o are things that possess life and all its inherent characteristics are called biological processes.

Characteristics of Living Things

 Living things have any an orderly structure
 Living things are organized into basic unit of life called cells.
 Living things use energy
 Living things are adoptable
 Living things can develop
 Living things can reproduce.
 Living things are coded by genes
 Living things evolve and adapt to their environment

Origin of Life
There are several attempts have been made from time to time to explain the origin of the life
on Earth. There are possibilities that have been either supported or refuted by many scientist
Special Creation
o Also known as Divine Creation
o Life may have been placed on Earth by supernatural/divine forces.
o All the different forms of live created by God.
o In Hindu Concept: Lord Brahma – created the living world in one stroke.
o In Christian and Islamic belief – God created this universe, plants, animals, and human beings
in about six days.
o It has no scientific basis.

Abiogenesis
o Life aroused from non-living matter.

Oparin-Haldane Hypothesis
• During the 1920’s, scientist Aleksandr Oparin and John Haldane independently proposed
that the Earth’s primitive atmosphere was conducive for the creation of organic molecules.
• There was gradual chemical evolution; inorganic molecules reacted with an external energy to
form building blocks; life formed in the primordial soup.
 Miller-Urey Experiment
• The most remarkable experiment in testing the origin of life theories in the Miller-Urey
Experiment
• In 1953, scientist Stanley L. Miller and Harold C. Urey attempted to simulate Earth’s primitive
atmosphere to see what organic molecules would have been producing then.
• It showed that organic molecules could be produced under reducing condition.
Biogenesis
o Life arises from pre-existing life.
o Contested abiogenesis
o Redis and Pasteur’s experiment supported biogenesis and disproved abiogenesis.
o Spontaneous Origin - Also known as the biogeochemical theory
o Refers to the phenomenon that life evolved from in organic and inanimate matter.

Panspermia
o Life may have been seeded by life-forms from another planet
o It suggests that life may have been carried to Earth by beings of extraterrestrial origin.
o Proposed by Richter in 1865 and supported by Arrhenius.

Parts of Cell and its Functions

Cell
o is the smallest unit that is capable of performing life functions.
o The first cell was observed and named by Robert Hooke in 1665 from a sliced of cork

2 major types of living organism

 Prokaryotic cells – Unicellular cell e.g. Bacteria
 Eukaryotic cells – Multicellular cell e.g. Animal, plants
Cell Theory
o All living organism are composed of cell. The Cell Theory developed with the advent of
technology.
Scientist proposed Cell Theory.
 Theodor Schwann (1810-1822) - Cells are the basic units of structure and function in all living
things.
 Matthias Schleiden (1804-1881) - All living things are made up of cells.
 Rudolf Virchow (1821-1902) - All cells come from preexisting cells through cell division.

2 types of cell under Eukaryotic Cell

 Animal Cell - is the smallest biological unit of life found in animals.
 Plant Cell - Plant cells are the building blocks of all plants.
Three Section of the Cell
o All cells take in food, rid waste, reproduction

3 main section
1. Plasma membrane/ Cell membrane
2. Nucleus
3. Cytoplasm
Cytoplasm
o Jelly-like materials inside of the cell.
o Most organelles float within
- Nucleus
- Ribosomes
- Vacuoles
- Mitochondria
- Chloroplast
- Endoplasmic Reticulum
- Golgi Body
- Lysosomes
o Job: Help to facilitate chemical reaction dissolve solutes (Carbohydrates and proteins are
common solutes in the cytoplasm) and move materials around.
o Also add support to the cell through pressure inside.

Plasma Membranes
o Also known as Cell membrane
o Composition: Bilayer of Lipids and Proteins
o Job: Allow materials to enter and exit.
o Small molecules like water and oxygen like this can simply pass through lipid bilayer.
o However, larger molecules like glucose have to pass through these protein channel.
o Semi-Permeable: only specific materials may enter pores and protein channels.
o Also known as selectively permeable
o Meaning that it doesn’t allow everything in and out, it only allows certain specific molecules.

Nucleus
o Job: Controls cell activity also known the brain or headquarters of the cell.
o Contains DNA

Inside:
1. Chromatin
o long twisted strand of DNA
o DNA – is the genetic instructions/information and the blueprint on how to make proteins.
o Chromatin will be sending out information to make proteins.
o Proteins do a lot of work vast. Majority of the work inside cell performed by proteins.
2. Nucleolus
o Make ribosomes
Endoplasmic Reticulum
Types of Endoplasmic Reticulum
1. Rough ER
2. Smooth ER
Rough ER
o Called rough is just because covered in ribosomes
o Receives ribosomes from nucleus
o Job: has a tunnel system that transport protein making ribosomes.
o Rough ER will transport the ribosomes and ribosomes will making a protein.

Smooth ER
o Has no ribosomes
o Makes lipid/fats and break down toxins.

Ribosomes
o Created by Nucleolus inside the nucleus
o Transported the ribosomes to rough ER
o It will proceed to their duty and function is to make proteins.
o Ribosomes gathered amino acid which the building blocks of Protein.
o Job: is to gathered and build amino acid to make a larger protein chain.

Golgi Body
o Also known as Golgi Apparatus
o It received proteins that ribosomes made modify them, sort them and package them so they
can be exported from the cell.
o Put the proteins into a protective little enveloped known as a vesicle.

Mitochondria
o Create ATP Adenosine Triphosphate (energy molecule) in a process called cellular respiration.
o It serves as a battery of the cell.

Lysosomes
o Contains digestive enzymes.
o It breaks down food.
o Kill pathogens (viruses that can affect to the cell)
o Autolysis: Destroy dying cell or aging cells.

Cell wall
o The outermost layer of plants, fungi and bacteria cells.
o Adds support for growth
o Made of tough cellulose
o Hard to digest.
Chloroplast
o Perform photosynthesis
o Chlorophyll molecules absorb sunlight and convert water and CO2 into sugars.
o Photosynthesis absorbs sunlight, absorb carbon dioxide, absorbs water turn those into
oxygen and glucose.
o Does photosynthesis use three ingredients: water, carbon dioxide, sunlight will release two
products, oxygen and sugar (Glucose).
Endosymbiosis Theory
o Were once free-living organism that became parts of modern cells
o Evidences: Own DNA and Ribosomes, Make Proteins, and Replicate.

Vacuole
o It stores food, water, waste, color pigments.
o In plant Cells: It has a Large central vacuole
o In animals Cells: Scattered smaller vacuoles.

Centrioles
o Its function is connected to cell reproduction.
o A tiny organ that help the cell division.

HOW ORGANISMS OBTAIN AND UTILIZE ENERGY

Modes of Nutrition
 Autotrophs - are known as producers because they are able to make their own food from raw
materials and energy. Examples include plants, algae, and some types of bacteria.
 Heterotrophs - known as consumers because they consume producers or other consumers.
Dogs, birds, fish, and humans are all examples of heterotrophs.
Photosynthesis
o Is the entire process of capturing light energy to produce food. Plants, algae, and other
chlorophyll – bearing organism capture light energy and use it to procedure energy-rich
organic molecules from carbon dioxide.
 Photosynthesis is summarized in the following equation.
6CO2 + 6H2O + light energy --------------- C6H12O6 + 6O2
Carbon Dioxide Water Chlorophyll Sugar (Glucose) Oxygen

1. Light dependent
- This reaction can take place only in the presence of light (Solar Energy).
- Light dependent reactions are also known as energy-capturing reaction, they capture solar
energy and store it in molecules that will supply the energy necessary for the next reaction
occur.
2. Light Independent
- They do not require light in order to take place.
- These reactions convert short-term energy store (ATP) to long term energy storage (Sugar)

Cellular Respiration
o Is essential opposite of Photosynthesis
o Breaking down food (glucose) to produce ENERGY (ATP)

C6H12O6 + 6O2 --------------- 6CO2 + 6H2O + Energy (ATP)

PERPETUATION OF LIFE
Reproduction
o Is the process by which all living organism produce one of their kinds to ensure the survival of
the species.
o The perpetuation of life is dependent on the process of reproduction.

Plant Reproduction
o The Reproductive organ of plants is the flower

Sexual Reproduction in Plants

 Pollination
- Is the transfer of pollen grains from anther to the stigma of a flower.
- If the transfer involves the same flower, it is termed self-pollination.
- If the transfer is from one flower of one plant to another plant, it is called cross-pollination.
- Agents: Insect, wind, water, birds, and humans.
 Fertilization
- The pollen grain that lands on the stigma develops a pollen tube that grows down through
the style and into the ovary where the ovule is located.
- the sperm travels down the pollen tube and fertilized the egg cell inside the ovule.
- The fertilized egg called zygote develops into embryo.
- The ovule becomes seed. The ovary swells up and ripen to form a fruit. Inside the seeds
plant embryo is located.
Asexual Reproduction in Plants
o Is a kind of reproduction that creates genetically identical offspring. The offspring that arise
from asexual reproduction can be considered clones.
o In most plants, asexual reproduction is an advantageous adaptation.
o A strawberry plant can reproduce by sending out horizontal stems called Runners.
o Along the runners, new roots and shoots develop at every node.
o The type of reproduction in plants from its vegetative parts such as stem, roots, and leaves is
called Vegetative Reproduction.
o Vegetative Propagation - It is a method wherein new plants are obtained from the parts of old
plants like stems, roots and leaves without use of any reproductive parts.
o Examples: New plants grow from the eyes of potatoes, cloves of garlic bulbs and runners of
Bermuda grass, tubers of potatoes, and rhizomes of ginger.

Methods of Vegetative Reproduction

 Cutting
- wherein pieces of stem or roots are cut and planted in soil.
- Cassava grows from cutting.
 Budding
- propagation method that involves inserting a bud from a desirable plant into
the bark of a compatible rootstock to create a new plant.
 Grafting
- a vegetative propagation technique that involves joining two plants together so that they
grow as a single plant.
 Marcotting
- a plant propagation technique that involves growing a new plant from a branch that's still
attached to the parent plant.

Animal Reproduction
o Sexual Reproduction in Animals

Animal Sexual Reproduction

o a process in which two animals exchange genetic information to produce offspring with a
unique combination of genes.
3 Parts of Sexual Reproduction
1. Pre-fertilization
2. Fertilization
3. Post-fertilization
Pre-fertilization
- The process that occurs before the actual fertilization
Fertilization
 - A multi-step process that is complete in 24 hours.
- The sperm from a male meets an ovum from male and forms a zygote.
Types of Fertilization
• Internal Fertilization – fertilization occurs inside the female body of an
organism.
• External Fertilization – fertilization that occurs outside the body of an organism.
Post-fertilization
- After fertilization, involving embryogenesis (the process by which an embryo develops)

THREE METHODS OF FERTILIZATION

1. Oviparity
2. Viviparity
3. Ovoviviparity
Oviparity
- A reproductive method in which animals lay eggs instead of giving birth to live young.
Viviparity
- Producing living young instead of eggs from within the body in the manner of nearly all
mammals, many reptiles, and a few fishes.
Ovoviviparity
- is a reproductive method where embryos develop inside eggs that remain in the
mother's body until they hatch.
- This process is similar to live birth and is considered a "bridging" form of reproduction
between egg-laying and live-bearing.

Animal Asexual Reproduction

o a process where a single parent organism divides to produce offspring that are genetically
identical to the parent.
Types of Animal Asexual Reproduction
 Spore Formation
 Budding
 Fission
 Fragmentation
 Regeneration
 Vegetative propagation

Spore Formation
 - Is a type of asexual reproduction where organisms reproduce by forming spore.
- Spores are the single called-celled reproduction unit of non flowering plants, bacteria,
fungi, and algae.
Budding
- Involves the splitting of new individuals from the existing ones by forming small
projections, called bud’s, from the parents body.
- A new organism is formed from an outgrowth from the parent
Fission
- An organism grows and duplicates its genetic material then divided in to two.

Fragmentation
- It happens when new organism grows from a fragment of the plant.
Regeneration
- It occurs when a body part is detached from the parent.
- This part grows and develops into a completely new individual.