Introduction to Biology

Biology

Definition: Biology is the study of living organisms, their structure, function, growth, origin, evolution, and distribution.
Branches of Biology:
- Botany: Study of plants.
- Zoology: Study of animals.
- Microbiology: Study of microorganisms.
- Genetics: Study of heredity and variation in organisms.
- Ecology: Study of interactions between organisms and their environment.
Cell Theory:
- All living organisms are composed of cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Types of Cells:
- Prokaryotic Cells: No nucleus or membrane-bound organelles (e.g., bacteria).
- Eukaryotic Cells: Have a nucleus and membrane-bound organelles (e.g., plants, animals, fungi).
Genetic Material:
- DNA: Carries genetic information; composed of nucleotides (A, T, C, G).
- RNA: Involved in protein synthesis; types include mRNA, tRNA, and rRNA.
Evolution:
- Theory of natural selection proposed by Charles Darwin.
- Evolution explains the diversity of life and adaptation to environments.
Homeostasis: The ability of an organism to maintain a stable internal environment despite changes in external conditions.
Metabolism:
- Anabolism: Building up of molecules (e.g., synthesis of proteins).
- Catabolism: Breaking down of molecules (e.g., cellular respiration).
Reproduction:
- Asexual Reproduction: Offspring arise from a single organism (e.g., binary fission).
- Sexual Reproduction: Involves the combination of genetic material from two parents.
Ecological Levels:
- Organism: Individual living entity.
- Population: Group of individuals of the same species.
- Community: Different populations living together.
- Ecosystem: Community plus the physical environment.
- Biosphere: Global sum of all ecosystems.
Human Biology:
- Anatomy: Structure of the human body.
- Physiology: Study of body functions.
- Major systems: Circulatory, respiratory, digestive, nervous, muscular, and skeletal.
Current Topics in Biology:
- Biotechnology: Genetic engineering and CRISPR technology.
- Conservation Biology: Protecting biodiversity and ecosystems.
- Neuroscience: Study of the nervous system and brain functions.

Biology Overview

Biology examines living organisms, including their structure, function, growth, evolution, and distribution.

Branches of Biology

Botany studies plant life.
Zoology focuses on animal species.
Microbiology investigates microorganisms, including bacteria and viruses.
Genetics explores heredity, gene variation, and inheritance patterns.
Ecology analyzes interactions between organisms and their environments.

Cell Theory

All living organisms are formed from cells.
Cells serve as the fundamental unit of life.
New cells originate from existing cells.

Types of Cells

Prokaryotic Cells lack a nucleus and membrane-bound organelles; examples include bacteria.
Eukaryotic Cells possess a nucleus and membrane-bound organelles; examples include plant and animal cells.

Genetic Material

DNA is the blueprint of life, made up of nucleotides adenine (A), thymine (T), cytosine (C), and guanine (G).
RNA plays a key role in protein synthesis and encompasses various forms, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).

Evolution

Charles Darwin's theory of natural selection describes how species evolve and adapt to their environments over time.

Homeostasis

Organisms possess the ability to maintain stable internal conditions despite external environmental changes.

Metabolism

Anabolism refers to the synthesis of complex molecules from simpler ones, such as protein creation.
Catabolism involves the breakdown of molecules, exemplified by cellular respiration.

Reproduction

Asexual Reproduction: Single-parent reproduction, e.g., binary fission in bacteria.
Sexual Reproduction: Combines genetic material from two parents resulting in diverse offspring.

Ecological Levels

Organism: The smallest unit; an individual living entity.
Population: A group of the same species living in a specified area.
Community: Various populations coexisting in a shared environment.
Ecosystem: Encompasses a community and its physical surroundings.
Biosphere: Represents the entirety of Earth's ecosystems.

Human Biology

Anatomy examines human body structures.
Physiology focuses on body function and processes.
Major human systems include: circulatory, respiratory, digestive, nervous, muscular, and skeletal systems.

Current Topics in Biology

Biotechnology involves genetic engineering techniques, such as CRISPR.
Conservation Biology emphasizes the protection of biodiversity and ecosystems.
Neuroscience studies the structure and function of the nervous system and brain.