Biodiversity 1-3

Characteristics of life

CHARRM G

C-Cellular organization

H-Homeostasis

A- Adaptation

R- Reproduction

R- Response to stimuli

M- Metabolism

G- Growth

Homeostasis

Maintaining stable internal conditions despite changes in external environment. For example: temperature, blood glucose, fluid levels

Essential for survival and uses negative feedback loops to prevent harmful deviations

Metabolism

The sum of all chemical reactions.

Catabolism: Breaking down molecules (C for cellular respiration)

Anabolism: Building molecules (Photosynthesis)

Cellular Organization

Organelles → cells → tissues → organs → organ systems → organism

Growth and development

Living organisms grow and develop based on genetic instructions encoded in DNA

For example: fertilized egg develops into multicellular organism through cell division and differentiation

Adaptation

Populations and organism evolve over generations, developing traits that increases fitness (survival and reproduction).

For example: antibiotic resistant bacteria, or camouflage in animals

Reproduction

Living organisms can reproduce either sexual or asexual to pass on genetic information.

Crossing over in sexual reproduction (exchange of DNA segments across homologous chromosomes)

Difference between Adaptation and Response to stimuli

Adaptation: Over many generations (development of fur in cold climates)

Response: Immediate (pulling hand away from heat)

Ecosystem biodiversity

Variety of ecosystems, habitat, or ecological processes in a region (forests, wetlands, etc.)

Genetic diversity

Variation in genes within a species or population (different dog breeds, variation in crops resistance to disease, etc.)

Species diversity

The number and relative abundance of different species in an ecosystem

Important requirements for classification of organisms

1. Consistent

2. Universal

3. Based on observable and measurable traits

Taxonomy

Taxonomy is the science of naming, identifying, and classifying organisms based on SHARED characteristics.

Purpose of taxonomy is

1. To organize biodiversity

2. To identify organisms

3. To understand relationships between organisms

Aristotle System (4th Century BC)

Organisms were grouped based on habitat:

1. Water

2. Land

3. Air

Use-based classification

Organisms based on how usefulness to humans

1. Useful

2. Harmful

3. Neutral

Morphological Classification (1600s)

JOHN RAY proposed organisms were grouped based on physical characteristics, including structure and form.

John Ray

Introduced the concept of species based on shared ancestry, introduced the distinction between monocotyledons and dicotyledons and organized large scale, systematic catalogues.

Issues with John ray’s Classification system

His morphological classification system was limited because organisms may look similair but be genetically different, or look different but be closely related.

Impact of the microscope

With the invention of the microscope, John Ray’s classification system could no longer work due to microscopic organism. Classification needed to become more detailed and systematic.

Linnaeus

Developed hierarchical classification system based on morphology and universal naming system that we use today.

Binomial Nomencalture

Each organism is given a two part scientific name

Genus: A Group of closely related organisms (Capitalized)

Species: A specific organism within that group (lowercase)

Why use Latin?

Latin is universal

Dead language so does not change over time

Ensures consistency in scientific communication GLOBALLY

Classification Hierarchy

As you move down hierarchy: Groups become more specific and organisms become similar

1. Kingdom

2. Phylum

3. Class

4. Order

5. Family

6. Genus

7. Species

Dichotomous Keys

Tool used to identify organisms using a series of paired contrasting choices

Each step presents two options

Each option leads to a branch

Process continues until organism is identified

Phylogeny

Study of the evolutionary history and relationships among organisms

Phylogenetic trees

Act like a map, showing both relationships and detailed evolutionary history, with branch lengths representing time or genetic change

Carl Woese’s three domain system (19977)

Reorganized tree of life into Bacteria, Archaea, and Eukarya- based on ribosomal (rRNA) analysis. Discovery proved that Archaea was genetically distinct from bacteria and more related to eukaryotes.

Linnaeus’s (Hierarchy) and Woese’s classification became combined in 1990s and early 2000s

3 domains of life

A domain is the largest and most inclusive level of classification based on CELL TYPE and GENETIC MAKEUP

1. Bacteria

2. Archaea

3. Eukarya

Bacteria

1. Prokaryotic

2. Cell walls contain peptidoglycan

3. Extremely diverse

4. Found in almost ALL environments

Archaea

1. Prokaryotic

2. Genetically different from bacteria

3. Found in extremes environments

4. High heat (thermophiles)

5. High salt (halophiles)

Eukarya

1. Eukaryotic cells (contain nucleus and organelles)

2. Includes multiple kingdoms like Protista, Plantae, Fungi, and Animalia

6 kingdoms

1. Animals

2. Fungi (mushroom, mold, yeast)

3. Monerans (Archaea, bacteria)

4. Protista (protozoans, algae)

5. Plants

Cladogram

Show hypothetical relationships based on shared characteristics WITHOUT representing time or genetic distance

Show evolutionary relationships between organisms based on derived characteristics

Clade

Show common ancestors and all of its descendants

Root

Common ancestor

Node

Branch point representing a speciation event leading to 2 new species

Outgroup

Most distant related species in cladogram

Derived characteristics

A trait that appears in recent members of a group but not in ancestors

Ancestral characteristic

A trait that is shared with distant ancestors