SBI 3UI Biology - Unit 1 Diversity of Living Things (Chapter 1)

The 10 Themes of Biology

The 10 Themes of Biology

• Biological Systems

• The Cellular Basis for Life

• Form and Function

• Reproduction and Inheritance

• Interaction with the Environment

• Energy and Life

• Regulation

• Adaptation and Evolution

• Biology and Society

• Scientific Inquiry

Biological Systems

• Organisms are living systems made up of many individual parts

• Ecosystems are complex biological systems

The Cellular Basis of Life

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

• Multicellular organisms have cells that are specialized for different functions

Form and Function

• How something works is related to its function

  • Eg. The aerodynamic shape of a birds wing, and the structure of the bird’s bones allows it to fly

Reproduction and Inheritance

• Offspring inherit units of information called genes from their parents. Genes are responsible for family inheritance

Interaction with the Environment

• All organisms must interact with, respond to and affect the environment

Energy and Life

• In order for organisms to do any kind of work (moving, growing, reproducing) they need a source of energy

  • Producers vs Consumers

  • Energy flow through ecosystems

Regulation

• Organisms can, to varying degrees, regulate their internal conditions

  • Thermoregulation (internal body temperature in mammals)

  • Osmoregulation (maintaining water balance eg. Kidneys in mammals)

Adaptation and Evolution

• An adaptation is an inherited trait that helps an organism’s ability to survive and reproduce in its particular environment

• Evolution refers to the idea that all species are descendants of accident species that were different from modern-day series

Biology and Society

• Modern biology has changed human lives and continues to do so

• Biotechnology

• Medical Research

• Agriculture

• Conversation

Scientific Inquiry

• Scientific inquiry involves asking questions about nature and then using observations or experiments to find possible answers to those questions

Extinct

The last members of the population on the planet have died

Main Factors That Threaten Biodiversity

• Habitat Loss (greatest threat)

• Invasive Species

• Pollution

• Overexploitation

• Climate Change

Habitat Fragmentation

Habitat fragmentation alters small areas within a large region, creating a patchwork of altered and original habitats

Invasive Species

Non-native species that harm ecosystems they are introduced to

Overexploitation

The unsustainable use of resources

Synergistic Effects

The impacts of several human activities combined

Effects of Climate Change on Biodiversity

• Disease Outbreaks

• Plant Migration

• Animal Migration

• Extreme Weather

• Increased CO2 Levels

• Decreased Water Availability and Quality

Two Goals of Conservation Biology

1. Finding solutions

2. Carrying them out

Ex-situ Conservation

Protecting species by removing them from their natural habitats

In-situ Conservation

Protecting species in their natural habitats

Genetic Diversity

The sum of all the different forms of genes present in a particular species

Species Diversity

The variety of species and relative abundance of species in a given area

Ecosystem Diversity

A diverse range of habitats and the relationships that connect them

Valuing Biodiversity

All ecosystems on Earth are healthier when there is increased biodiversity on all levels

Reason to value biodiversity:

• Insects, bats, birds and other animals pollinate flowering plants and crops

• Mirco-organisms make nutrients available and break down toxic substances in water and soil

• Ecosystems cycle carbon, nitrogen, and oxygen

• Ecosystems clean air, purify water, control erosion, prevent floods and modify climate

Importance of Scientific Names

Scientific names for species are important because an organism can have many common names or a common name can often refer to many different kinda of organisms.

• Needed to develop a scientific name for each species that could be used universally

Carolus Linnaeus

Developed the most commonly used system to categorize organisms, which is still in use today

• The Father of Taxonomy

Taxonomy

The science of naming, identifying and classifying species

• Provides a method to allow organisms to be identified

• Based on morphology: the study of form and structure or organisms, uses the physical characteristics to organize organisms

• Follows well-defined rules that describe how to properly name and classify any organism

• Represents the relationships among organisms

• Identifies organisms based on their species

Biological Species Concept

a species consists of members of a group that share a gene pool therefore they can interbreed and produce fertile offspring

This definition of species doesn’t work for all organisms on Earth such as:

• those who reproduce asexually, including all archaea, bacteria, many protists, plant and even some animals

• those that have become extinct

• those that have not been observed to reproduce, cannot successfully mate or do not get the opportunity to

Hybridization

Hybrids rarely occur in nature since the infertile offspring are a genetic deadend - the genes of the parents cannot be passed on. Mating is very energy intensive so the payoff is passing on your traits

Mule

• From a male donkey (jack) and a female horse (mare)

• Great variety, generally stronger and more sure-footed than donkeys, easier to work than horses

• 63 chromosomes, infertile, not a species (odd # of chromosomes, cannot reproduce)

Hinney

• From a male horse (stallion) and a female donkey (hinnet)

• Lower success rate so generally not bred

• 63 chromosomes, infertile, not a species

Prokaryote

A single-celled organism that lacks a membrane-enclosed nucleus and membrane-enclosed organelles (ex. bacteria)

Eukaryote

An organism made up of one or more cells that have both a membrane-enclosed nucleus and membrane-enclosed organelles (ex. plant and animal cells)

Genetic Material (Characteristics of Prokaryotes)

• DNA is not coated with protein

• Often occurs in strands or floats freely in cytoplasm

Cell Division (Characteristics of Prokaryotes)

• Fission or budding

Sexual Recombination (Characteristics of Prokaryotes)

• Transfer of genes from donor to recipient

Tissue Development (Characteristics of Prokaryotes)

• None

Respiration (Characteristics of Prokaryotes)

• Some require oxygen and some do not

Size (Characteristics of Prokaryotes)

• Microscopic (1 - 10 pm)

Energy Production (Characteristics of Prokaryotes)

• Free-floating enzymes in cytoplasm

Flagella (Characteristics of Prokaryotes)

• Very simple

Genetic Material (Characteristics of Eukaryotes)

• A nucleus bound by a membrane contains chromosomes made of DNA and proteins

Cell Division (Characteristics of Eukaryotes)

Splits into two genetically identical cells

Sexual Recombination (Characteristics of Eukaryotes)

• Often a male and female participate in fertilization

Tissue Development (Characteristics of Eukaryotes)

• Sometimes

Respiration (Characteristics of Eukaryotes)

• Almost all require oxygen

Size (Characteristics of Eukaryotes)

• Most are large cell (10 - 100 pm)

• Some are micro-organisms

Energy Production (Characteristics of Eukaryotes)

• Enzymes for energy production are located in mitochondria or chloroplasts

Flagella (Characteristics of Eukaryotes)

Complex

Cell Type (Eubacteria)

Prokaryote

Cell Structures (Eubacteria)

Cell walls with peptidoglycan (a coat of sugars)

Number of Cells (Eubacteria)

Unicellular

Mode of Nutrition (Eubacteria)

Makes its own food or eat other organisms

Cell Type (Archaebacteria)

Prokaryote

Cell Structures (Archaebacteria)

Cell walls without peptidoglycan

Number of Cells (Archaebacteria)

Unicellular

Mode of Nutrition (Archaebacteria)

Makes its own food or eats other organisms

Cell Type (Protista)

Eukaryote

Cell Structures (Protista)

• Cell walls of cellulose in some

• Some have chloroplasts

Number of Cells (Protista)

• Most unicellular

• Some colonial

• Some multicellular

Mode of Nutrition (Protista)

Makes its own food or eats other organisms

Cell Type (Fungi)

Eukaryote

Cell Structures (Fungi)

Cell walls of chitin

Number of Cells (Fungi)

• Most multicellular

• Some unicellular

Mode of Nutrition (Fungi)

Breaks down organic matter into nutrients

Cell Type (Plantae)

Eukaryote

Cell Structures (Plantae)

Cell walls of cellulose, chloroplasts

Number of Cells (Plantae)

• Most multicellular

• Some unicellular

Mode of Nutrition (Plantae)

Makes its own food

Cell Type (Animalia)

Eukaryote

Cell Structures (Animalia)

No cell walls or chloroplasts

Number of Cells (Animalia)

Multicellular

Mode of Nutrition (Animalia)

Eats other organisms

Dichotomous Key

A tool used to identify living organisms

• The key uses a series of questions or statements regarding the features of an organisms and each question asks users to choose between two possible characteristics the organism may have

Charles Darwin’s Theory of Evolution

This theory states that all living things are descended from a common ancestor

• Was described in “The Origin of Species”

Phylogeny

The science that deals with evolutionary relationships between and among species

Cladistics

The classification system based on phylogeny

• Based on the idea that each group of related species has one common ancestor and organisms keep some of the ancestral traits (primitive) and gain some unique characteristics (derived)

Phylogenetic Tree

Often used to illustrate the evolutionary relationships among various species

• Most of the evidence for these relationships is based on similarities and differences in physical and genetic characteristics

• In a phylogenetic tree, species are grouped into clades

Clade

A taxonomic group that includes a single ancestor species and all its descendants

• Root/Base = oldest ancestral species

• Upper ends of branches = present-day descendants

• Nodes (where the branches fork) = points in the past at which an ancestral species splits into two new species

• Small if species share a very recent common ancestor

• Large if species share a distant common ancestor

• Organisms that share a more recent common ancestor will have fewer differences in the phylogeny

4 Things Taxonomists Use to Determine Relatedness

1. Evidence from Anatomy - Evidence in bone structure or anatomy, using fossilized evidence to show relatedness

2) Evidence from Development - Comparisons of early stages of embryological development

3) Evidence from Biochemistry - Comparison of biological molecules (fats, proteins, carbs, nucleic acids) among different species

4) Evidence from DNA - Comparison of DNA sequence and genes

3 Main Domains

1. Bacteria

2. Archaea

3. Eukarya

Domain: Bacteria

Kingdom: Eubacteria

Domain: Archaea

Kingdom: Archaebacteria

Domain: Eukarya

Kingdom: Protista, Fungi, Plantae, Animalia