Great Ideas in Science Lecture 10 - Living Things

1
Great Ideas in Science Lecture 10 - Living Things

• Prof. Robert Hazen
• UNIV-301

2
Every Living thing

1. Can be classified in one scheme
2. Is modular composed of a few simple molecules
3. Is made of cells lifes chemical factories
4. Uses the same genetic code
5. Evolved from a first cell by natural selection
6. Lives in ecosystems of many interdependent
   organisms

3
Ways of Thinking About Living Things

• Biosphere
• Ecosystem
• Community
• Population
• Organism
• Anatomy physiology
• Cellular
• Molecular

4
What is Life?

• Encapsulation All life is separated from the
  environment by a membrane.
• Metabolism All life obtains energy and atoms
  from the environment.
• Reproduction All life reproduces via genetics.

5
The Characteristics of Life

• High degree of order and complexity
• Part of larger systems of matter and energy
• Life depends on chemical reactions in cells
• Life requires liquid water
• Organisms grow and develop
• Regulate energy use
• Share same genetic code, code is heritable
• All living things are descended from a common
  ancestor

6
Great Idea Living things use many different
strategies to deal with the problems of acquiring
and using matter and energy.

• Linnaean classification
• Hierarchy
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

7
Why is Taxonomy Important?

• Think about how to describe a tree.
• Names are essential for accurate communications
• But taxonomy can be rather
• arbitrary
• Lumpers versus splitters
• Local variations in species

8
Why is Taxonomy Important?
Dracorex (top left) and Stygimoloch (top right),
as growth stages of Pachycephalosaurus (bottom).
9
Why is Taxonomy Important?
C
A
B
10
Classifying Life

• Kingdoms
• Monera
• Protista
• Fungi
• Plants
• Animals

11
Taxonomy of Animals
12
Classifying Human Beings

• Kingdom Animals
• Phylum Chordates
• Subphylum vertebrates
• Class Mammals
• Order Primates
• Family Hominid
• Genus Homo
• Species sapiens

13
A New ViewThree Domains of Life

• Bacteria
• Archaea
• Eukarya

14
Implications of Linnaean Classification

• You can use genetic material.
• Similarities depend on time and change.
• Classification results from real events.

Nothing in biology makes sense except in the
light of evolution.
15
Strategies of Fungi

• Growth
• Filaments
• Decomposers
• Structure
• Mass of filaments
• Many forms
• Reproduction
• Break filaments
• Spores (usually asexual)
• Lichens
• Fungi Algae
• Two interdependent species

16
The Simplest Plants

• Phylum Bryophytes
• Structure
• No roots
• Photosynthetic
• Reproduction
• Sexual
• Asexual

17
Vascular Plants

• Phylum vascular plants
• Structure
• Roots, stems, leaves
• Control water loss
• Reproduction
• Spore fertilized egg
• Cone holds egg or sperm
• Seed egg plus nutrients
• Pollen sperm
• Strategies
• Seedless (Ferns - spores)
• Seeds but no flowers (Gymnosperms - cones)
• Seeds and flowers (Angiosperms)

18
Angiosperms
19
Invertebrates

• No backbone
• Most diverse animals
• Arthropods
• 70 of known animal species
• Structure
• Exoskeleton
• Jointed legs

20
The Molecules of Life

• All life is modular composed of a few simple
  molecules.

21
Key Ideas about the molecules of life

• Based on Carbon (Organic chemistry)
• Six main elements (CHNOPS)
• Modular built from simple units
• Molecular shapes determine their function

22
Nutrition Facts

• Energy

• Lipids
• Sugars
• Amino acids

23
Carbohydrates (sugars)
Carbon Hydrogen Oxygen
24
Cellulose and Starch
25
Lipids
26
Saturated and Unsaturated Lipids
27
Amino Acids

• Amino group
• Carboxyl group
• Side-group (20 different things)

28
Protein sequence of amino acids

• Primary chain of amino acids
• Secondary folding of chain
• Tertiary
• Quaternary

29
Proteins

• Structural role

30
Proteins Enzymes
31
Dietary Amino Acids