Unit 1: Biodiversity
Lesson 10: Plants & Animals
PLANT KINGDOM:
Importance of Plants:
 can survive in many climates (desserts to arctic)
 plants are producers of food therefore, wherever there are plants, rich diversity of terrestrial
life will follow
 support food webs
 provide other organisms places to live
 humans use for resources -- food, medicine, clothing, wood, paper products etc.
Classification & Phylogeny:
Plants are thought to evolve from charophytes which is a group of green algae belonging to the
kingdom Protista. Plants and green algae both contain chlorophyll a and b (green pigments used in
photosynthesis). Both plants and green algae cells make cell plants at the end of mitosis before
cytokinesis, have cellulose in their cell walls, and store excess food as starch.
Key Characteristics:
 multicellular and eukaryotic
 perform photosynthesis
 sessile (cannot move from place to place)
 autotrophic
 mostly terrestrial (the aquatic plants are mostly fresh water)
 reproduce sexually and asexually
ANIMAL KINGDOM:
Importance of Animals:
 the more we learn about the biology of animals, the more we learn about ourselves (ex: origin of
human diseases, how to keep ourselves healthy etc)
 food source -- directly eat animals or rely on them for pollination of plants
 maintain healthy ecosystems
 friends - domesticated pets
 throughout history and culture animals have been revered as symbols of power, beauty,
freedom, peace etc.
Classification & Phylogeny:
The common ancestor of all animals was likely a colonial, flagellated protist. Biologists
hypothesize that a spherical arrangement of cells in a colony might have become indented, forming a
hollow cavity. This would have helped the organism capture and digest food. This same basic
arrangement and indenting process can be still observed in the embryonic development of animals
today. Some cells in the colony may also have become specialized for feeding. This double-layered
arrangement of cells with a lining of specialized digestive cells is very similar to that of sponges, the
simplest of all modern animals.
A key innovation among animals was the development of
nerve
specialized cells. These allow movement and the ability to sense changes in the environment. Animals in
the porifera (sponges) are the only ones that do not have this key animal feature.
Another major division among animal phyla is between those with radial symmetry (symmetry
around a central axis) and those with bilateral symmetry (symmetry around a midline).
Animals with bilateral symmetry are further divided into two major branches. The protostomes and
deuterostomes are distinguished by different patterns of embryonic development. Humans belong to
the deuterostomes phylum Chordata. The Chordata are almost entirely vertebrates - animals with a
dorsal backbone or notochord, including fish, amphibians, reptiles, birds and mammals. All other animals
are referred to as invertebrates.
Protostome: an animal with bilateral symmetry; during embryonic development, the mouth forms before the anus.
Deuterostome: an animal with bilateral symmetry; during embryonic development, the anus forms before the
mouth.
Vertebrate: an animal with a backbone or notochord
Notochord: a flexible rod found in some chorodates; in most modern chordates it is replaced by vertebrae during
embryonic development
Invertebrate: an animal that does not have a backbone; the great majority of animal species are invertebrates
Key Characteristics:
 eukaryotic and multicellular
 all are heterotrophic
 use oxygen for aerobic respiration
 no cell wall
 their cell membranes are in direct contact with each other
 mostly reproduce sexually
 can be terrestrial or aquatic