Principles of Biology

1
Principles of Biology

• By
• Frank H. Osborne, Ph. D.
• Ecology

2
Definition of Ecology

• Ecology is the science that deals in the
  interrelationships between organisms and their
  environment. The environment contains physical
  factors and living factors.

3
Physical Factors

• The physical environment consists of the soil and
  rocks in the surroundings of the organism. The
  light, heat and water in the surroundings are
  also part of the physical environment.

4
Living Factors

• The living environment consists of all plants and
  animals nearby which interact with the organism.
  This is a community. All of the organisms of the
  same species within the community constitute a
  population.

5
Energy in the Environment
Path of Energy Sun ? Plant ? Insect ? Frog ?
Snake
6
Food Chains

• All energy on the surface of the Earth is derived
  from the Sun. Photosynthesis occurs in the
  primary producers that are green plants.
• Primary consumers eat the plants.
• Predators eat the primary consumers. The
  predators are secondary consumers.
• This constitutes a food chain.

7
Food Chains

• There may be tertiary or quaternary consumers.
• In North America, most food chains end with a
  predatory bird, such as the eagle.

8
Flow of Energy in Food Chains

• Energy in food chains always begins with the Sun.
  Sunlight is absorbed by green plants. The green
  plant uses photosynthesis to trap solar energy
  and convert it to glucose. The glucose molecule
  contains stored chemical energy.

9
Flow of Energy in Food Chains

• The primary consumer eats the green plant and
  gains some of the energy from it. The primary
  consumer is a herbivore because it eats plants.
  Most of the energy of the plant is lost when it
  is eaten.

10
Flow of Energy in Food Chains

• The secondary consumer eats the primary consumer.
  It is a carnivore. The carnivore obtains some
  of the energy stored in the animal it eats but
  most of the stored energy is lost.

11
Flow of Energy in Food Chains

• Thus, energy is lost as the food chain grows
  longer. In order to obtain the maximum amount of
  energy stored by the original producer plant, you
  have to eat the plant directly.

12
Flow of Energy in Food Chains

• Organisms die eventually. Their remains are
  recycled and returned to the environment by decay
  organisms, particularly bacteria and fungi that
  derive energy from dead organic material.

13
Food Webs

• Food webs are more complicated than food chains
  because some consumers may be eaten by several
  predators. This causes branches in food chains.

14
Succession of Plants (1)

• Newly exposed rock will first be colonized by
  lichens.

15
Succession of Plants (2)

• These are joined by small plants like mosses and
  liverworts. After some soil begins to form,
  ferns and grasses move in.

16
Succession of Plants (3)

• More soil forms and then shrubs and pine trees
  begin to grow. The thickness of the soil
  continues to increase.

17
Succession of Plants (4)

• The shrubs and pine trees are replaced by oak
  trees, beech trees and finally maple trees. In
  the temperate forests of the United States, the
  climax vegetation will be maple trees.

18
Succession of Plants (5)

• The sequence from bare rock to mature forest
  takes about 100 years.

19
Ecological Succession

• Early (pioneer) plants - 1. lichens
• - 2. liverworts/mosses
• - 3. ferns
• - 4. grasses
• Intermediate plants - 5. pine trees
• - 6. oak trees
• - 7. beech trees
• Climax forest plants - 8. maple trees

20
Biomes

• A biome is a collection of many communities which
  is characterized by the same form of climax
  vegetation.
• The climax vegetation is a botanical community.
  For example, the northeastern United States is in
  the biome known as the Temperate Deciduous
  Forest. "Deciduous" means that the leaves fall
  off the trees in the autumn.

21
Biomes

• Terrestrial biomes depend on climate. The
  climate changes as you travel toward the North
  Pole. It changes in a similar fashion as you go
  high up into the mountains. Climates similar to
  Tundra and Taiga are found on high mountains.

22
Biomes

• There are six generally recognized terrestrial
  biomes, distinguished by their climate and climax
  vegetation.
• Tundra
• very cold, short growing season, ground is
  permanently frozen (permafrost)
• Taiga
• cold, moderate growing season, predominant plants
  are trees with needles and cones

23
Biomes

• Temperate Deciduous Forest
• moderate climate, long growing season, trees have
  broad leaves which fall off during autumn
• Grassland
• moderate climate but too dry to support trees.
  Best for growing wheat and corn

24
Biomes

• Desert
• very dry with extremes of hot and cold.
  Predominant vegetation is cactus and other plants
  adapted to very dry conditions
• Tropical Rain Forest
• very humid all the time--supports lush vegetation

25
Biomes

• The marine biome includes all of the communities
  that are found in the ocean. The types of living
  things present in a given part of the marine
  biome depend on the water temperature,
  availability of food and nutrients for the sea
  life, and other factors.

26
Material Cycles

• Nature works in cycles. There are a number of
  cycles in the ecosystem that serve to regenerate
  and renew materials for use by living things.

27
Carbon-Hydrogen-Oxygen Cycle

• Photosynthesis by green plants releases oxygen
  into the atmosphere because oxygen is the waste
  product of photosynthesis.
• Living things use oxygen for their respiration
  and release water and carbon dioxide into the
  atmosphere. These materials are then used by the
  plants for more photosynthesis.

28
The CHO Cycle
29
The Nitrogen Cycle

• Nitrates from the soil are absorbed by the green
  plants and are used to make plant proteins.
  Animals make proteins from amino acids derived
  from plant proteins.
• Dead plant and animal tissue is decomposed by
  bacterial action. Other bacteria in the soil
  transform nitrogen products to reduce more soil
  nitrates for plants.

30
The Nitrogen Cycle
31
Relationships Between Organisms

• Between organisms of the same species there can
  be sexual contact, cooperation and social
  organization.
• Between different species, the interactions are
  commensalism, mutualism, parasitism and
  predation. All of these interactions are forms
  of symbiosis.

32
Symbiosis

• "Symbiosis" means living together. The term does
  not indicate the nature of the relationship.
• Life scientists prefer to use one of the other
  terms that give a more precise indication of the
  relationship.

33
Commensalism

• Commensalism is where one organism benefits but
  does not cause any harm to the other. An example
  is Spanish Moss. It hangs from trees in Florida.
  It is not a parasite all it needs is a place to
  hang. It gets its water from the air.

34
Mutualism

• In mutualism, a mutually beneficial relationship
  exists where both partners benefit. An example
  is the relationship between the legumes (beans,
  peas, clover, alfalfa) and the nitrogen-fixing
  bacteria. The bacteria produce usable nitrogen
  for the plant and the plant gives them a place to
  live.

35
Mutualism

• Termites eat wood which they cannot digest.
  There are bacteria and protozoa in their
  digestive systems that can digest cellulose to
  produce glucose. The microorganisms benefit
  because they have a place to live and a constant
  supply of cellulose to digest. The termites get
  the benefit from the glucose released from the
  cellulose by the bacteria and protozoa.

36
Mutualism

• A cow eats grass that it cannot digest. In the
  multichambered stomach of the cow are bacteria
  and protozoa that digest the cellulose for the
  cow. In return they get a place to live and a
  food supply.

37
Parasitism

• In parasitism, the parasite benefits but the host
  does not. Parasites are generally internal. In
  the lower phyla of the animal kingdom, most
  groups contain one or more parasites of various
  kinds. Parasites require the host for
  reproduction.

38
Predation

• A predator is free-living and feeds on other
  organisms. Some, like lions, kill and eat an
  entire organism. Others, like mosquitoes, take
  only a small part.

39
The End

• Principles of Biology
• Ecology