Circulatory Systems Move
Nutrients, Gases and Other Materials
• Two basic types:
– Open system:
• Blood periodically leaves the blood vessels, bathes the tissues, and is recollected into the vessels.
• Found in arthropods
– Closed system:
• Blood never leaves the blood vessels
• Found in humans and other animals

Circulatory Systems Move
Nutrients, Gases and Other Materials
• Circulatory systems have three main components:
– Vessels
– Blood
– Hearts
– Each evolved from rather simple components in primitive worms to highly complex ones found in chordates.

Animals Must Maintain Proper
Water Balance
• For all cells, water is a precious necessity.
• It is necessary to maintain the appropriate concentrations of solutes in an organism’s body
– Solute concentrations can be different from those found in body compared to the environment.
– Need to have an ability to regulate the solute concentrations due to these differences.

Animals Must Maintain Proper
Water Balance
• Fish living in hypertonic environment:
– Drinks water.
– Loses water through the gills.
– Loses solutes in urine and active transport through the gills.

Animals Must Maintain Proper
Water Balance
• Fish living in hypotonic environment:
– Drinks no water.
– Water absorbed by osmosis through gills and body surfaces.
– Solutes absorbed by active transport at gills.

Animals Must Maintain Proper
Water Balance
• Terrestrial animals have 5 ways to reduce water loss:
– Live in moist environment
– Live in habitat with high humidity
– Be active at night when humidity is the highest
– Special body coverings to prevent water loss.

Animals Must Maintain Proper
Water Balance
• Terrestrial animals have 5 ways to reduce water loss:
– Organisms living in the desert have special mechanisms for reducing water loss in feces and concentrating wastes in urine

Organisms Must Get Rid of
Metabolic Wastes
• Cellular metabolism produces waste compounds that must be disposed of.
– Example: Ammonia
• Animals evolved a number of different excretory systems
– Blind tubes that collect waste to more complex organs such as kidneys.

• External environments are challenging.
• Four options for dealing with challenges:
– Isolate themselves
– Seek shelter
– Adjust to changing conditions
– Move to more favorable environments

• Thick cell walls and shells protect many microbes from potentially hostile environments.
• Microbes can move using flagella, cilia, and pseudopodia (false feet)

• Involves the interactions between muscles and their shells or skeletons
• Among animals, there exist 3 types of skeletons:
– Hydrostatic
– Exoskeleton
– Endoskeletons

• Purpose of life is to reproduce
– Because life can only persist through reproduction
• Two types
– Asexual
• Binary fission or mitosis
– Sexual

Most Common Form of
Reproduction is Asexual
• Process of one cell becoming two
– Binary fission occurs in prokaryotic cells
– Mitosis occurs in all others
• Also allows for tissue repair

Asexual Reproduction

Sexual Reproduction Evolved
Among Bacteria, Protists and Fungi
• Conjugation
– Cytoplasmic bridge
( pilus ) develops between two individuals allowing one-way exchange of genetic material.

Sexual Reproduction Among
Eukaryotes
• Follows three general types
:
– Diploid cycle
:
• Seen in all animals and some protists.
• All cells of the organism are diploid except for gametes.
• Gametes remain single-celled, haploid entities until fertilization.

Sexual Reproduction Among
Eukaryotes
• Follows three general types
:
– Haploid cycle
:
• Seen in all fungi and some algae.
• All cells of the organism are haploid.
• Budding and other types of asexual reproduction produce haploid individuals.
• When reproduce sexually, cells merge, fuse nuclei, and become diploid.
– Immediately undergo meiosis producing haploid spores

Sexual Reproduction Among
Eukaryotes
:
• Seen in all plants and some algae
• Has two distinct generations
– Haploid gametophyte that produces gametes.
– Diploid sporophyte that produce spores.

Sexual Reproduction in Water is
Relatively Easy
• Aquatic organisms spew gametes into the environment
• Gametes must find each other so fertilization can occur
• Timing of gamete release is important

Sexual Reproduction in Water is
Relatively Easy

Sexual Reproduction in Water is
Relatively Easy
• Less danger of gametes drying out.
• Less protected.
• Eggs have less yolk than those that reproduce on land.

Many Animals Successfully
Reproduce on Land
• The ability to reproduce on land apparently evolved independently among segmented worms, mollusks, arthropods and chordates.
• Each group originated in the ocean and evolved successfully in different environments until they became terrestrial organisms.

Many Animals Successfully Reproduce on Land
• Transition from water to land is seen most dramatically by comparing their eggs.
• Marine fish have little yolk and no shells.
• Eggs of freshwater fish amphibians, which reproduce in nutrient-poor environments, have considerable more yolk and are surrounded by slime layers.

Many Animals Successfully
Reproduce on Land
• Eggs of reptiles, birds, and primitive mammals are the largest known, contain relatively huge amounts of yolks.

Many Animals Successfully
Reproduce on Land
• The eggs of advanced mammals have no shells and no yolk.
• Offspring are retained within the female’s body (marsupials) where they are protected and nourished.

After Fertilization, Organisms
Develop and Grow
• Pattern of embryonic development has three general phases.
• First phase: fertilized egg undergoes mitosis which increases the number of cells little or no overall growth in size.

After Fertilization, Organisms
Develop and Grow
• Second phase:
– Involves the early appearance of organ system.
• Third phase:
– Further refinement of organ systems and significant growth.

Animal Development

Two patterns of post-hatching and development in birds
• 1. Hatchlings are virtually helpless and totally dependent on parents for food and protection.
• 2. Hatchlings can find their own food and partially protected from the environment by downy feathers.

Mammals Development
• Mammals are helpless at birth and totally dependent on adults for nourishment and protection
– Initial nourishment provided by mammary glands.
– Following weaning, young are still dependent on adults for food.
– Need to learn where to seek food and shelter, how to avoid predators from associations from parents and adults.