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.

How Do Organisms Move?

• External environments are challenging.

• Four options for dealing with challenges:– Isolate themselves

– Seek shelter

– Adjust to changing conditions

– Move to more favorable environments

Microbe Movement

• Thick cell walls and shells protect many microbes from potentially hostile environments.

• Microbes can move using flagella, cilia, and pseudopodia (false feet)

Animal Movement

• Involves the interactions between muscles and their shells or skeletons

• Among animals, there exist 3 types of skeletons:– Hydrostatic– Exoskeleton– Endoskeletons

How Do Organism Reproduce?

• 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

• Follows three general types:– Alternating cycle:

• 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

• Simultaneous release of gametes is important. Two reasons:– Facilitates fertilization.

– Foils predators by “flooding the market”.

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.