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2020.03.12

First Animals

 

 

Multicellular eukaryotes

No cell wall

Heterotrophic creatures

Cellular respiration: oxidation of organic substances to release energy

Consumers: herbivores, carnivores, omnivores, saprotrophs

 

Nutrition

Metabolism:

Uptake, transformation, getting rid of substances :inorganic (water, ions), organic (carbohydrates, fats, proteins)

Organ system of nutrition

  • Digestion
  • Glands: digestive juices, enzymes in them
  • Digestion: decomposition of large insoluble organic molecules to small soluble molecules
  • Absorption: substances get to the blood through the gut wall

 

Breathing

Cellular respiration

glucose + oxygen = carbon dioxide + water (+ released energy)

Organ system of breathing: changing of respiratory gases (O2, CO2)

 

Excretion

Getting rid of decomposition products and harmful substances

 

Circulation

Transport of

  • respiratory gases
  • alimentary substances
  • decomposition products
  • hormones

Circulation of lymph

In Vertebrates: blood moved by heart in blood vessels

 

Moving

Active dislocation

Muscles

Exo- or endoskeleton

 

Coordination and sensation

Nervous system: electric impulses

Endocrine system: hormones (produced by endocrine glands), chemical

Sensory organs: detect stimuli

 

Reproduction and development

Asexual (only in primitive types) or sexual

Separate sexes: male or female individuals

Hermaphrodites: male and female reproductive organs in one individual

Embryonic development: before birth or hatching

Postembryonic development: after birth or hatching

Direct development: offspring resembles to the parents (mammals, spiders)

Metamorphosis: offspring (larva) is different than the parents (insects, amphibians)

 

 

 

Sponges

 

No tissues and organs

Intracellular digestion

Breathing with diffusion

Body structure

2 cell layers

Cell types:

  • Covering cells
  • Sclerocytes: produce needles (skeleton)
  • Choanocytes: collar and flagellum (food absorption)
  • Amoeboid cells: transport

Importance: water purification

 

 

Cnidarians

 

Radial or sometimes bilateral symmetry

2 main body forms:

  • Swimming medusa
  • Sessile polyp

Water content: 95-99%

 

Tissued animals

2 cell layers: entoderm, ectoderm

Mesogloea: jelly-like substance between them

Parts:

  • Mouth
  • Gastrovascular cavity
  • Epidermis (ectoderm)
  • Gastrodermis (entoderm)
  • Tentacle
  • Mesogloea

Nematocysts: stinging cells

  • On the tentacles, trap the prey

Digestion is started in the gastrovascular cavity and finished in the cells (partially extracellular digestion)

Nervous system: decentralized nerve nets (no brain)

Reproduction

Sexual:

  • complex life cycle with both polyp and medusa stages

Asexual:

  • Budding

Main species

  • Hydra
  • Portuguese Man of War
  • Moon jellyfish
  • Coral

 

 

Animal tissues

 

Cell differentiation: cells become different (sharing of tasks)

Tissue: cells with the same features, role and origin

Matrix: non-living substance among the cells

 

Epithelial tissues

Classification by structure

Simple epithelial tissues

  • Squamous: (endothel)
  • Cuboidal: (in glands)
  • Columnar: (inner wall of the small intestine)

Stratified: columnar (at the bottom), cuboidal, squamous (on the top) layers

  • Non-keratinised: inner wall of the oral cavity, vagina
  • Keratinized: the most apical layers of cells are dead and lose their nucleus and cytoplasm, instead contain a tough, resistant protein called keratin (reptilian, bird, mammal skin)

Pseudostratified:

  • Ciliated: (trachea, Fallopian tube)

Transitional: (bladder)

 

Classification by role

  • Covering, protection: skin, surfaces of organs
  • Sensation: retina, olfactory epithelium
  • Secretion, excretion: glands
  • Absorption: small intestine

 

Connective tissues

  • Matrix: non living material among the cells
  • Protein fibres

Blood: liquid matrix, roles are transport and protection

Areolar connective tissue (loose connective tissue): soft fibres, fills spaces between organs, skin

Fibrous connective tissue (collagenous and elastic fibers): tendons and ligaments

Adipose tissue: stores fat (energy store, insulator, mechanical protector, stores ADEK vitamins)

 

Supporting tissues

Cartilage

  • Elastic
  • Nose, joints
  • Between the vertebrae
  • Ears, larynx, epiglottis

Bone

  • Organic matrix: protein fibres (elastic)
  • Inorganic matrix: ions, salts (rigid)
  • Together: very strong

 

Muscle tissues

  • Contraction: actin and myosin filaments slide closer to each other (60/1)

Types:

Smooth

  • Elongated cells
  • Medium force
  • Slow contraction
  • Involuntary controlled
  • Slowly fatigues
  • In the gut, uterus, bronchioles

Skeletal (striped)

  • Muscle fibres
  • Strong
  • Rapid contraction
  • Voluntary control
  • Fatigues rapidly
  • Attached to the skeleton

Cardiac

  • Branching fibres
  • Strong
  • Contracts rapidly
  • Involuntary and self-generating control
  • Fatigues very slowly
  • In the heart

Nervous tissue

  • Controls and coordinates the activities of the body
  • Specialised elongated cells transmit electric impulses