Evolution Flashcards
Define evolution
the cumulative change in the heritable characteristics of a population
Law of fossil succession
the chronological sequence of complexity by which characteristics appear to develop
Define Transitional fossils
Demonstrate that the intermediary forms, that occurred over the evolutionary pathway taken by a single genus.
Define Australopithecus
An early hominin ancestor that first appeared in the fossil records around 4 million years ago.
Define selective breeding
A form of artificial selection, whereby man intervened in breeding of species to produce favourable traits in offspring.
Define comparative anatomy
Shows certain structural features that are similar, implying common ancestry.
Define homologous structures
Anatomical features that are similar in basic structure despite being used in different ways
Define speciation
The evolutionary process by which 2 related populations diverge into separated species.
Define vestigial structures
The presence of functionless and reduced remnants of organs that were once present in their ancestors.
Define biogeography
Describes the distribution of life forms over geographical areas both in the past and the present.
Define adaptation
Are characteristics that make an individual suited to its environment and way of life
Define taxon
Categories that scientists have generated named for. Ways to classify organism
Define cladistics
A system of classification that groups organisms together according to the characteristics that have evolved from.
Define primitive trait
Characteristics that have the same structure and function and evolved early on in the history of the organisms being studied
Define derived trait
Characteristics that have the same structure and function but ahve evolved more recently.
Define clade
A group composed of the most recent common ancestors of the group and all of its descendants).
Define phylogeny
the study of the evolutionary pathways of a species
Annelida
Invertebrate
- Bilateral symmetry
- Mouth & anus
- no skeleton
Mollusca
Invertebrate
- Bilateral symmetry
- Mouth & anus
- exoskeleton
Arthropoda
Invertebrate
- Bilateral
- Mouth & anus
- Internal skeleton
Fish
Vertebrate
- Scales (bony plates)
- External reproduction
- Gills
- Ectothermic
Amphibian
Vertebrate
- moist skin
- external reproduction
- simple lungs
- ectothermic
Reptile
Vertebrate
- Scales (keratin)
- Internal reproduction (soft eggs)
- Lungs with extensive folding
- Ectothermic
Bird
Vertebrate
- Feathers
- Internal reproduction (hard eggs)
- Lungs with bronchial tubes
- Endothermic
Mammal
Vertebrate
- Hair
- internal reproduction (live births)
- lungs with alveoli
- endothermic
Chlorophyta
Non vascular plants
- short and grow closer to the ground
Bryophyta
Non vascular plants
- no true leaves, roots or stems
- Reproduce using spores
- No pollen, ovules, seeds or fruits.
Filicinophyta
Vascular Plants:
- Roots, leaves and non-woody stems usually present
- Leaves often divided into pairs of smaller leaflets.
Reproduce asexually using spores produced on the underside of leaves.
-No pollen, ovules, seeds or fruits.
Coniferophyta
Vascular Plants:
- Roots, leaves and woody stems present
- Leaves often narrow and needle-like with thick waxy cuticle.
- Reproduce sexually (wind pollinated) using pollen, ovules and seeds produced in cones.
Angiospermophyta
Vascular Plants:
- Roots, leaves and stems (usually woody)
- Reproduce sexually using pollen, ovules and seeds produced in flowers.
- Fruits may also develop to disperse the seeds.
Porifera
Invertebrate
- No symmetry
- No mouth or anus
- No skeleton but some have a calcareous exoskeleton or internal spicules (needles)
- Both surfaces covered in many pores for filter feeding
- Sac-like unsegmented body with highly varied shape.
Cnidaria
- Radial symmetry
- Mouth only
- Soft-bodied (no skeleton) but hard corals secrete calcium carbonate
- Tentacles arranged in ring around mouth with stinging cells
- Polyp or medusa shape in jellyfish
Platyhelmintha
- Bilateral
- Mouth only
- Soft-bodied (no skeleton)
- Flat, thin bodies shaped like ribbon
- No lungs
- No blood or gas exchange system
Chordata
- Bilateral symmetry
- Mouth and anus
- Internal skeleton have vertebrate
- Segmented bodies legs or other appendages with joints
- Notochord, develops into dorsal nerve cord